Long live QColorSpace and friends

Adds QColorSpace and QColorTransform classes,
and parsing of a common subset of ICC profiles
found in images, and also parses the ICC profiles
in PNG and JPEGs.

For backwards compatibility no automatic color
handling is done by this patch.

[ChangeLog][QtGui] A QColorSpace class has been added,
and color spaces are now parsed from PNG and JPEG images.
No automatic color space conversion is done however, and
applications must request it.

Change-Id: Ic09935f84640a716467fa3a9ed1e73c02daf3675
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

17 files changed, 3364 insertions, 49 deletions

diff --git a/src/gui/painting/painting.pri b/src/gui/painting/painting.pri
index c3585a4647..0e2dfed9ab 100644
--- a/src/gui/painting/painting.pri
+++ b/src/gui/painting/painting.pri
@@ -8,7 +8,15 @@ HEADERS += \
         painting/qbrush.h \
         painting/qcolor.h \
         painting/qcolor_p.h \
-        painting/qcolorprofile_p.h \
+        painting/qcolormatrix_p.h \
+        painting/qcolorspace.h \
+        painting/qcolorspace_p.h \
+        painting/qcolortransferfunction_p.h \
+        painting/qcolortransfertable_p.h \
+        painting/qcolortransform.h \
+        painting/qcolortransform_p.h \
+        painting/qcolortrc_p.h \
+        painting/qcolortrclut_p.h \
         painting/qcosmeticstroker_p.h \
         painting/qdatabuffer_p.h \
         painting/qdrawhelper_p.h \
@@ -17,6 +25,7 @@ HEADERS += \
         painting/qemulationpaintengine_p.h \
         painting/qfixed_p.h \
         painting/qgrayraster_p.h \
+        painting/qicc_p.h \
         painting/qmatrix.h \
         painting/qmemrotate_p.h \
         painting/qoutlinemapper_p.h \
@@ -64,12 +73,15 @@ SOURCES += \
         painting/qblittable.cpp \
         painting/qbrush.cpp \
         painting/qcolor.cpp \
-        painting/qcolorprofile.cpp \
+        painting/qcolorspace.cpp \
+        painting/qcolortransform.cpp \
+        painting/qcolortrclut.cpp \
         painting/qcompositionfunctions.cpp \
         painting/qcosmeticstroker.cpp \
         painting/qdrawhelper.cpp \
         painting/qemulationpaintengine.cpp \
         painting/qgrayraster.c \
+        painting/qicc.cpp \
         painting/qimagescale.cpp \
         painting/qmatrix.cpp \
         painting/qmemrotate.cpp \
diff --git a/src/gui/painting/qcolormatrix_p.h b/src/gui/painting/qcolormatrix_p.h
new file mode 100644
index 0000000000..3d1dca6222
--- /dev/null
+++ b/src/gui/painting/qcolormatrix_p.h
@@ -0,0 +1,214 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORMATRIX_H
+#define QCOLORMATRIX_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/qtguiglobal.h>
+#include <cmath>
+
+QT_BEGIN_NAMESPACE
+
+// An abstract 3 value color
+class QColorVector
+{
+public:
+    QColorVector() = default;
+    constexpr QColorVector(float x, float y, float z) : x(x), y(y), z(z), _unused(0.0f) { }
+    float x; // X, x or red
+    float y; // Y, y or green
+    float z; // Z, Y or blue
+    float _unused;
+
+    friend inline bool operator==(const QColorVector &v1, const QColorVector &v2);
+    friend inline bool operator!=(const QColorVector &v1, const QColorVector &v2);
+
+    static constexpr QColorVector null() { return QColorVector(0.0f, 0.0f, 0.0f); }
+    // Common whitepoints on normalized XYZ form:
+    static constexpr QColorVector D50() { return QColorVector(0.96421f, 1.0f, 0.82519f); }
+    static constexpr QColorVector D65() { return QColorVector(0.95043f, 1.0f, 1.08890f); }
+};
+
+inline bool operator==(const QColorVector &v1, const QColorVector &v2)
+{
+    return (std::abs(v1.x - v2.x) < (1.0f / 2048.0f))
+        && (std::abs(v1.y - v2.y) < (1.0f / 2048.0f))
+        && (std::abs(v1.z - v2.z) < (1.0f / 2048.0f));
+}
+
+inline bool operator!=(const QColorVector &v1, const QColorVector &v2)
+{
+    return !(v1 == v2);
+}
+
+
+// A matrix mapping 3 value colors.
+// Not using QMatrix because only floats are needed and performance is critical.
+class QColorMatrix
+{
+public:
+    // We are storing the matrix transposed as that is more convenient:
+    QColorVector r;
+    QColorVector g;
+    QColorVector b;
+
+    friend inline bool operator==(const QColorMatrix &m1, const QColorMatrix &m2);
+    friend inline bool operator!=(const QColorMatrix &m1, const QColorMatrix &m2);
+
+    bool isValid() const
+    {
+        // A color matrix must be invertible
+        float det = r.x * (b.z * g.y - g.z * b.y) -
+                    r.y * (b.z * g.x - g.z * b.x) +
+                    r.z * (b.y * g.x - g.y * b.x);
+        return !qFuzzyIsNull(det);
+    }
+
+    QColorMatrix inverted() const
+    {
+        float det = r.x * (b.z * g.y - g.z * b.y) -
+                    r.y * (b.z * g.x - g.z * b.x) +
+                    r.z * (b.y * g.x - g.y * b.x);
+        det = 1.0f / det;
+        QColorMatrix inv;
+        inv.r.x = (g.y * b.z - b.y * g.z) * det;
+        inv.r.y = (b.y * r.z - r.y * b.z) * det;
+        inv.r.z = (r.y * g.z - g.y * r.z) * det;
+        inv.g.x = (b.x * g.z - g.x * b.z) * det;
+        inv.g.y = (r.x * b.z - b.x * r.z) * det;
+        inv.g.z = (g.x * r.z - r.x * g.z) * det;
+        inv.b.x = (g.x * b.y - b.x * g.y) * det;
+        inv.b.y = (b.x * r.y - r.x * b.y) * det;
+        inv.b.z = (r.x * g.y - g.x * r.y) * det;
+        return inv;
+    }
+    QColorMatrix operator*(const QColorMatrix &o) const
+    {
+        QColorMatrix comb;
+        comb.r.x = r.x * o.r.x + g.x * o.r.y + b.x * o.r.z;
+        comb.g.x = r.x * o.g.x + g.x * o.g.y + b.x * o.g.z;
+        comb.b.x = r.x * o.b.x + g.x * o.b.y + b.x * o.b.z;
+
+        comb.r.y = r.y * o.r.x + g.y * o.r.y + b.y * o.r.z;
+        comb.g.y = r.y * o.g.x + g.y * o.g.y + b.y * o.g.z;
+        comb.b.y = r.y * o.b.x + g.y * o.b.y + b.y * o.b.z;
+
+        comb.r.z = r.z * o.r.x + g.z * o.r.y + b.z * o.r.z;
+        comb.g.z = r.z * o.g.x + g.z * o.g.y + b.z * o.g.z;
+        comb.b.z = r.z * o.b.x + g.z * o.b.y + b.z * o.b.z;
+        return comb;
+
+    }
+    QColorVector map(const QColorVector &c) const
+    {
+        return QColorVector { c.x * r.x + c.y * g.x + c.z * b.x,
+                              c.x * r.y + c.y * g.y + c.z * b.y,
+                              c.x * r.z + c.y * g.z + c.z * b.z };
+    }
+    QColorMatrix transposed() const
+    {
+        return QColorMatrix { { r.x, g.x, b.x },
+                              { r.y, g.y, b.y },
+                              { r.z, g.z, b.z } };
+    }
+
+    static QColorMatrix null()
+    {
+        return { QColorVector::null(), QColorVector::null(), QColorVector::null() };
+    }
+    static QColorMatrix identity()
+    {
+        return { { 1.0f, 0.0f, 0.0f }, { 0.0f, 1.0f, 0.0f }, { 0.0f, 0.0f, 1.0f } };
+    }
+    static QColorMatrix toXyzFromSRgb()
+    {
+        return QColorMatrix { { 0.4360217452f, 0.2224751115f, 0.0139281144f },
+                              { 0.3851087987f, 0.7169067264f, 0.0971015394f },
+                              { 0.1430812478f, 0.0606181994f, 0.7141585946f } };
+    }
+    static QColorMatrix toXyzFromAdobeRgb()
+    {
+        return QColorMatrix { { 0.6097189188f, 0.3111021519f, 0.0194766335f },
+                              { 0.2052682191f, 0.6256770492f, 0.0608891509f },
+                              { 0.1492247432f, 0.0632209629f, 0.7448224425f } };
+    }
+    static QColorMatrix toXyzFromDciP3D65()
+    {
+        return QColorMatrix { { 0.5150973201f, 0.2411795557f, -0.0010491034f },
+                              { 0.2919696569f, 0.6922441125f,  0.0418830328f },
+                              { 0.1571449190f, 0.0665764511f,  0.7843542695f } };
+    }
+    static QColorMatrix toXyzFromProPhotoRgb()
+    {
+        return QColorMatrix { { 0.7976672649f, 0.2880374491f, 0.0000000000f },
+                              { 0.1351922452f, 0.7118769884f, 0.0000000000f },
+                              { 0.0313525312f, 0.0000856627f, 0.8251883388f } };
+    }
+    static QColorMatrix toXyzFromBt2020()
+    {
+        return QColorMatrix { { 0.6506130099f, 0.2695676684f, -0.0018652577f },
+                              { 0.1865101457f, 0.6840794086f,  0.0172256753f },
+                              { 0.1270887405f, 0.0463530831f,  0.8098278046f } };
+    }
+};
+
+inline bool operator==(const QColorMatrix &m1, const QColorMatrix &m2)
+{
+    return (m1.r == m2.r) && (m1.g == m2.g) && (m1.b == m2.b);
+}
+
+inline bool operator!=(const QColorMatrix &m1, const QColorMatrix &m2)
+{
+    return !(m1 == m2);
+}
+
+QT_END_NAMESPACE
+
+#endif // QCOLORMATRIX_P_H
diff --git a/src/gui/painting/qcolorspace.cpp b/src/gui/painting/qcolorspace.cpp
new file mode 100644
index 0000000000..24785f7b61
--- /dev/null
+++ b/src/gui/painting/qcolorspace.cpp
@@ -0,0 +1,633 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qcolorspace.h"
+#include "qcolorspace_p.h"
+
+#include "qcolortransform.h"
+#include "qcolormatrix_p.h"
+#include "qcolortransferfunction_p.h"
+#include "qcolortransform_p.h"
+#include "qicc_p.h"
+
+#include <qmath.h>
+#include <qtransform.h>
+
+#include <qdebug.h>
+
+QT_BEGIN_NAMESPACE
+
+QColorSpacePrivate::QColorSpacePrivate()
+        : id(QColorSpace::Unknown)
+        , gamut(QColorSpace::Gamut::Custom)
+        , transferFunction(QColorSpace::TransferFunction::Custom)
+        , gamma(0.0f)
+        , whitePoint(QColorVector::null())
+        , toXyz(QColorMatrix::null())
+{
+}
+
+QColorSpacePrivate::QColorSpacePrivate(QColorSpace::ColorSpaceId colorSpaceId)
+        : id(colorSpaceId)
+{
+    switch (colorSpaceId) {
+    case QColorSpace::Undefined:
+        gamut = QColorSpace::Gamut::Custom;
+        transferFunction = QColorSpace::TransferFunction::Custom;
+        gamma = 0.0f;
+        description = QStringLiteral("Undefined");
+        break;
+    case QColorSpace::SRgb:
+        gamut = QColorSpace::Gamut::SRgb;
+        transferFunction = QColorSpace::TransferFunction::SRgb;
+        gamma = 2.31f; // ?
+        description = QStringLiteral("sRGB");
+        break;
+    case QColorSpace::SRgbLinear:
+        gamut = QColorSpace::Gamut::SRgb;
+        transferFunction = QColorSpace::TransferFunction::Linear;
+        gamma = 1.0f;
+        description = QStringLiteral("Linear sRGB");
+        break;
+    case QColorSpace::AdobeRgb:
+        gamut = QColorSpace::Gamut::AdobeRgb;
+        transferFunction = QColorSpace::TransferFunction::Gamma;
+        gamma = 2.19921875f; // Not quite 2.2, see https://www.adobe.com/digitalimag/pdfs/AdobeRGB1998.pdf
+        description = QStringLiteral("Adobe RGB");
+        break;
+    case QColorSpace::DisplayP3:
+        gamut = QColorSpace::Gamut::DciP3D65;
+        transferFunction = QColorSpace::TransferFunction::SRgb;
+        gamma = 2.31f; // ?
+        description = QStringLiteral("Display P3");
+        break;
+    case QColorSpace::ProPhotoRgb:
+        gamut = QColorSpace::Gamut::ProPhotoRgb;
+        transferFunction = QColorSpace::TransferFunction::ProPhotoRgb;
+        gamma = 1.8f;
+        description = QStringLiteral("ProPhoto RGB");
+        break;
+    case QColorSpace::Bt2020:
+        gamut = QColorSpace::Gamut::Bt2020;
+        transferFunction = QColorSpace::TransferFunction::Bt2020;
+        gamma = 2.1f; // ?
+        description = QStringLiteral("BT.2020");
+        break;
+    case QColorSpace::Unknown:
+        qWarning("Can not create an unknown color space");
+        Q_FALLTHROUGH();
+    default:
+        Q_UNREACHABLE();
+    }
+    initialize();
+}
+
+QColorSpacePrivate::QColorSpacePrivate(QColorSpace::Gamut gamut, QColorSpace::TransferFunction fun, float gamma)
+        : gamut(gamut)
+        , transferFunction(fun)
+        , gamma(gamma)
+{
+    if (!identifyColorSpace())
+        id = QColorSpace::Unknown;
+    initialize();
+}
+
+bool QColorSpacePrivate::identifyColorSpace()
+{
+    switch (gamut) {
+    case QColorSpace::Gamut::SRgb:
+        if (transferFunction == QColorSpace::TransferFunction::SRgb) {
+            id = QColorSpace::SRgb;
+            description = QStringLiteral("sRGB");
+            return true;
+        }
+        if (transferFunction == QColorSpace::TransferFunction::Linear) {
+            id = QColorSpace::SRgbLinear;
+            description = QStringLiteral("Linear sRGB");
+            return true;
+        }
+        break;
+    case QColorSpace::Gamut::AdobeRgb:
+        if (transferFunction == QColorSpace::TransferFunction::Gamma) {
+            if (qAbs(gamma - 2.19921875f) < (1/1024.0f)) {
+                id = QColorSpace::AdobeRgb;
+                description = QStringLiteral("Adobe RGB");
+                return true;
+            }
+        }
+        break;
+    case QColorSpace::Gamut::DciP3D65:
+        if (transferFunction == QColorSpace::TransferFunction::SRgb) {
+            id = QColorSpace::DisplayP3;
+            description = QStringLiteral("Display P3");
+            return true;
+        }
+        break;
+    case QColorSpace::Gamut::ProPhotoRgb:
+        if (transferFunction == QColorSpace::TransferFunction::ProPhotoRgb) {
+            id = QColorSpace::ProPhotoRgb;
+            description = QStringLiteral("ProPhoto RGB");
+            return true;
+        }
+        if (transferFunction == QColorSpace::TransferFunction::Gamma) {
+            // ProPhoto RGB's curve is effectively gamma 1.8 for 8bit precision.
+            if (qAbs(gamma - 1.8f) < (1/1024.0f)) {
+                id = QColorSpace::ProPhotoRgb;
+                description = QStringLiteral("ProPhoto RGB");
+                return true;
+            }
+        }
+        break;
+    case QColorSpace::Gamut::Bt2020:
+        if (transferFunction == QColorSpace::TransferFunction::Bt2020) {
+            id = QColorSpace::Bt2020;
+            description = QStringLiteral("BT.2020");
+            return true;
+        }
+        break;
+    default:
+        break;
+    }
+    return false;
+}
+
+void QColorSpacePrivate::initialize()
+{
+    setToXyzMatrix();
+    setTransferFunction();
+}
+
+void QColorSpacePrivate::setToXyzMatrix()
+{
+    switch (gamut) {
+    case QColorSpace::Gamut::SRgb:
+        toXyz = QColorMatrix::toXyzFromSRgb();
+        whitePoint = QColorVector::D65();
+        return;
+    case QColorSpace::Gamut::AdobeRgb:
+        toXyz = QColorMatrix::toXyzFromAdobeRgb();
+        whitePoint = QColorVector::D65();
+        return;
+    case QColorSpace::Gamut::DciP3D65:
+        toXyz = QColorMatrix::toXyzFromDciP3D65();
+        whitePoint = QColorVector::D65();
+        return;
+    case QColorSpace::Gamut::ProPhotoRgb:
+        toXyz = QColorMatrix::toXyzFromProPhotoRgb();
+        whitePoint = QColorVector::D50();
+        return;
+    case QColorSpace::Gamut::Bt2020:
+        toXyz = QColorMatrix::toXyzFromBt2020();
+        whitePoint = QColorVector::D65();
+        return;
+    case QColorSpace::Gamut::Custom:
+        toXyz = QColorMatrix::null();
+        whitePoint = QColorVector::D50();
+        return;
+    }
+    Q_UNREACHABLE();
+}
+
+void QColorSpacePrivate::setTransferFunction()
+{
+    switch (transferFunction) {
+    case QColorSpace::TransferFunction::Linear:
+        trc[0].m_type = QColorTrc::Type::Function;
+        trc[0].m_fun = QColorTransferFunction();
+        break;
+    case QColorSpace::TransferFunction::Gamma:
+        trc[0].m_type = QColorTrc::Type::Function;
+        trc[0].m_fun = QColorTransferFunction::fromGamma(gamma);
+        break;
+    case QColorSpace::TransferFunction::SRgb:
+        trc[0].m_type = QColorTrc::Type::Function;
+        trc[0].m_fun = QColorTransferFunction::fromSRgb();
+        break;
+    case QColorSpace::TransferFunction::ProPhotoRgb:
+        trc[0].m_type = QColorTrc::Type::Function;
+        trc[0].m_fun = QColorTransferFunction::fromProPhotoRgb();
+        break;
+    case QColorSpace::TransferFunction::Bt2020:
+        trc[0].m_type = QColorTrc::Type::Function;
+        trc[0].m_fun = QColorTransferFunction::fromBt2020();
+        break;
+    case QColorSpace::TransferFunction::Custom:
+        break;
+    default:
+        Q_UNREACHABLE();
+        break;
+    }
+    trc[1] = trc[0];
+    trc[2] = trc[0];
+}
+
+QColorTransform QColorSpacePrivate::transformationToColorSpace(const QColorSpacePrivate *out) const
+{
+    Q_ASSERT(out);
+    QColorTransform combined;
+    combined.d_ptr.reset(new QColorTransformPrivate);
+    combined.d_ptr->colorSpaceIn = this;
+    combined.d_ptr->colorSpaceOut = out;
+    combined.d_ptr->colorMatrix = out->toXyz.inverted() * toXyz;
+    return combined;
+}
+
+/*!
+    \class QColorSpace
+    \brief The QColorSpace class provides a color space abstraction.
+    \since 5.14
+
+    \ingroup painting
+    \ingroup appearance
+    \inmodule QtGui
+
+    Color values can be interpreted in different ways, and based on the interpretation
+    can live in different spaces. We call this \e {color spaces}.
+
+    QColorSpace provides access to creating several predefined color spaces and
+    can generate QColorTransforms for converting colors from one color space to
+    another.
+
+    QColorSpace can also represent color spaces defined by ICC profiles or embedded
+    in images, that do not otherwise fit the predefined color spaces.
+
+    A color space can generally speaking be conceived as a combination of a transfer
+    function and a gamut. The gamut defines which colors the color space can represent.
+    A color space that can represent a wider range of colors is also known as a
+    wide-gamut color space. The gamut is defined by three primary colors that represent
+    exactly how red, green, and blue look in this particular color space, and a white
+    color that represents where and how bright pure white is.
+
+    The transfer function or gamma curve determines how each component in the
+    color space is encoded. These are used because human perception does not operate
+    linearly, and the transfer functions try to ensure that colors will seem evenly
+    spaced to human eyes.
+*/
+
+
+/*!
+    \enum QColorSpace::ColorSpaceId
+
+    Predefined color spaces.
+
+    \value Undefined An empty, invalid or unsupported color space.
+    \value Unknown A valid color space that doesn't match any of the predefined color spaces.
+    \value SRgb The sRGB color space, which Qt operates in by default. It is a close approximation
+    of how most classic monitors operate, and a mode most software and hardware support.
+    \l{http://www.color.org/chardata/rgb/srgb.xalter}{ICC registration of sRGB}.
+    \value SRgbLinear The sRGB color space with linear gamma. Useful for gamma-corrected blending.
+    \value AdobeRgb The Adobe RGB color space is a classic wide-gamut color space, using a gamma of 2.2.
+    \l{http://www.color.org/chardata/rgb/adobergb.xalter}{ICC registration of Adobe RGB (1998)}
+    \value DisplayP3 A color-space using the primaries of DCI-P3, but with the whitepoint and transfer
+    function of sRGB. Common in modern wide-gamut screens.
+    \l{http://www.color.org/chardata/rgb/DCIP3.xalter}{ICC registration of DCI-P3}
+    \value ProPhotoRgb The Pro Photo RGB color space, also known as ROMM RGB is a very wide gamut color space.
+    \l{http://www.color.org/chardata/rgb/rommrgb.xalter}{ICC registration of ROMM RGB}
+    \value Bt2020 BT.2020 also known as Rec.2020 is the color space of HDR TVs.
+    \l{http://www.color.org/chardata/rgb/BT2020.xalter}{ICC registration of BT.2020}
+*/
+
+/*!
+    \enum QColorSpace::Gamut
+
+    Predefined gamuts, or sets of primary colors.
+
+    \value Custom The gamut is undefined or does not match any predefined sets.
+    \value SRgb The sRGB gamut
+    \value AdobeRgb The Adobe RGB gamut
+    \value DciP3D65 The DCI-P3 gamut with the D65 whitepoint
+    \value ProPhotoRgb The ProPhoto RGB gamut with the D50 whitepoint
+    \value Bt2020 The BT.2020 gamut
+*/
+
+/*!
+    \enum QColorSpace::TransferFunction
+
+    Predefined transfer functions or gamma curves.
+
+    \value Custom The custom or null transfer function
+    \value Linear The linear transfer functions
+    \value Gamma A transfer function that is a real gamma curve based on the value of gamma()
+    \value SRgb The sRGB transfer function, composed of linear and gamma parts
+    \value ProPhotoRgb The ProPhoto RGB transfer function, composed of linear and gamma parts
+    \value Bt2020 The BT.2020 transfer function, composed of linear and gamma parts
+*/
+
+/*!
+    Creates a new colorspace object that represents \a colorSpaceId.
+ */
+QColorSpace::QColorSpace(QColorSpace::ColorSpaceId colorSpaceId)
+{
+    static QExplicitlySharedDataPointer<QColorSpacePrivate> predefinedColorspacePrivates[QColorSpace::Bt2020];
+    if (colorSpaceId <= QColorSpace::Unknown) {
+        if (!predefinedColorspacePrivates[0])
+            predefinedColorspacePrivates[0] = new QColorSpacePrivate(QColorSpace::Undefined);
+        d_ptr = predefinedColorspacePrivates[0]; // unknown and undefined both returns the static undefined colorspace.
+    } else {
+        if (!predefinedColorspacePrivates[colorSpaceId - 1])
+            predefinedColorspacePrivates[colorSpaceId - 1] = new QColorSpacePrivate(colorSpaceId);
+        d_ptr = predefinedColorspacePrivates[colorSpaceId - 1];
+    }
+
+    Q_ASSERT(colorSpaceId == QColorSpace::Undefined || isValid());
+}
+
+/*!
+    Creates a custom color space with the gamut \a gamut, using the transfer function \a fun and
+    optionally \a gamma.
+ */
+QColorSpace::QColorSpace(QColorSpace::Gamut gamut, QColorSpace::TransferFunction fun, float gamma)
+        : d_ptr(new QColorSpacePrivate(gamut, fun, gamma))
+{
+}
+
+/*!
+    Creates a custom color space with the gamut \a gamut, using a gamma transfer function of
+    \a gamma.
+ */
+QColorSpace::QColorSpace(QColorSpace::Gamut gamut, float gamma)
+        : d_ptr(new QColorSpacePrivate(gamut, TransferFunction::Gamma, gamma))
+{
+}
+
+QColorSpace::~QColorSpace()
+{
+}
+
+QColorSpace::QColorSpace(QColorSpace &&colorSpace)
+        : d_ptr(std::move(colorSpace.d_ptr))
+{
+}
+
+QColorSpace::QColorSpace(const QColorSpace &colorSpace)
+        : d_ptr(colorSpace.d_ptr)
+{
+}
+
+QColorSpace &QColorSpace::operator=(QColorSpace &&colorSpace)
+{
+    d_ptr = std::move(colorSpace.d_ptr);
+    return *this;
+}
+
+QColorSpace &QColorSpace::operator=(const QColorSpace &colorSpace)
+{
+    d_ptr = colorSpace.d_ptr;
+    return *this;
+}
+
+/*!
+    Returns the id of the predefined color space this object
+    represents or \c Unknown if it doesn't match any of them.
+*/
+QColorSpace::ColorSpaceId QColorSpace::colorSpaceId() const noexcept
+{
+    return d_ptr->id;
+}
+
+/*!
+    Returns the predefined gamut of the color space
+    or \c Gamut::Custom if it doesn't match any of them.
+*/
+QColorSpace::Gamut QColorSpace::gamut() const noexcept
+{
+    return d_ptr->gamut;
+}
+
+/*!
+    Returns the predefined transfer function of the color space
+    or \c TransferFunction::Custom if it doesn't match any of them.
+
+    \sa gamma()
+*/
+QColorSpace::TransferFunction QColorSpace::transferFunction() const noexcept
+{
+    return d_ptr->transferFunction;
+}
+
+/*!
+    Returns the gamma value of color spaces with \c TransferFunction::Gamma,
+    an approximate gamma value for other predefined color spaces, or
+    0.0 if no approximate gamma is known.
+
+    \sa transferFunction()
+*/
+float QColorSpace::gamma() const noexcept
+{
+    return d_ptr->gamma;
+}
+
+/*!
+    Returns an ICC profile representing the color space.
+
+    If the color space was generated from an ICC profile, that profile
+    is returned, otherwise one is generated.
+
+    \note Even invalid color spaces may return the ICC profile if they
+    were generated from one, to allow applications to implement wider
+    support themselves.
+
+    \sa fromIccProfile()
+*/
+QByteArray QColorSpace::iccProfile() const
+{
+    if (!d_ptr->iccProfile.isEmpty())
+        return d_ptr->iccProfile;
+    if (!isValid())
+        return QByteArray();
+    return QIcc::toIccProfile(*this);
+}
+
+/*!
+    Creates a QColorSpace from ICC profile \a iccProfile.
+
+    \note Not all ICC profiles are supported. QColorSpace only supports
+    RGB-XYZ ICC profiles that are three-component matrix-based.
+
+    If the ICC profile is not supported an invalid QColorSpace is returned
+    where you can still read the original ICC profile using iccProfile().
+
+    \sa iccProfile()
+*/
+QColorSpace QColorSpace::fromIccProfile(const QByteArray &iccProfile)
+{
+    QColorSpace colorSpace;
+    if (QIcc::fromIccProfile(iccProfile, &colorSpace))
+        return colorSpace;
+    colorSpace.d_ptr->id = QColorSpace::Undefined;
+    colorSpace.d_ptr->iccProfile = iccProfile;
+    return colorSpace;
+}
+
+/*!
+    Returns \c true if the color space is valid.
+*/
+bool QColorSpace::isValid() const noexcept
+{
+    return d_ptr->id != QColorSpace::Undefined && d_ptr->toXyz.isValid()
+        && d_ptr->trc[0].isValid() && d_ptr->trc[1].isValid() && d_ptr->trc[2].isValid();
+}
+
+/*!
+    \relates QColorSpace
+    Returns \c true if colorspace \a colorSpace1 is equal to colorspace \a colorSpace2;
+    otherwise returns \c false
+*/
+bool operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2)
+{
+    if (colorSpace1.d_ptr == colorSpace2.d_ptr)
+        return true;
+
+    if (colorSpace1.colorSpaceId() == QColorSpace::Undefined && colorSpace2.colorSpaceId() == QColorSpace::Undefined)
+        return colorSpace1.d_ptr->iccProfile == colorSpace2.d_ptr->iccProfile;
+
+    if (colorSpace1.colorSpaceId() != QColorSpace::Unknown && colorSpace2.colorSpaceId() != QColorSpace::Unknown)
+        return colorSpace1.colorSpaceId() == colorSpace2.colorSpaceId();
+
+    if (colorSpace1.gamut() != QColorSpace::Gamut::Custom && colorSpace2.gamut() != QColorSpace::Gamut::Custom) {
+        if (colorSpace1.gamut() != colorSpace2.gamut())
+            return false;
+    } else {
+        if (colorSpace1.d_ptr->toXyz != colorSpace2.d_ptr->toXyz)
+            return false;
+    }
+
+    if (colorSpace1.transferFunction() != QColorSpace::TransferFunction::Custom &&
+            colorSpace2.transferFunction() != QColorSpace::TransferFunction::Custom) {
+        if (colorSpace1.transferFunction() != colorSpace2.transferFunction())
+            return false;
+        if (colorSpace1.transferFunction() == QColorSpace::TransferFunction::Gamma)
+            return colorSpace1.gamma() == colorSpace2.gamma();
+        return true;
+    }
+
+    if (colorSpace1.d_ptr->trc[0] != colorSpace2.d_ptr->trc[0] ||
+        colorSpace1.d_ptr->trc[1] != colorSpace2.d_ptr->trc[1] ||
+        colorSpace1.d_ptr->trc[2] != colorSpace2.d_ptr->trc[2])
+        return false;
+
+    return true;
+}
+
+/*!
+    \fn bool operator!=(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2)
+    \relates QColorSpace
+
+    Returns \c true if colorspace \a colorspace1 is not equal to colorspace \a colorspace2;
+    otherwise returns \c false
+*/
+
+/*!
+    Generates and returns a color space transformation from this color space to
+    \a colorspace.
+*/
+QColorTransform QColorSpace::transformationToColorSpace(const QColorSpace &colorspace) const
+{
+    if (!isValid() || !colorspace.isValid())
+        return QColorTransform();
+
+    return d_ptr->transformationToColorSpace(colorspace.d_ptr.constData());
+}
+
+/*!
+    \internal
+*/
+QColorSpacePrivate *QColorSpace::d_func()
+{
+    d_ptr.detach();
+    return d_ptr.data();
+}
+
+/*!
+    \fn const QColorSpacePrivate* QColorSpacePrivate::d_func() const
+    \internal
+*/
+
+/*****************************************************************************
+  QColorSpace stream functions
+ *****************************************************************************/
+#if !defined(QT_NO_DATASTREAM)
+/*!
+    \fn QDataStream &operator<<(QDataStream &stream, const QColorSpace &colorSpace)
+    \relates QColorSpace
+
+    Writes the given \a colorSpace to the given \a stream as an ICC profile.
+
+    \sa QColorSpace::iccProfile(), {Serializing Qt Data Types}
+*/
+
+QDataStream &operator<<(QDataStream &s, const QColorSpace &image)
+{
+    s << image.iccProfile();
+    return s;
+}
+
+/*!
+    \fn QDataStream &operator>>(QDataStream &stream, QColorSpace &colorSpace)
+    \relates QColorSpace
+
+    Reads a color space from the given \a stream and stores it in the given
+    \a colorSpace.
+
+    \sa QColorSpace::fromIccProfile(), {Serializing Qt Data Types}
+*/
+
+QDataStream &operator>>(QDataStream &s, QColorSpace &colorSpace)
+{
+    QByteArray iccProfile;
+    s >> iccProfile;
+    colorSpace = QColorSpace::fromIccProfile(iccProfile);
+    return s;
+}
+#endif // QT_NO_DATASTREAM
+
+#ifndef QT_NO_DEBUG_STREAM
+QDebug operator<<(QDebug dbg, const QColorSpace &colorSpace)
+{
+    QDebugStateSaver saver(dbg);
+    dbg.nospace();
+    dbg << "QColorSpace(";
+    dbg << colorSpace.colorSpaceId() << ", " << colorSpace.gamut() << ", " << colorSpace.transferFunction();
+    dbg << ", gamma=" << colorSpace.gamma();
+    dbg << ')';
+    return dbg;
+}
+#endif
+
+QT_END_NAMESPACE
diff --git a/src/gui/painting/qcolorspace.h b/src/gui/painting/qcolorspace.h
new file mode 100644
index 0000000000..923546ec6f
--- /dev/null
+++ b/src/gui/painting/qcolorspace.h
@@ -0,0 +1,136 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORSPACE_H
+#define QCOLORSPACE_H
+
+#include <QtGui/qtguiglobal.h>
+#include <QtGui/qcolortransform.h>
+#include <QtCore/qshareddata.h>
+
+QT_BEGIN_NAMESPACE
+
+class QColorSpacePrivate;
+
+class Q_GUI_EXPORT QColorSpace
+{
+    Q_GADGET
+public:
+    enum ColorSpaceId {
+        Undefined = 0,
+        Unknown = 1,
+        SRgb,
+        SRgbLinear,
+        AdobeRgb,
+        DisplayP3,
+        ProPhotoRgb,
+        Bt2020,
+    };
+    Q_ENUM(ColorSpaceId)
+    enum class Gamut {
+        Custom = 0,
+        SRgb,
+        AdobeRgb,
+        DciP3D65,
+        ProPhotoRgb,
+        Bt2020,
+    };
+    Q_ENUM(Gamut)
+    enum class TransferFunction {
+        Custom = 0,
+        Linear,
+        Gamma,
+        SRgb,
+        ProPhotoRgb,
+        Bt2020,
+    };
+    Q_ENUM(TransferFunction)
+
+    QColorSpace(ColorSpaceId colorSpaceId = Undefined);
+    QColorSpace(Gamut gamut, TransferFunction fun, float gamma = 0.0f);
+    QColorSpace(Gamut gamut, float gamma);
+    ~QColorSpace();
+
+    QColorSpace(QColorSpace &&colorSpace);
+    QColorSpace(const QColorSpace &colorSpace);
+    QColorSpace &operator=(QColorSpace &&colorSpace);
+    QColorSpace &operator=(const QColorSpace &colorSpace);
+
+    ColorSpaceId colorSpaceId() const noexcept;
+    Gamut gamut() const noexcept;
+    TransferFunction transferFunction() const noexcept;
+    float gamma() const noexcept;
+
+    bool isValid() const noexcept;
+
+    friend Q_GUI_EXPORT bool operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2);
+    friend inline bool operator!=(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2);
+
+    static QColorSpace fromIccProfile(const QByteArray &iccProfile);
+    QByteArray iccProfile() const;
+
+    QColorTransform transformationToColorSpace(const QColorSpace &colorspace) const;
+
+    QColorSpacePrivate *d_func();
+    inline const QColorSpacePrivate *d_func() const { return d_ptr.constData(); }
+
+private:
+    friend class QColorSpacePrivate;
+    QExplicitlySharedDataPointer<QColorSpacePrivate> d_ptr;
+};
+
+bool Q_GUI_EXPORT operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2);
+inline bool operator!=(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2)
+{
+    return !(colorSpace1 == colorSpace2);
+}
+
+// QColorSpace stream functions
+#if !defined(QT_NO_DATASTREAM)
+Q_GUI_EXPORT QDataStream &operator<<(QDataStream &, const QColorSpace &);
+Q_GUI_EXPORT QDataStream &operator>>(QDataStream &, QColorSpace &);
+#endif
+
+#ifndef QT_NO_DEBUG_STREAM
+Q_GUI_EXPORT QDebug operator<<(QDebug, const QColorSpace &);
+#endif
+
+QT_END_NAMESPACE
+
+#endif // QCOLORSPACE_P_H
diff --git a/src/gui/painting/qcolorspace_p.h b/src/gui/painting/qcolorspace_p.h
new file mode 100644
index 0000000000..91107a9a89
--- /dev/null
+++ b/src/gui/painting/qcolorspace_p.h
@@ -0,0 +1,96 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORSPACE_P_H
+#define QCOLORSPACE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qcolorspace.h"
+#include "qcolormatrix_p.h"
+#include "qcolortrc_p.h"
+#include "qcolortrclut_p.h"
+
+#include <QtCore/qshareddata.h>
+
+QT_BEGIN_NAMESPACE
+
+class QColorSpacePrivate : public QSharedData
+{
+public:
+    QColorSpacePrivate();
+    QColorSpacePrivate(QColorSpace::ColorSpaceId colorSpaceId);
+    QColorSpacePrivate(QColorSpace::Gamut gamut, QColorSpace::TransferFunction fun, float gamma);
+    QColorSpacePrivate(const QColorSpacePrivate &other) = default;
+    QColorSpacePrivate &operator=(const QColorSpacePrivate &other) = default;
+
+    void initialize();
+    void setToXyzMatrix();
+    void setTransferFunction();
+    bool identifyColorSpace();
+    QColorTransform transformationToColorSpace(const QColorSpacePrivate *out) const;
+
+    QColorSpace::ColorSpaceId id;
+    QColorSpace::Gamut gamut;
+    QColorSpace::TransferFunction transferFunction;
+    float gamma;
+    QColorVector whitePoint;
+
+    QColorTrc trc[3];
+    QColorMatrix toXyz;
+
+    QString description;
+    QByteArray iccProfile;
+
+    mutable QSharedPointer<QColorTrcLut> lut[3];
+    mutable QAtomicInt lutsGenerated;
+};
+
+QT_END_NAMESPACE
+
+#endif // QCOLORSPACE_P_H
diff --git a/src/gui/painting/qcolortransferfunction_p.h b/src/gui/painting/qcolortransferfunction_p.h
new file mode 100644
index 0000000000..fd7cfa2b2b
--- /dev/null
+++ b/src/gui/painting/qcolortransferfunction_p.h
@@ -0,0 +1,207 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORTRANSFERFUNCTION_P_H
+#define QCOLORTRANSFERFUNCTION_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/private/qtguiglobal_p.h>
+
+#include <cmath>
+
+QT_BEGIN_NAMESPACE
+
+// Defines a ICC parametric curve type 4
+class Q_GUI_EXPORT QColorTransferFunction
+{
+public:
+    QColorTransferFunction() noexcept
+            : m_a(1.0f), m_b(0.0f), m_c(1.0f), m_d(0.0f), m_e(0.0f), m_f(0.0f), m_g(1.0f), m_flags(0)
+    { }
+    QColorTransferFunction(float a, float b, float c, float d, float e, float f, float g) noexcept
+            : m_a(a), m_b(b), m_c(c), m_d(d), m_e(e), m_f(f), m_g(g), m_flags(0)
+    { }
+
+    bool isGamma() const
+    {
+        updateHints();
+        return m_flags & quint32(Hints::IsGamma);
+    }
+    bool isLinear() const
+    {
+        updateHints();
+        return m_flags & quint32(Hints::IsLinear);
+    }
+    bool isSRgb() const
+    {
+        updateHints();
+        return m_flags & quint32(Hints::IsSRgb);
+    }
+
+    float apply(float x) const
+    {
+        if (x < m_d)
+            return m_c * x + m_f;
+        else
+            return std::pow(m_a * x + m_b, m_g) + m_e;
+    }
+
+    QColorTransferFunction inverted() const
+    {
+        float a, b, c, d, e, f, g;
+
+        d = m_c * m_d + m_f;
+
+        if (!qFuzzyIsNull(m_c)) {
+            c = 1.0f / m_c;
+            f = -m_f / m_c;
+        } else {
+            c = 0.0f;
+            f = 0.0f;
+        }
+
+        if (!qFuzzyIsNull(m_a) && !qFuzzyIsNull(m_g)) {
+            a = std::pow(1.0f / m_a, m_g);
+            b = -a * m_e;
+            e = -m_b / m_a;
+            g = 1.0f / m_g;
+        } else {
+            a = 0.0f;
+            b = 0.0f;
+            e = 1.0f;
+            g = 1.0f;
+        }
+
+        return QColorTransferFunction(a, b, c, d, e, f, g);
+    }
+
+    // A few predefined curves:
+    static QColorTransferFunction fromGamma(float gamma)
+    {
+        return QColorTransferFunction(1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, gamma);
+    }
+    static QColorTransferFunction fromSRgb()
+    {
+        return QColorTransferFunction(1.0f / 1.055f, 0.055f / 1.055f, 1.0f / 12.92f, 0.04045f, 0.0f, 0.0f, 2.4f);
+    }
+    static QColorTransferFunction fromBt2020()
+    {
+        return QColorTransferFunction(1.0f / 1.0993f, 0.0993f / 1.0993f, 1.0f / 4.5f, 0.08145f, 0.0f, 0.0f, 2.2f);
+    }
+    static QColorTransferFunction fromProPhotoRgb()
+    {
+        return QColorTransferFunction(1.0f, 0.0f, 1.0f / 16.0f, 16.0f / 512.0f, 0.0f, 0.0f, 1.8f);
+    }
+    bool matches(const QColorTransferFunction &o) const
+    {
+        return paramCompare(m_a, o.m_a) && paramCompare(m_b, o.m_b)
+            && paramCompare(m_c, o.m_c) && paramCompare(m_d, o.m_d)
+            && paramCompare(m_e, o.m_e) && paramCompare(m_f, o.m_f)
+            && paramCompare(m_g, o.m_g);
+    }
+    friend inline bool operator==(const QColorTransferFunction &f1, const QColorTransferFunction &f2);
+    friend inline bool operator!=(const QColorTransferFunction &f1, const QColorTransferFunction &f2);
+
+    float m_a;
+    float m_b;
+    float m_c;
+    float m_d;
+    float m_e;
+    float m_f;
+    float m_g;
+
+private:
+    static inline bool paramCompare(float p1, float p2)
+    {
+        // Much fuzzier than fuzzy compare.
+        // It tries match parameters that has been passed through a 8.8
+        // fixed point form.
+        return (qAbs(p1 - p2) <= (1.0f / 512.0f));
+    }
+
+    void updateHints() const
+    {
+        if (m_flags & quint32(Hints::Calculated))
+            return;
+        // We do not consider the case with m_d = 1.0f linear or simple,
+        // since it wouldn't be linear for applyExtended().
+        bool simple = paramCompare(m_a, 1.0f) && paramCompare(m_b, 0.0f)
+                                              && paramCompare(m_d, 0.0f)
+                                              && paramCompare(m_e, 0.0f);
+        if (simple) {
+            m_flags |= quint32(Hints::IsGamma);
+            if (qFuzzyCompare(m_g, 1.0f))
+                m_flags |= quint32(Hints::IsLinear);
+        } else {
+            if (*this == fromSRgb())
+                m_flags |= quint32(Hints::IsSRgb);
+        }
+        m_flags |= quint32(Hints::Calculated);
+    }
+    enum class Hints : quint32 {
+        Calculated = 1,
+        IsGamma = 2,
+        IsLinear = 4,
+        IsSRgb = 8
+    };
+    mutable quint32 m_flags;
+};
+
+inline bool operator==(const QColorTransferFunction &f1, const QColorTransferFunction &f2)
+{
+    return f1.matches(f2);
+}
+inline bool operator!=(const QColorTransferFunction &f1, const QColorTransferFunction &f2)
+{
+    return !f1.matches(f2);
+}
+
+QT_END_NAMESPACE
+
+#endif // QCOLORTRANSFERFUNCTION_P_H
diff --git a/src/gui/painting/qcolortransfertable_p.h b/src/gui/painting/qcolortransfertable_p.h
new file mode 100644
index 0000000000..c8b2f7bd92
--- /dev/null
+++ b/src/gui/painting/qcolortransfertable_p.h
@@ -0,0 +1,245 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORTRANSFERTABLE_P_H
+#define QCOLORTRANSFERTABLE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/private/qtguiglobal_p.h>
+#include "qcolortransferfunction_p.h"
+
+#include <QVector>
+#include <cmath>
+
+QT_BEGIN_NAMESPACE
+
+// Defines either an ICC TRC 'curve' or a lut8/lut16 A or B table
+class Q_GUI_EXPORT QColorTransferTable
+{
+public:
+    QColorTransferTable() noexcept
+            : m_tableSize(0)
+    { }
+    QColorTransferTable(uint32_t size, const QVector<uint8_t> &table) noexcept
+            : m_tableSize(size)
+            , m_table8(table)
+    { }
+    QColorTransferTable(uint32_t size, const QVector<uint16_t> &table) noexcept
+            : m_tableSize(size)
+            , m_table16(table)
+    { }
+
+    bool isValid() const
+    {
+        if (m_tableSize < 2)
+            return false;
+
+#if !defined(QT_NO_DEBUG)
+        // The table must describe an injective curve:
+        if (!m_table8.isEmpty()) {
+            uint8_t val = 0;
+            for (uint i = 0; i < m_tableSize; ++i) {
+                Q_ASSERT(m_table8[i] >= val);
+                val = m_table8[i];
+            }
+        }
+        if (!m_table16.isEmpty()) {
+            uint16_t val = 0;
+            for (uint i = 0; i < m_tableSize; ++i) {
+                Q_ASSERT(m_table16[i] >= val);
+                val = m_table16[i];
+            }
+        }
+#endif
+        return !m_table8.isEmpty() || !m_table16.isEmpty();
+    }
+
+    float apply(float x) const
+    {
+        x = std::min(std::max(x, 0.0f), 1.0f);
+        x *= m_tableSize - 1;
+        uint32_t lo = (int)std::floor(x);
+        uint32_t hi = std::min(lo + 1, m_tableSize);
+        float frac = x - lo;
+        if (!m_table16.isEmpty())
+            return (m_table16[lo] * (1.0f - frac) + m_table16[hi] * frac) * (1.0f/65535.0f);
+        if (!m_table8.isEmpty())
+            return (m_table8[lo] * (1.0f - frac) + m_table8[hi] * frac) * (1.0f/255.0f);
+        return x;
+    }
+
+    // Apply inverse, optimized by giving a previous result a value < x.
+    float applyInverse(float x, float resultLargerThan = 0.0f) const
+    {
+        Q_ASSERT(resultLargerThan >= 0.0f && resultLargerThan <= 1.0f);
+        if (x <= 0.0f)
+            return 0.0f;
+        if (x >= 1.0f)
+            return 1.0f;
+        if (!m_table16.isEmpty()) {
+            float v = x * 65535.0f;
+            uint i = std::floor(resultLargerThan * (m_tableSize - 1)) + 1;
+            for ( ; i < m_tableSize; ++i) {
+                if (m_table16[i] > v)
+                    break;
+            }
+            if (i >= m_tableSize - 1)
+                return 1.0f;
+            float y1 = m_table16[i - 1];
+            float y2 = m_table16[i];
+            Q_ASSERT(x >= y1 && x < y2);
+            float fr = (v - y1) / (y2 - y1);
+            return (i + fr) * (1.0f / (m_tableSize - 1));
+
+        }
+        if (!m_table8.isEmpty()) {
+            float v = x * 255.0f;
+            uint i = std::floor(resultLargerThan * (m_tableSize - 1)) + 1;
+            for ( ; i < m_tableSize; ++i) {
+                if (m_table8[i] > v)
+                    break;
+            }
+            if (i >= m_tableSize - 1)
+                return 1.0f;
+            float y1 = m_table8[i - 1];
+            float y2 = m_table8[i];
+            Q_ASSERT(x >= y1 && x < y2);
+            float fr = (v - y1) / (y2 - y1);
+            return (i + fr) * (1.0f / (m_tableSize - 1));
+        }
+        return x;
+    }
+
+    bool asColorTransferFunction(QColorTransferFunction *transferFn)
+    {
+        Q_ASSERT(isValid());
+        Q_ASSERT(transferFn);
+        if (!m_table8.isEmpty() && (m_table8[0] != 0 || m_table8[m_tableSize - 1] != 255))
+            return false;
+        if (!m_table16.isEmpty() && (m_table16[0] != 0 || m_table16[m_tableSize - 1] != 65535))
+            return false;
+        if (m_tableSize == 2) {
+            *transferFn = QColorTransferFunction(); // Linear
+            return true;
+        }
+        // The following heuristics are based on those from Skia:
+        if (m_tableSize == 26 && !m_table16.isEmpty()) {
+            // code.facebook.com/posts/411525055626587/under-the-hood-improving-facebook-photos
+            if (m_table16[6] != 3062)
+                return false;
+            if (m_table16[12] != 12824)
+                return false;
+            if (m_table16[18] != 31237)
+                return false;
+            *transferFn = QColorTransferFunction::fromSRgb();
+            return true;
+        }
+        if (m_tableSize == 1024 && !m_table16.isEmpty()) {
+            // HP and Canon sRGB gamma tables:
+            if (m_table16[257] != 3366)
+                return false;
+            if (m_table16[513] != 14116)
+                return false;
+            if (m_table16[768] != 34318)
+                return false;
+            *transferFn = QColorTransferFunction::fromSRgb();
+            return true;
+        }
+        if (m_tableSize == 4096 && !m_table16.isEmpty()) {
+            // Nikon, Epson, and lcms2 sRGB gamma tables:
+            if (m_table16[515] != 960)
+                return false;
+            if (m_table16[1025] != 3342)
+                return false;
+            if (m_table16[2051] != 14079)
+                return false;
+            *transferFn = QColorTransferFunction::fromSRgb();
+            return true;
+        }
+        return false;
+    }
+    friend inline bool operator!=(const QColorTransferTable &t1, const QColorTransferTable &t2);
+    friend inline bool operator==(const QColorTransferTable &t1, const QColorTransferTable &t2);
+
+    uint32_t m_tableSize;
+    QVector<uint8_t> m_table8;
+    QVector<uint16_t> m_table16;
+};
+
+inline bool operator!=(const QColorTransferTable &t1, const QColorTransferTable &t2)
+{
+    if (t1.m_tableSize != t2.m_tableSize)
+        return true;
+    if (t1.m_table8.isEmpty() != t2.m_table8.isEmpty())
+        return true;
+    if (t1.m_table16.isEmpty() != t2.m_table16.isEmpty())
+        return true;
+    if (!t1.m_table8.isEmpty()) {
+        for (quint32 i = 0; i < t1.m_tableSize; ++i) {
+            if (t1.m_table8[i] != t2.m_table8[i])
+                return true;
+        }
+    }
+    if (!t1.m_table16.isEmpty()) {
+        for (quint32 i = 0; i < t1.m_tableSize; ++i) {
+            if (t1.m_table16[i] != t2.m_table16[i])
+                return true;
+        }
+    }
+    return false;
+}
+
+inline bool operator==(const QColorTransferTable &t1, const QColorTransferTable &t2)
+{
+    return !(t1 != t2);
+}
+
+QT_END_NAMESPACE
+
+#endif // QCOLORTRANSFERTABLE_P_H
diff --git a/src/gui/painting/qcolortransform.cpp b/src/gui/painting/qcolortransform.cpp
new file mode 100644
index 0000000000..b677c4b36b
--- /dev/null
+++ b/src/gui/painting/qcolortransform.cpp
@@ -0,0 +1,679 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include "qcolortransform.h"
+#include "qcolortransform_p.h"
+
+#include "qcolormatrix_p.h"
+#include "qcolorspace_p.h"
+#include "qcolortrc_p.h"
+#include "qcolortrclut_p.h"
+
+#include <QtCore/qatomic.h>
+#include <QtCore/qmath.h>
+#include <QtGui/qcolor.h>
+#include <QtGui/qtransform.h>
+#include <QtCore/private/qsimd_p.h>
+
+#include <qdebug.h>
+
+QT_BEGIN_NAMESPACE
+
+QColorTrcLut *lutFromTrc(const QColorTrc &trc)
+{
+    if (trc.m_type == QColorTrc::Type::Table)
+        return QColorTrcLut::fromTransferTable(trc.m_table);
+    if (trc.m_type == QColorTrc::Type::Function)
+        return QColorTrcLut::fromTransferFunction(trc.m_fun);
+    qWarning() << "TRC uninitialized";
+    return nullptr;
+}
+
+void QColorTransformPrivate::updateLutsIn() const
+{
+    if (colorSpaceIn->lutsGenerated.loadAcquire())
+        return;
+    for (int i = 0; i < 3; ++i) {
+        if (!colorSpaceIn->trc[i].isValid())
+            return;
+    }
+
+    if (colorSpaceIn->trc[0] == colorSpaceIn->trc[1] && colorSpaceIn->trc[0] == colorSpaceIn->trc[2]) {
+        colorSpaceIn->lut[0].reset(lutFromTrc(colorSpaceIn->trc[0]));
+        colorSpaceIn->lut[1] = colorSpaceIn->lut[0];
+        colorSpaceIn->lut[2] = colorSpaceIn->lut[0];
+    } else {
+        for (int i = 0; i < 3; ++i)
+            colorSpaceIn->lut[i].reset(lutFromTrc(colorSpaceIn->trc[i]));
+    }
+
+    colorSpaceIn->lutsGenerated.storeRelease(1);
+}
+
+void QColorTransformPrivate::updateLutsOut() const
+{
+    if (colorSpaceOut->lutsGenerated.loadAcquire())
+        return;
+    for (int i = 0; i < 3; ++i) {
+        if (!colorSpaceOut->trc[i].isValid())
+            return;
+    }
+
+    if (colorSpaceOut->trc[0] == colorSpaceOut->trc[1] && colorSpaceOut->trc[0] == colorSpaceOut->trc[2]) {
+        colorSpaceOut->lut[0].reset(lutFromTrc(colorSpaceOut->trc[0]));
+        colorSpaceOut->lut[1] = colorSpaceOut->lut[0];
+        colorSpaceOut->lut[2] = colorSpaceOut->lut[0];
+    } else {
+        for (int i = 0; i < 3; ++i)
+            colorSpaceOut->lut[i].reset(lutFromTrc(colorSpaceOut->trc[i]));
+    }
+
+    colorSpaceOut->lutsGenerated.storeRelease(1);
+}
+
+/*!
+    \class QColorTransform
+    \brief The QColorTransform class is a transformation between color spaces.
+    \since 5.14
+
+    \ingroup painting
+    \ingroup appearance
+    \inmodule QtGui
+
+    QColorTransform is an instantiation of a transformation between color spaces.
+    It can be applied on color and pixels to convert them from one color space to
+    another.
+
+    Setting up a QColorTransform takes some preprocessing, so keeping around
+    QColorTransforms that you need often is recommended, instead of generating
+    them on the fly.
+*/
+
+
+QColorTransform::~QColorTransform() noexcept
+{
+}
+
+/*!
+    Applies the color transformation on the QRgb value \a argb.
+
+    The input should be opaque or unpremultiplied.
+*/
+QRgb QColorTransform::map(const QRgb &argb) const
+{
+    if (!d_ptr)
+        return argb;
+    Q_D(const QColorTransform);
+    constexpr float f = 1.0f / 255.0f;
+    QColorVector c = { qRed(argb) * f, qGreen(argb) * f, qBlue(argb) * f };
+    c.x = d->colorSpaceIn->trc[0].apply(c.x);
+    c.y = d->colorSpaceIn->trc[1].apply(c.y);
+    c.z = d->colorSpaceIn->trc[2].apply(c.z);
+    c = d->colorMatrix.map(c);
+    c.x = std::max(0.0f, std::min(1.0f, c.x));
+    c.y = std::max(0.0f, std::min(1.0f, c.y));
+    c.z = std::max(0.0f, std::min(1.0f, c.z));
+    if (d->colorSpaceOut->lutsGenerated.loadAcquire()) {
+        c.x = d->colorSpaceOut->lut[0]->fromLinear(c.x);
+        c.y = d->colorSpaceOut->lut[1]->fromLinear(c.y);
+        c.z = d->colorSpaceOut->lut[2]->fromLinear(c.z);
+    } else {
+        c.x = d->colorSpaceOut->trc[0].applyInverse(c.x);
+        c.y = d->colorSpaceOut->trc[1].applyInverse(c.y);
+        c.z = d->colorSpaceOut->trc[2].applyInverse(c.z);
+    }
+
+    return qRgba(c.x * 255 + 0.5f, c.y * 255 + 0.5f, c.z * 255 + 0.5f, qAlpha(argb));
+}
+
+/*!
+    Applies the color transformation on the QRgba64 value \a rgba64.
+
+    The input should be opaque or unpremultiplied.
+*/
+QRgba64 QColorTransform::map(const QRgba64 &rgba64) const
+{
+    if (!d_ptr)
+        return rgba64;
+    Q_D(const QColorTransform);
+    constexpr float f = 1.0f / 65535.0f;
+    QColorVector c = { rgba64.red() * f, rgba64.green() * f, rgba64.blue() * f };
+    c.x = d->colorSpaceIn->trc[0].apply(c.x);
+    c.y = d->colorSpaceIn->trc[1].apply(c.y);
+    c.z = d->colorSpaceIn->trc[2].apply(c.z);
+    c = d->colorMatrix.map(c);
+    c.x = std::max(0.0f, std::min(1.0f, c.x));
+    c.y = std::max(0.0f, std::min(1.0f, c.y));
+    c.z = std::max(0.0f, std::min(1.0f, c.z));
+    if (d->colorSpaceOut->lutsGenerated.loadAcquire()) {
+        c.x = d->colorSpaceOut->lut[0]->fromLinear(c.x);
+        c.y = d->colorSpaceOut->lut[1]->fromLinear(c.y);
+        c.z = d->colorSpaceOut->lut[2]->fromLinear(c.z);
+    } else {
+        c.x = d->colorSpaceOut->trc[0].applyInverse(c.x);
+        c.y = d->colorSpaceOut->trc[1].applyInverse(c.y);
+        c.z = d->colorSpaceOut->trc[2].applyInverse(c.z);
+    }
+
+    return QRgba64::fromRgba64(c.x * 65535, c.y * 65535, c.z * 65535, rgba64.alpha());
+}
+
+/*!
+    Applies the color transformation on the QColor value \a color.
+
+*/
+QColor QColorTransform::map(const QColor &color) const
+{
+    if (!d_ptr)
+        return color;
+    Q_D(const QColorTransform);
+    QColorVector c = { (float)color.redF(), (float)color.greenF(), (float)color.blueF() };
+    c.x = d->colorSpaceIn->trc[0].apply(c.x);
+    c.y = d->colorSpaceIn->trc[1].apply(c.y);
+    c.z = d->colorSpaceIn->trc[2].apply(c.z);
+    c = d->colorMatrix.map(c);
+    if (d_ptr->colorSpaceOut->lutsGenerated.loadAcquire()) {
+        c.x = d->colorSpaceOut->lut[0]->fromLinear(c.x);
+        c.y = d->colorSpaceOut->lut[1]->fromLinear(c.y);
+        c.z = d->colorSpaceOut->lut[2]->fromLinear(c.z);
+    } else {
+        c.x = d->colorSpaceOut->trc[0].applyInverse(c.x);
+        c.y = d->colorSpaceOut->trc[1].applyInverse(c.y);
+        c.z = d->colorSpaceOut->trc[2].applyInverse(c.z);
+    }
+    QColor out;
+    out.setRgbF(c.x, c.y, c.z, color.alphaF());
+    return out;
+}
+
+// Optimized sub-routines for fast block based conversion:
+
+static void applyMatrix(QColorVector *buffer, const qsizetype len, const QColorMatrix &colorMatrix)
+{
+#if defined(__SSE2__)
+    const __m128 minV = _mm_set1_ps(0.0f);
+    const __m128 maxV = _mm_set1_ps(1.0f);
+    const __m128 xMat = _mm_loadu_ps(&colorMatrix.r.x);
+    const __m128 yMat = _mm_loadu_ps(&colorMatrix.g.x);
+    const __m128 zMat = _mm_loadu_ps(&colorMatrix.b.x);
+    for (qsizetype j = 0; j < len; ++j) {
+        __m128 c = _mm_loadu_ps(&buffer[j].x);
+        __m128 cx = _mm_shuffle_ps(c, c, _MM_SHUFFLE(0, 0, 0, 0));
+        __m128 cy = _mm_shuffle_ps(c, c, _MM_SHUFFLE(1, 1, 1, 1));
+        __m128 cz = _mm_shuffle_ps(c, c, _MM_SHUFFLE(2, 2, 2, 2));
+        cx = _mm_mul_ps(cx, xMat);
+        cy = _mm_mul_ps(cy, yMat);
+        cz = _mm_mul_ps(cz, zMat);
+        cx = _mm_add_ps(cx, cy);
+        cx = _mm_add_ps(cx, cz);
+        // Clamp:
+        cx = _mm_min_ps(cx, maxV);
+        cx = _mm_max_ps(cx, minV);
+        _mm_storeu_ps(&buffer[j].x, cx);
+    }
+#else
+    for (int j = 0; j < len; ++j) {
+        const QColorVector cv = colorMatrix.map(buffer[j]);
+        buffer[j].x = std::max(0.0f, std::min(1.0f, cv.x));
+        buffer[j].y = std::max(0.0f, std::min(1.0f, cv.y));
+        buffer[j].z = std::max(0.0f, std::min(1.0f, cv.z));
+    }
+#endif
+}
+
+template<typename T>
+static void loadPremultiplied(QColorVector *buffer, const T *src, const qsizetype len, const QColorTransformPrivate *d_ptr);
+template<typename T>
+static void loadUnpremultiplied(QColorVector *buffer, const T *src, const qsizetype len, const QColorTransformPrivate *d_ptr);
+
+#if defined(__SSE2__)
+// Load to [0-alpha] in 4x32 SIMD
+template<typename T>
+static inline void loadP(const T &p, __m128i &v);
+
+template<>
+inline void loadP<QRgb>(const QRgb &p, __m128i &v)
+{
+    v = _mm_cvtsi32_si128(p);
+#if defined(__SSE4_1__)
+    v = _mm_cvtepu8_epi32(v);
+#else
+    v = _mm_unpacklo_epi8(v, _mm_setzero_si128());
+    v = _mm_unpacklo_epi16(v, _mm_setzero_si128());
+#endif
+}
+
+template<>
+inline void loadP<QRgba64>(const QRgba64 &p, __m128i &v)
+{
+    v = _mm_loadl_epi64((const __m128i *)&p);
+#if defined(__SSE4_1__)
+    v = _mm_cvtepu16_epi32(v);
+#else
+    v = _mm_unpacklo_epi16(v, _mm_setzero_si128());
+#endif
+    // Shuffle to ARGB as the template below expects it
+    v = _mm_shuffle_epi32(v, _MM_SHUFFLE(3, 0, 1, 2));
+}
+
+template<typename T>
+static void loadPremultiplied(QColorVector *buffer, const T *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    const __m128 v4080 = _mm_set1_ps(4080.f);
+    const __m128 iFF00 = _mm_set1_ps(1.0f / (255 * 256));
+    for (qsizetype i = 0; i < len; ++i) {
+        __m128i v;
+        loadP<T>(src[i], v);
+        __m128 vf = _mm_cvtepi32_ps(v);
+        // Approximate 1/a:
+        __m128 va = _mm_shuffle_ps(vf, vf, _MM_SHUFFLE(3, 3, 3, 3));
+        __m128 via = _mm_rcp_ps(va);
+        via = _mm_sub_ps(_mm_add_ps(via, via), _mm_mul_ps(via, _mm_mul_ps(via, va)));
+        // v * (1/a)
+        vf = _mm_mul_ps(vf, via);
+
+        // Handle zero alpha
+        __m128 vAlphaMask = _mm_cmpeq_ps(va, _mm_set1_ps(0.0f));
+        vf = _mm_andnot_ps(vAlphaMask, vf);
+
+        // LUT
+        v = _mm_cvtps_epi32(_mm_mul_ps(vf, v4080));
+        const int ridx = _mm_extract_epi16(v, 4);
+        const int gidx = _mm_extract_epi16(v, 2);
+        const int bidx = _mm_extract_epi16(v, 0);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[0]->m_toLinear[ridx], 0);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[1]->m_toLinear[gidx], 2);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[2]->m_toLinear[bidx], 4);
+        vf = _mm_mul_ps(_mm_cvtepi32_ps(v), iFF00);
+
+        _mm_storeu_ps(&buffer[i].x, vf);
+    }
+}
+
+// Load to [0-4080] in 4x32 SIMD
+template<typename T>
+static inline void loadPU(const T &p, __m128i &v);
+
+template<>
+inline void loadPU<QRgb>(const QRgb &p, __m128i &v)
+{
+    v = _mm_cvtsi32_si128(p);
+#if defined(__SSE4_1__)
+    v = _mm_cvtepu8_epi32(v);
+#else
+    v = _mm_unpacklo_epi8(v, _mm_setzero_si128());
+    v = _mm_unpacklo_epi16(v, _mm_setzero_si128());
+#endif
+    v = _mm_slli_epi32(v, 4);
+}
+
+template<>
+inline void loadPU<QRgba64>(const QRgba64 &p, __m128i &v)
+{
+    v = _mm_loadl_epi64((const __m128i *)&p);
+    v = _mm_sub_epi16(v, _mm_srli_epi16(v, 8));
+#if defined(__SSE4_1__)
+    v = _mm_cvtepu16_epi32(v);
+#else
+    v = _mm_unpacklo_epi16(v, _mm_setzero_si128());
+#endif
+    v = _mm_srli_epi32(v, 4);
+    // Shuffle to ARGB as the template below expects it
+    v = _mm_shuffle_epi32(v, _MM_SHUFFLE(3, 0, 1, 2));
+}
+
+template<typename T>
+void loadUnpremultiplied(QColorVector *buffer, const T *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    const __m128 iFF00 = _mm_set1_ps(1.0f / (255 * 256));
+    for (qsizetype i = 0; i < len; ++i) {
+        __m128i v;
+        loadPU<T>(src[i], v);
+        const int ridx = _mm_extract_epi16(v, 4);
+        const int gidx = _mm_extract_epi16(v, 2);
+        const int bidx = _mm_extract_epi16(v, 0);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[0]->m_toLinear[ridx], 0);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[1]->m_toLinear[gidx], 2);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceIn->lut[2]->m_toLinear[bidx], 4);
+        __m128 vf = _mm_mul_ps(_mm_cvtepi32_ps(v), iFF00);
+        _mm_storeu_ps(&buffer[i].x, vf);
+    }
+}
+
+#else
+template<>
+void loadPremultiplied<QRgb>(QColorVector *buffer, const QRgb *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+        const uint p = src[i];
+        const int a = qAlpha(p);
+        if (a) {
+            const float ia = 4080.0f / a;
+            const int ridx = int(qRed(p)   * ia + 0.5f);
+            const int gidx = int(qGreen(p) * ia + 0.5f);
+            const int bidx = int(qBlue(p)  * ia + 0.5f);
+            buffer[i].x = d_ptr->colorSpaceIn->lut[0]->m_toLinear[ridx] * (1.0f / (255 * 256));
+            buffer[i].y = d_ptr->colorSpaceIn->lut[1]->m_toLinear[gidx] * (1.0f / (255 * 256));
+            buffer[i].z = d_ptr->colorSpaceIn->lut[2]->m_toLinear[bidx] * (1.0f / (255 * 256));
+        } else {
+            buffer[i].x = buffer[i].y = buffer[i].z = 0.0f;
+        }
+    }
+}
+
+template<>
+void loadPremultiplied<QRgba64>(QColorVector *buffer, const QRgba64 *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+        const QRgba64 &p = src[i];
+        const int a = p.alpha();
+        if (a) {
+            const float ia = 4080.0f / a;
+            const int ridx = int(p.red()   * ia + 0.5f);
+            const int gidx = int(p.green() * ia + 0.5f);
+            const int bidx = int(p.blue()  * ia + 0.5f);
+            buffer[i].x = d_ptr->colorSpaceIn->lut[0]->m_toLinear[ridx] * (1.0f / (255 * 256));
+            buffer[i].y = d_ptr->colorSpaceIn->lut[1]->m_toLinear[gidx] * (1.0f / (255 * 256));
+            buffer[i].z = d_ptr->colorSpaceIn->lut[2]->m_toLinear[bidx] * (1.0f / (255 * 256));
+        } else {
+            buffer[i].x = buffer[i].y = buffer[i].z = 0.0f;
+        }
+    }
+}
+
+template<>
+void loadUnpremultiplied<QRgb>(QColorVector *buffer, const QRgb *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+        const uint p = src[i];
+        buffer[i].x = d_ptr->colorSpaceIn->lut[0]->u8ToLinearF32(qRed(p));
+        buffer[i].y = d_ptr->colorSpaceIn->lut[1]->u8ToLinearF32(qGreen(p));
+        buffer[i].z = d_ptr->colorSpaceIn->lut[2]->u8ToLinearF32(qBlue(p));
+    }
+}
+
+template<>
+void loadUnpremultiplied<QRgba64>(QColorVector *buffer, const QRgba64 *src, const qsizetype len, const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+        const QRgba64 &p = src[i];
+        buffer[i].x = d_ptr->colorSpaceIn->lut[0]->u16ToLinearF32(p.red());
+        buffer[i].y = d_ptr->colorSpaceIn->lut[1]->u16ToLinearF32(p.green());
+        buffer[i].z = d_ptr->colorSpaceIn->lut[2]->u16ToLinearF32(p.blue());
+    }
+}
+#endif
+
+static void storePremultiplied(QRgb *dst, const QRgb *src, const QColorVector *buffer, const qsizetype len,
+                               const QColorTransformPrivate *d_ptr)
+{
+#if defined(__SSE2__)
+    const __m128 v4080 = _mm_set1_ps(4080.f);
+    const __m128 iFF00 = _mm_set1_ps(1.0f / (255 * 256));
+    for (qsizetype i = 0; i < len; ++i) {
+        const int a = qAlpha(src[i]);
+        __m128 vf = _mm_loadu_ps(&buffer[i].x);
+        __m128i v = _mm_cvtps_epi32(_mm_mul_ps(vf, v4080));
+        __m128 va = _mm_set1_ps(a);
+        va = _mm_mul_ps(va, iFF00);
+        const int ridx = _mm_extract_epi16(v, 0);
+        const int gidx = _mm_extract_epi16(v, 2);
+        const int bidx = _mm_extract_epi16(v, 4);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[0]->m_fromLinear[ridx], 4);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[1]->m_fromLinear[gidx], 2);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[2]->m_fromLinear[bidx], 0);
+        vf = _mm_cvtepi32_ps(v);
+        vf = _mm_mul_ps(vf, va);
+        v = _mm_cvtps_epi32(vf);
+        v = _mm_packs_epi32(v, v);
+        v = _mm_insert_epi16(v, a, 3);
+        v = _mm_packus_epi16(v, v);
+        dst[i] = _mm_cvtsi128_si32(v);
+    }
+#else
+    for (qsizetype i = 0; i < len; ++i) {
+        const int a = qAlpha(src[i]);
+        const float fa = a / (255.0f * 256.0f);
+        const float r = d_ptr->colorSpaceOut->lut[0]->m_fromLinear[int(buffer[i].x * 4080.0f + 0.5f)];
+        const float g = d_ptr->colorSpaceOut->lut[1]->m_fromLinear[int(buffer[i].y * 4080.0f + 0.5f)];
+        const float b = d_ptr->colorSpaceOut->lut[2]->m_fromLinear[int(buffer[i].z * 4080.0f + 0.5f)];
+        dst[i] = qRgba(r * fa + 0.5f, g * fa + 0.5f, b * fa + 0.5f, a);
+    }
+#endif
+}
+
+static void storeUnpremultiplied(QRgb *dst, const QRgb *src, const QColorVector *buffer, const qsizetype len,
+                                 const QColorTransformPrivate *d_ptr)
+{
+#if defined(__SSE2__)
+    const __m128 v4080 = _mm_set1_ps(4080.f);
+    for (qsizetype i = 0; i < len; ++i) {
+        const int a = qAlpha(src[i]);
+        __m128 vf = _mm_loadu_ps(&buffer[i].x);
+        __m128i v = _mm_cvtps_epi32(_mm_mul_ps(vf, v4080));
+        const int ridx = _mm_extract_epi16(v, 0);
+        const int gidx = _mm_extract_epi16(v, 2);
+        const int bidx = _mm_extract_epi16(v, 4);
+        v = _mm_setzero_si128();
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[0]->m_fromLinear[ridx], 2);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[1]->m_fromLinear[gidx], 1);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[2]->m_fromLinear[bidx], 0);
+        v = _mm_add_epi16(v, _mm_set1_epi16(0x80));
+        v = _mm_srli_epi16(v, 8);
+        v = _mm_insert_epi16(v, a, 3);
+        v = _mm_packus_epi16(v, v);
+        dst[i] = _mm_cvtsi128_si32(v);
+    }
+#else
+    for (qsizetype i = 0; i < len; ++i) {
+        const int r = d_ptr->colorSpaceOut->lut[0]->u8FromLinearF32(buffer[i].x);
+        const int g = d_ptr->colorSpaceOut->lut[1]->u8FromLinearF32(buffer[i].y);
+        const int b = d_ptr->colorSpaceOut->lut[2]->u8FromLinearF32(buffer[i].z);
+        dst[i] = (src[i] & 0xff000000) | (r << 16) | (g << 8) | (b << 0);
+    }
+#endif
+}
+
+static void storeOpaque(QRgb *dst, const QRgb *src, const QColorVector *buffer, const qsizetype len,
+                        const QColorTransformPrivate *d_ptr)
+{
+    Q_UNUSED(src);
+#if defined(__SSE2__)
+    const __m128 v4080 = _mm_set1_ps(4080.f);
+    for (qsizetype i = 0; i < len; ++i) {
+        __m128 vf = _mm_loadu_ps(&buffer[i].x);
+        __m128i v = _mm_cvtps_epi32(_mm_mul_ps(vf, v4080));
+        const int ridx = _mm_extract_epi16(v, 0);
+        const int gidx = _mm_extract_epi16(v, 2);
+        const int bidx = _mm_extract_epi16(v, 4);
+        v = _mm_setzero_si128();
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[0]->m_fromLinear[ridx], 2);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[1]->m_fromLinear[gidx], 1);
+        v = _mm_insert_epi16(v, d_ptr->colorSpaceOut->lut[2]->m_fromLinear[bidx], 0);
+        v = _mm_add_epi16(v, _mm_set1_epi16(0x80));
+        v = _mm_srli_epi16(v, 8);
+        v = _mm_insert_epi16(v, 255, 3);
+        v = _mm_packus_epi16(v, v);
+        dst[i] = _mm_cvtsi128_si32(v);
+    }
+#else
+    for (qsizetype i = 0; i < len; ++i) {
+        const int r = d_ptr->colorSpaceOut->lut[0]->u8FromLinearF32(buffer[i].x);
+        const int g = d_ptr->colorSpaceOut->lut[1]->u8FromLinearF32(buffer[i].y);
+        const int b = d_ptr->colorSpaceOut->lut[2]->u8FromLinearF32(buffer[i].z);
+        dst[i] = 0xff000000 | (r << 16) | (g << 8) | (b << 0);
+    }
+#endif
+}
+
+static void storePremultiplied(QRgba64 *dst, const QRgba64 *src, const QColorVector *buffer, const qsizetype len,
+                               const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+        const int a = src[i].alpha();
+        const float fa = a / (255.0f * 256.0f);
+        const float r = d_ptr->colorSpaceOut->lut[0]->m_fromLinear[int(buffer[i].x * 4080.0f + 0.5f)];
+        const float g = d_ptr->colorSpaceOut->lut[1]->m_fromLinear[int(buffer[i].y * 4080.0f + 0.5f)];
+        const float b = d_ptr->colorSpaceOut->lut[2]->m_fromLinear[int(buffer[i].z * 4080.0f + 0.5f)];
+        dst[i] = qRgba64(r * fa + 0.5f, g * fa + 0.5f, b * fa + 0.5f, a);
+    }
+}
+
+static void storeUnpremultiplied(QRgba64 *dst, const QRgba64 *src, const QColorVector *buffer, const qsizetype len,
+                                 const QColorTransformPrivate *d_ptr)
+{
+    for (qsizetype i = 0; i < len; ++i) {
+         const int r = d_ptr->colorSpaceOut->lut[0]->u16FromLinearF32(buffer[i].x);
+         const int g = d_ptr->colorSpaceOut->lut[1]->u16FromLinearF32(buffer[i].y);
+         const int b = d_ptr->colorSpaceOut->lut[2]->u16FromLinearF32(buffer[i].z);
+         dst[i] = qRgba64(r, g, b, src[i].alpha());
+    }
+}
+
+static void storeOpaque(QRgba64 *dst, const QRgba64 *src, const QColorVector *buffer, const qsizetype len,
+                        const QColorTransformPrivate *d_ptr)
+{
+    Q_UNUSED(src);
+    for (qsizetype i = 0; i < len; ++i) {
+        const int r = d_ptr->colorSpaceOut->lut[0]->u16FromLinearF32(buffer[i].x);
+        const int g = d_ptr->colorSpaceOut->lut[1]->u16FromLinearF32(buffer[i].y);
+        const int b = d_ptr->colorSpaceOut->lut[2]->u16FromLinearF32(buffer[i].z);
+        dst[i] = qRgba64(r, g, b, 0xFFFF);
+    }
+}
+
+static constexpr qsizetype WorkBlockSize = 256;
+
+template<typename T>
+void QColorTransformPrivate::apply(T *dst, const T *src, qsizetype count, TransformFlags flags) const
+{
+    if (!colorMatrix.isValid())
+        return;
+
+    updateLutsIn();
+    updateLutsOut();
+
+    bool doApplyMatrix = (colorMatrix != QColorMatrix::identity());
+
+    QColorVector buffer[WorkBlockSize];
+    qsizetype i = 0;
+    while (i < count) {
+        const qsizetype len = qMin(count - i, WorkBlockSize);
+        if (flags & InputPremultiplied)
+            loadPremultiplied(buffer, src + i, len, this);
+        else
+            loadUnpremultiplied(buffer, src + i, len, this);
+
+        if (doApplyMatrix)
+            applyMatrix(buffer, len, colorMatrix);
+
+        if (flags & InputOpaque)
+            storeOpaque(dst + i, src + i, buffer, len, this);
+        else if (flags & OutputPremultiplied)
+            storePremultiplied(dst + i, src + i, buffer, len, this);
+        else
+            storeUnpremultiplied(dst + i, src + i, buffer, len, this);
+
+        i += len;
+    }
+}
+
+/*!
+    \internal
+    \enum QColorTransformPrivate::TransformFlag
+
+    Defines how the transform is to be applied.
+
+    \value Unpremultiplied The input and output should both be unpremultiplied.
+    \value InputOpaque The input is guaranteed to be opaque.
+    \value InputPremultiplied The input is premultiplied.
+    \value OutputPremultiplied The output should be premultiplied.
+    \value Premultiplied Both input and output should both be premultiplied.
+*/
+
+/*!
+    \internal
+    Prepares a color transformation for fast application. You do not need to
+    call this explicitly as it will be called implicitly on the first transforms, but
+    if you want predictable performance on the first transforms, you can perform it
+    in advance.
+
+    \sa QColorTransform::map(), apply()
+*/
+void QColorTransformPrivate::prepare()
+{
+    updateLutsIn();
+    updateLutsOut();
+}
+
+/*!
+    \internal
+    Applies the color transformation on \a count QRgb pixels starting from
+    \a src and stores the result in \a dst.
+
+    Thread-safe if prepare() has been called first.
+
+    Assumes unpremultiplied data by default. Set \a flags to change defaults.
+
+    \sa prepare()
+*/
+void QColorTransformPrivate::apply(QRgb *dst, const QRgb *src, qsizetype count, TransformFlags flags) const
+{
+    apply<QRgb>(dst, src, count, flags);
+}
+
+/*!
+    \internal
+    Applies the color transformation on \a count QRgba64 pixels starting from
+    \a src and stores the result in \a dst.
+
+    Thread-safe if prepare() has been called first.
+
+    Assumes unpremultiplied data by default. Set \a flags to change defaults.
+
+    \sa prepare()
+*/
+void QColorTransformPrivate::apply(QRgba64 *dst, const QRgba64 *src, qsizetype count, TransformFlags flags) const
+{
+    apply<QRgba64>(dst, src, count, flags);
+}
+
+
+QT_END_NAMESPACE
diff --git a/src/gui/painting/qcolortransform.h b/src/gui/painting/qcolortransform.h
new file mode 100644
index 0000000000..9274387b97
--- /dev/null
+++ b/src/gui/painting/qcolortransform.h
@@ -0,0 +1,93 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORTRANSFORM_H
+#define QCOLORTRANSFORM_H
+
+#include <QtGui/qtguiglobal.h>
+#include <QtCore/qsharedpointer.h>
+#include <QtGui/qrgb.h>
+
+QT_BEGIN_NAMESPACE
+
+class QColor;
+class QRgba64;
+class QColorSpacePrivate;
+class QColorTransformPrivate;
+
+class Q_GUI_EXPORT QColorTransform
+{
+public:
+    QColorTransform() noexcept : d_ptr(nullptr) { }
+    ~QColorTransform() noexcept;
+    QColorTransform(const QColorTransform &colorTransform) noexcept
+            : d_ptr(colorTransform.d_ptr)
+    { }
+    QColorTransform(QColorTransform &&colorTransform) noexcept
+            : d_ptr(std::move(colorTransform.d_ptr))
+    { }
+    QColorTransform &operator=(const QColorTransform &other) noexcept
+    {
+        d_ptr = other.d_ptr;
+        return *this;
+    }
+    QColorTransform &operator=(QColorTransform &&other) noexcept
+    {
+        d_ptr = std::move(other.d_ptr);
+        return *this;
+    }
+
+    bool isNull() const { return d_ptr.isNull(); }
+
+    QRgb map(const QRgb &argb) const;
+    QRgba64 map(const QRgba64 &rgba64) const;
+    QColor map(const QColor &color) const;
+
+private:
+    friend class QColorSpace;
+    friend class QColorSpacePrivate;
+    friend class QImage;
+
+    Q_DECLARE_PRIVATE(QColorTransform)
+    QSharedPointer<QColorTransformPrivate> d_ptr;
+};
+
+QT_END_NAMESPACE
+
+#endif // QCOLORTRANSFORM_H
diff --git a/src/gui/painting/qcolortransform_p.h b/src/gui/painting/qcolortransform_p.h
new file mode 100644
index 0000000000..74a1e7fe0a
--- /dev/null
+++ b/src/gui/painting/qcolortransform_p.h
@@ -0,0 +1,89 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORTRANSFORM_P_H
+#define QCOLORTRANSFORM_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qcolormatrix_p.h"
+#include "qcolorspace_p.h"
+
+QT_BEGIN_NAMESPACE
+
+class QColorTransformPrivate
+{
+public:
+    QColorMatrix colorMatrix;
+    QExplicitlySharedDataPointer<const QColorSpacePrivate> colorSpaceIn;
+    QExplicitlySharedDataPointer<const QColorSpacePrivate> colorSpaceOut;
+
+    void updateLutsIn() const;
+    void updateLutsOut() const;
+    bool simpleGammaCorrection() const;
+
+    void prepare();
+    enum TransformFlag {
+        Unpremultiplied = 0,
+        InputOpaque = 1,
+        InputPremultiplied = 2,
+        OutputPremultiplied = 4,
+        Premultiplied = (InputPremultiplied | OutputPremultiplied)
+    };
+    Q_DECLARE_FLAGS(TransformFlags, TransformFlag)
+
+    void apply(QRgb *dst, const QRgb *src, qsizetype count, TransformFlags flags = Unpremultiplied) const;
+    void apply(QRgba64 *dst, const QRgba64 *src, qsizetype count, TransformFlags flags = Unpremultiplied) const;
+
+    template<typename T>
+    void apply(T *dst, const T *src, qsizetype count, TransformFlags flags) const;
+};
+
+QT_END_NAMESPACE
+
+#endif // QCOLORTRANSFORM_P_H
diff --git a/src/gui/painting/qcolortrc_p.h b/src/gui/painting/qcolortrc_p.h
new file mode 100644
index 0000000000..3a649f3756
--- /dev/null
+++ b/src/gui/painting/qcolortrc_p.h
@@ -0,0 +1,129 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QCOLORTRC_P_H
+#define QCOLORTRC_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/private/qtguiglobal_p.h>
+#include "qcolortransferfunction_p.h"
+#include "qcolortransfertable_p.h"
+
+QT_BEGIN_NAMESPACE
+
+
+// Defines an ICC TRC (Tone Reproduction Curve)
+class Q_GUI_EXPORT QColorTrc
+{
+public:
+    QColorTrc() noexcept : m_type(Type::Uninitialized)
+    { }
+    QColorTrc(const QColorTransferFunction &fun) : m_type(Type::Function), m_fun(fun)
+    { }
+    QColorTrc(const QColorTransferTable &table) : m_type(Type::Table), m_table(table)
+    { }
+
+    enum class Type {
+        Uninitialized,
+        Function,
+        Table
+    };
+
+    bool isLinear() const
+    {
+        return m_type == Type::Uninitialized || (m_type == Type::Function && m_fun.isLinear());
+    }
+    bool isValid() const
+    {
+        return m_type != Type::Uninitialized;
+    }
+    float apply(float x) const
+    {
+        if (m_type == Type::Table)
+            return m_table.apply(x);
+        if (m_type == Type::Function)
+            return m_fun.apply(x);
+        return x;
+    }
+
+    float applyInverse(float x) const
+    {
+        if (m_type == Type::Table)
+            return m_table.applyInverse(x);
+        if (m_type == Type::Function)
+            return m_fun.inverted().apply(x);
+        return x;
+    }
+
+    friend inline bool operator!=(const QColorTrc &o1, const QColorTrc &o2);
+    friend inline bool operator==(const QColorTrc &o1, const QColorTrc &o2);
+
+    Type m_type;
+    QColorTransferFunction m_fun;
+    QColorTransferTable m_table;
+};
+
+inline bool operator!=(const QColorTrc &o1, const QColorTrc &o2)
+{
+    if (o1.m_type != o2.m_type)
+        return true;
+    if (o1.m_type == QColorTrc::Type::Function)
+        return o1.m_fun != o2.m_fun;
+    if (o1.m_type == QColorTrc::Type::Table)
+        return o1.m_table != o2.m_table;
+    return false;
+}
+inline bool operator==(const QColorTrc &o1, const QColorTrc &o2)
+{
+    return !(o1 != o2);
+}
+
+QT_END_NAMESPACE
+
+#endif // QCOLORTRC
diff --git a/src/gui/painting/qcolorprofile.cpp b/src/gui/painting/qcolortrclut.cpp
index 3b7b0a248b..268d7252b4 100644
--- a/src/gui/painting/qcolorprofile.cpp
+++ b/src/gui/painting/qcolortrclut.cpp
@@ -37,14 +37,16 @@
 **
 ****************************************************************************/
 
-#include "qcolorprofile_p.h"
+#include "qcolortrclut_p.h"
+#include "qcolortransferfunction_p.h"
+#include "qcolortransfertable_p.h"
 #include <qmath.h>
 
 QT_BEGIN_NAMESPACE
 
-QColorProfile *QColorProfile::fromGamma(qreal gamma)
+QColorTrcLut *QColorTrcLut::fromGamma(qreal gamma)
 {
-    QColorProfile *cp = new QColorProfile;
+    QColorTrcLut *cp = new QColorTrcLut;
 
     for (int i = 0; i <= (255 * 16); ++i) {
         cp->m_toLinear[i] = ushort(qRound(qPow(i / qreal(255 * 16), gamma) * (255 * 256)));
@@ -54,31 +56,28 @@ QColorProfile *QColorProfile::fromGamma(qreal gamma)
     return cp;
 }
 
-static qreal srgbToLinear(qreal v)
+QColorTrcLut *QColorTrcLut::fromTransferFunction(const QColorTransferFunction &fun)
 {
-    const qreal a = 0.055;
-    if (v <= qreal(0.04045))
-        return v / qreal(12.92);
-    else
-        return qPow((v + a) / (qreal(1) + a), qreal(2.4));
-}
+    QColorTrcLut *cp = new QColorTrcLut;
+    QColorTransferFunction inv = fun.inverted();
 
-static qreal linearToSrgb(qreal v)
-{
-    const qreal a = 0.055;
-    if (v <= qreal(0.0031308))
-        return v * qreal(12.92);
-    else
-        return (qreal(1) + a) * qPow(v, qreal(1.0 / 2.4)) - a;
+    for (int i = 0; i <= (255 * 16); ++i) {
+        cp->m_toLinear[i] = ushort(qRound(fun.apply(i / qreal(255 * 16)) * (255 * 256)));
+        cp->m_fromLinear[i] = ushort(qRound(inv.apply(i / qreal(255 * 16)) * (255 * 256)));
+    }
+
+    return cp;
 }
 
-QColorProfile *QColorProfile::fromSRgb()
+QColorTrcLut *QColorTrcLut::fromTransferTable(const QColorTransferTable &table)
 {
-    QColorProfile *cp = new QColorProfile;
+    QColorTrcLut *cp = new QColorTrcLut;
 
+    float minInverse = 0.0f;
     for (int i = 0; i <= (255 * 16); ++i) {
-        cp->m_toLinear[i] = ushort(qRound(srgbToLinear(i / qreal(255 * 16)) * (255 * 256)));
-        cp->m_fromLinear[i] = ushort(qRound(linearToSrgb(i / qreal(255 * 16)) * (255 * 256)));
+        cp->m_toLinear[i] = ushort(qBound(0, qRound(table.apply(i / qreal(255 * 16)) * (255 * 256)), 65280));
+        minInverse = table.applyInverse(i / qreal(255 * 16), minInverse);
+        cp->m_fromLinear[i] = ushort(qBound(0, qRound(minInverse * (255 * 256)), 65280));
     }
 
     return cp;
diff --git a/src/gui/painting/qcolorprofile_p.h b/src/gui/painting/qcolortrclut_p.h
index 425e9abace..76a6a60803 100644
--- a/src/gui/painting/qcolorprofile_p.h
+++ b/src/gui/painting/qcolortrclut_p.h
@@ -37,8 +37,8 @@
 **
 ****************************************************************************/
 
-#ifndef QCOLORPROFILE_P_H
-#define QCOLORPROFILE_P_H
+#ifndef QCOLORTRCLUT_P_H
+#define QCOLORTRCLUT_P_H
 
 //
 //  W A R N I N G
@@ -52,21 +52,29 @@
 //
 
 #include <QtGui/private/qtguiglobal_p.h>
+#include <QtCore/qsharedpointer.h>
 #include <QtGui/qrgb.h>
 #include <QtGui/qrgba64.h>
 
+#include <cmath>
+
 #if defined(__SSE2__)
 #include <emmintrin.h>
 #elif defined(__ARM_NEON__) || defined(__ARM_NEON)
 #include <arm_neon.h>
 #endif
+
 QT_BEGIN_NAMESPACE
 
-class Q_GUI_EXPORT QColorProfile
+class QColorTransferFunction;
+class QColorTransferTable;
+
+class Q_GUI_EXPORT QColorTrcLut : public QEnableSharedFromThis<QColorTrcLut>
 {
 public:
-    static QColorProfile *fromGamma(qreal gamma);
-    static QColorProfile *fromSRgb();
+    static QColorTrcLut *fromGamma(qreal gamma);
+    static QColorTrcLut *fromTransferFunction(const QColorTransferFunction &transfn);
+    static QColorTrcLut *fromTransferTable(const QColorTransferTable &transTable);
 
     // The following methods all convert opaque or unpremultiplied colors:
 
@@ -121,6 +129,25 @@ public:
         return convertWithTable(rgb64, m_toLinear);
     }
 
+    float u8ToLinearF32(int c) const
+    {
+        ushort v = m_toLinear[c << 4];
+        return v * (1.0f / (255*256));
+    }
+
+    float u16ToLinearF32(int c) const
+    {
+        c -= (c >> 8);
+        ushort v = m_toLinear[c >> 4];
+        return v * (1.0f / (255*256));
+    }
+
+    float toLinear(float f) const
+    {
+        ushort v = m_toLinear[(int)(f * (255 * 16) + 0.5f)];
+        return v * (1.0f / (255*256));
+    }
+
     QRgb fromLinear64(QRgba64 rgb64) const
     {
 #if defined(__SSE2__)
@@ -176,8 +203,31 @@ public:
         return convertWithTable(rgb64, m_fromLinear);
     }
 
+    int u8FromLinearF32(float f) const
+    {
+        ushort v = m_fromLinear[(int)(f * (255 * 16) + 0.5f)];
+        return (v + 0x80) >> 8;
+    }
+    int u16FromLinearF32(float f) const
+    {
+        ushort v = m_fromLinear[(int)(f * (255 * 16) + 0.5f)];
+        return v + (v >> 8);
+    }
+    float fromLinear(float f) const
+    {
+        ushort v = m_fromLinear[(int)(f * (255 * 16) + 0.5f)];
+        return v * (1.0f / (255*256));
+    }
+
+    // We translate to 0-65280 (255*256) instead to 0-65535 to make simple
+    // shifting an accurate conversion.
+    // We translate from 0-4080 (255*16) for the same speed up, and to keep
+    // the tables small enough to fit in most inner caches.
+    ushort m_toLinear[(255 * 16) + 1]; // [0-4080] -> [0-65280]
+    ushort m_fromLinear[(255 * 16) + 1]; // [0-4080] -> [0-65280]
+
 private:
-    QColorProfile() { }
+    QColorTrcLut() { }
 
     Q_ALWAYS_INLINE static QRgb convertWithTable(QRgb rgb32, const ushort *table)
     {
@@ -230,16 +280,8 @@ private:
         return QRgba64::fromRgba64(r, g, b, rgb64.alpha());
 #endif
     }
-
-    // We translate to 0-65280 (255*256) instead to 0-65535 to make simple
-    // shifting an accurate conversion.
-    // We translate from 0-4080 (255*16) for the same speed up, and to keep
-    // the tables small enough to fit in most inner caches.
-    ushort m_toLinear[(255 * 16) + 1]; // [0-4080] -> [0-65280]
-    ushort m_fromLinear[(255 * 16) + 1]; // [0-4080] -> [0-65280]
-
 };
 
 QT_END_NAMESPACE
 
-#endif // QCOLORPROFILE_P_H
+#endif // QCOLORTRCLUT_P_H
diff --git a/src/gui/painting/qdrawhelper.cpp b/src/gui/painting/qdrawhelper.cpp
index 2dd18f6dfc..1ed51d26a2 100644
--- a/src/gui/painting/qdrawhelper.cpp
+++ b/src/gui/painting/qdrawhelper.cpp
@@ -43,7 +43,7 @@
 #include <qstylehints.h>
 #include <qguiapplication.h>
 #include <qatomic.h>
-#include <private/qcolorprofile_p.h>
+#include <private/qcolortrclut_p.h>
 #include <private/qdrawhelper_p.h>
 #include <private/qpaintengine_raster_p.h>
 #include <private/qpainter_p.h>
@@ -5523,7 +5523,7 @@ inline static void qt_bitmapblit_quint16(QRasterBuffer *rasterBuffer,
                                     map, mapWidth, mapHeight, mapStride);
 }
 
-static inline void alphamapblend_generic(int coverage, QRgba64 *dest, int x, const QRgba64 &srcLinear, const QRgba64 &src, const QColorProfile *colorProfile)
+static inline void alphamapblend_generic(int coverage, QRgba64 *dest, int x, const QRgba64 &srcLinear, const QRgba64 &src, const QColorTrcLut *colorProfile)
 {
     if (coverage == 0) {
         // nothing
@@ -5558,7 +5558,7 @@ static void qt_alphamapblit_generic(QRasterBuffer *rasterBuffer,
     if (color.isTransparent())
         return;
 
-    const QColorProfile *colorProfile = nullptr;
+    const QColorTrcLut *colorProfile = nullptr;
 
     if (useGammaCorrection)
         colorProfile = QGuiApplicationPrivate::instance()->colorProfileForA8Text();
@@ -5684,7 +5684,7 @@ void qt_alphamapblit_quint16(QRasterBuffer *rasterBuffer,
     }
 }
 
-static inline void rgbBlendPixel(quint32 *dst, int coverage, QRgba64 slinear, const QColorProfile *colorProfile)
+static inline void rgbBlendPixel(quint32 *dst, int coverage, QRgba64 slinear, const QColorTrcLut *colorProfile)
 {
     // Do a gammacorrected RGB alphablend...
     const QRgba64 dlinear = colorProfile ? colorProfile->toLinear64(*dst) : QRgba64::fromArgb32(*dst);
@@ -5694,7 +5694,7 @@ static inline void rgbBlendPixel(quint32 *dst, int coverage, QRgba64 slinear, co
     *dst = colorProfile ? colorProfile->fromLinear64(blend) : toArgb32(blend);
 }
 
-static inline void grayBlendPixel(quint32 *dst, int coverage, QRgba64 srcLinear, const QColorProfile *colorProfile)
+static inline void grayBlendPixel(quint32 *dst, int coverage, QRgba64 srcLinear, const QColorTrcLut *colorProfile)
 {
     // Do a gammacorrected gray alphablend...
     const QRgba64 dstLinear = colorProfile ? colorProfile->toLinear64(*dst) : QRgba64::fromArgb32(*dst);
@@ -5704,7 +5704,7 @@ static inline void grayBlendPixel(quint32 *dst, int coverage, QRgba64 srcLinear,
     *dst = colorProfile ? colorProfile->fromLinear64(blend) : toArgb32(blend);
 }
 
-static inline void alphamapblend_argb32(quint32 *dst, int coverage, QRgba64 srcLinear, quint32 src, const QColorProfile *colorProfile)
+static inline void alphamapblend_argb32(quint32 *dst, int coverage, QRgba64 srcLinear, quint32 src, const QColorTrcLut *colorProfile)
 {
     if (coverage == 0) {
         // nothing
@@ -5734,7 +5734,7 @@ static void qt_alphamapblit_argb32(QRasterBuffer *rasterBuffer,
     if (color.isTransparent())
         return;
 
-    const QColorProfile *colorProfile = nullptr;
+    const QColorTrcLut *colorProfile = nullptr;
 
     if (useGammaCorrection)
         colorProfile = QGuiApplicationPrivate::instance()->colorProfileForA8Text();
@@ -5830,7 +5830,7 @@ static inline QRgb rgbBlend(QRgb d, QRgb s, uint rgbAlpha)
 #endif
 }
 
-static inline void alphargbblend_generic(uint coverage, QRgba64 *dest, int x, const QRgba64 &srcLinear, const QRgba64 &src, const QColorProfile *colorProfile)
+static inline void alphargbblend_generic(uint coverage, QRgba64 *dest, int x, const QRgba64 &srcLinear, const QRgba64 &src, const QColorTrcLut *colorProfile)
 {
     if (coverage == 0xff000000) {
         // nothing
@@ -5852,7 +5852,7 @@ static inline void alphargbblend_generic(uint coverage, QRgba64 *dest, int x, co
     }
 }
 
-static inline void alphargbblend_argb32(quint32 *dst, uint coverage, const QRgba64 &srcLinear, quint32 src, const QColorProfile *colorProfile)
+static inline void alphargbblend_argb32(quint32 *dst, uint coverage, const QRgba64 &srcLinear, quint32 src, const QColorTrcLut *colorProfile)
 {
     if (coverage == 0xff000000) {
         // nothing
@@ -5877,7 +5877,7 @@ static void qt_alphargbblit_generic(QRasterBuffer *rasterBuffer,
     if (color.isTransparent())
         return;
 
-    const QColorProfile *colorProfile = nullptr;
+    const QColorTrcLut *colorProfile = nullptr;
 
     if (useGammaCorrection)
         colorProfile = QGuiApplicationPrivate::instance()->colorProfileForA32Text();
@@ -5954,7 +5954,7 @@ static void qt_alphargbblit_argb32(QRasterBuffer *rasterBuffer,
 
     const quint32 c = color.toArgb32();
 
-    const QColorProfile *colorProfile = nullptr;
+    const QColorTrcLut *colorProfile = nullptr;
 
     if (useGammaCorrection)
         colorProfile = QGuiApplicationPrivate::instance()->colorProfileForA32Text();
diff --git a/src/gui/painting/qicc.cpp b/src/gui/painting/qicc.cpp
new file mode 100644
index 0000000000..d88b005782
--- /dev/null
+++ b/src/gui/painting/qicc.cpp
@@ -0,0 +1,669 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qicc_p.h"
+
+#include <qbuffer.h>
+#include <qbytearray.h>
+#include <qdatastream.h>
+#include <qloggingcategory.h>
+#include <qendian.h>
+
+#include "qcolorspace_p.h"
+#include "qcolortrc_p.h"
+
+QT_BEGIN_NAMESPACE
+Q_LOGGING_CATEGORY(lcIcc, "qt.gui.icc")
+
+struct ICCProfileHeader
+{
+    quint32_be profileSize;
+
+    quint32_be preferredCmmType;
+
+    quint32_be profileVersion;
+    quint32_be profileClass;
+    quint32_be inputColorSpace;
+    quint32_be pcs;
+    quint32_be datetime[3];
+    quint32_be signature;
+    quint32_be platformSignature;
+    quint32_be flags;
+    quint32_be deviceManufacturer;
+    quint32_be deviceModel;
+    quint32_be deviceAttributes[2];
+
+    quint32_be renderingIntent;
+    qint32_be  illuminantXyz[3];
+
+    quint32_be creatorSignature;
+    quint32_be profileId[4];
+
+    quint32_be reserved[7];
+
+// Technically after the header, but easier to include here:
+    quint32_be tagCount;
+};
+
+constexpr quint32 IccTag(uchar a, uchar b, uchar c, uchar d)
+{
+    return (a << 24) | (b << 16) | (c << 8) | d;
+}
+
+enum class ProfileClass : quint32 {
+    Input       = IccTag('s', 'c', 'r', 'n'),
+    Display     = IccTag('m', 'n', 't', 'r'),
+    // Not supported:
+    Output      = IccTag('p', 'r', 't', 'r'),
+    ColorSpace  = IccTag('s', 'p', 'a', 'c'),
+};
+
+enum class Tag : quint32 {
+    acsp = IccTag('a', 'c', 's', 'p'),
+    RGB_ = IccTag('R', 'G', 'B', ' '),
+    XYZ_ = IccTag('X', 'Y', 'Z', ' '),
+    rXYZ = IccTag('r', 'X', 'Y', 'Z'),
+    gXYZ = IccTag('g', 'X', 'Y', 'Z'),
+    bXYZ = IccTag('b', 'X', 'Y', 'Z'),
+    rTRC = IccTag('r', 'T', 'R', 'C'),
+    gTRC = IccTag('g', 'T', 'R', 'C'),
+    bTRC = IccTag('b', 'T', 'R', 'C'),
+    A2B0 = IccTag('A', '2', 'B', '0'),
+    A2B1 = IccTag('A', '2', 'B', '1'),
+    B2A0 = IccTag('B', '2', 'A', '0'),
+    B2A1 = IccTag('B', '2', 'A', '1'),
+    desc = IccTag('d', 'e', 's', 'c'),
+    text = IccTag('t', 'e', 'x', 't'),
+    cprt = IccTag('c', 'p', 'r', 't'),
+    curv = IccTag('c', 'u', 'r', 'v'),
+    para = IccTag('p', 'a', 'r', 'a'),
+    wtpt = IccTag('w', 't', 'p', 't'),
+    bkpt = IccTag('b', 'k', 'p', 't'),
+    mft1 = IccTag('m', 'f', 't', '1'),
+    mft2 = IccTag('m', 'f', 't', '2'),
+    mAB_ = IccTag('m', 'A', 'B', ' '),
+    mBA_ = IccTag('m', 'B', 'A', ' '),
+    chad = IccTag('c', 'h', 'a', 'd'),
+    sf32 = IccTag('s', 'f', '3', '2'),
+
+    // Apple extensions for ICCv2:
+    aarg = IccTag('a', 'a', 'r', 'g'),
+    aagg = IccTag('a', 'a', 'g', 'g'),
+    aabg = IccTag('a', 'a', 'b', 'g'),
+};
+
+inline uint qHash(const Tag &key, uint seed = 0)
+{
+    return qHash(quint32(key), seed);
+}
+
+namespace QIcc {
+
+struct TagTableEntry
+{
+    quint32_be signature;
+    quint32_be offset;
+    quint32_be size;
+};
+
+struct GenericTagData {
+    quint32_be type;
+    quint32_be null;
+};
+
+struct XYZTagData : GenericTagData {
+    qint32_be fixedX;
+    qint32_be fixedY;
+    qint32_be fixedZ;
+};
+
+struct CurvTagData : GenericTagData {
+    quint32_be valueCount;
+    quint16_be value[1];
+};
+
+struct ParaTagData : GenericTagData {
+    quint16_be curveType;
+    quint16_be null2;
+    quint32_be parameter[1];
+};
+
+// For both mAB and mBA
+struct mABTagData : GenericTagData {
+    quint8 inputChannels;
+    quint8 outputChannels;
+    quint8 padding[2];
+    quint32_be bCurvesOffset;
+    quint32_be matrixOffset;
+    quint32_be mCurvesOffset;
+    quint32_be clutOffset;
+    quint32_be aCurvesOffset;
+};
+
+struct Sf32TagData : GenericTagData {
+    quint32_be value[1];
+};
+
+static int toFixedS1516(float x)
+{
+    return int(x * 65536.0f + 0.5f);
+}
+
+static float fromFixedS1516(int x)
+{
+    return x * (1.0f / 65536.0f);
+}
+
+QColorVector fromXyzData(const XYZTagData *xyz)
+{
+    const float x = fromFixedS1516(xyz->fixedX);
+    const float y = fromFixedS1516(xyz->fixedY);
+    const float z = fromFixedS1516(xyz->fixedZ);
+    qCDebug(lcIcc) << "XYZ_ " << x << y << z;
+
+    return QColorVector(x, y, z);
+}
+
+static bool isValidIccProfile(const ICCProfileHeader &header)
+{
+    if (header.signature != uint(Tag::acsp)) {
+        qCWarning(lcIcc, "Failed ICC signature test");
+        return false;
+    }
+    if (header.profileSize < (sizeof(ICCProfileHeader) + header.tagCount * sizeof(TagTableEntry))) {
+        qCWarning(lcIcc, "Failed basic size sanity");
+        return false;
+    }
+
+    if (header.profileClass != uint(ProfileClass::Input)
+        && header.profileClass != uint(ProfileClass::Display)) {
+        qCWarning(lcIcc, "Unsupported ICC profile class %x", quint32(header.profileClass));
+        return false;
+    }
+    if (header.inputColorSpace != 0x52474220 /* 'RGB '*/) {
+        qCWarning(lcIcc, "Unsupported ICC input color space %x", quint32(header.inputColorSpace));
+        return false;
+    }
+    if (header.pcs != 0x58595a20 /* 'XYZ '*/) {
+        // ### support PCSLAB
+        qCWarning(lcIcc, "Unsupported ICC profile connection space %x", quint32(header.pcs));
+        return false;
+    }
+
+    QColorVector illuminant;
+    illuminant.x = fromFixedS1516(header.illuminantXyz[0]);
+    illuminant.y = fromFixedS1516(header.illuminantXyz[1]);
+    illuminant.z = fromFixedS1516(header.illuminantXyz[2]);
+    if (illuminant != QColorVector::D50()) {
+        qCWarning(lcIcc, "Invalid ICC illuminant");
+        return false;
+    }
+
+    return true;
+}
+
+static int writeColorTrc(QDataStream &stream, const QColorTrc &trc)
+{
+    if (trc.isLinear()) {
+        stream << uint(Tag::curv) << uint(0);
+        stream << uint(0);
+        return 12;
+    }
+
+    if (trc.m_type == QColorTrc::Type::Function) {
+        const QColorTransferFunction &fun = trc.m_fun;
+        stream << uint(Tag::para) << uint(0);
+        if (fun.isGamma()) {
+            stream << ushort(0) << ushort(0);
+            stream << toFixedS1516(fun.m_g);
+            return 12 + 4;
+        }
+        bool type3 = qFuzzyIsNull(fun.m_e) && qFuzzyIsNull(fun.m_f);
+        stream << ushort(type3 ? 3 : 4) << ushort(0);
+        stream << toFixedS1516(fun.m_g);
+        stream << toFixedS1516(fun.m_a);
+        stream << toFixedS1516(fun.m_b);
+        stream << toFixedS1516(fun.m_c);
+        stream << toFixedS1516(fun.m_d);
+        if (type3)
+            return 12 + 5 * 4;
+        stream << toFixedS1516(fun.m_e);
+        stream << toFixedS1516(fun.m_f);
+        return 12 + 7 * 4;
+    }
+
+    Q_ASSERT(trc.m_type == QColorTrc::Type::Table);
+    stream << uint(Tag::curv) << uint(0);
+    stream << uint(trc.m_table.m_tableSize);
+    if (!trc.m_table.m_table16.isEmpty()) {
+        for (uint i = 0; i < trc.m_table.m_tableSize; ++i) {
+            stream << ushort(trc.m_table.m_table16[i]);
+        }
+    } else {
+        for (uint i = 0; i < trc.m_table.m_tableSize; ++i) {
+            stream << ushort(trc.m_table.m_table8[i] * 257U);
+        }
+    }
+    return 12 + 2 * trc.m_table.m_tableSize;
+}
+
+QByteArray toIccProfile(const QColorSpace &space)
+{
+    if (!space.isValid())
+        return QByteArray();
+
+    const QColorSpacePrivate *spaceDPtr = space.d_func();
+
+    constexpr int tagCount = 9;
+    constexpr uint profileDataOffset = 128 + 4 + 12 * tagCount;
+    constexpr uint variableTagTableOffsets = 128 + 4 + 12 * 5;
+    uint currentOffset = 0;
+    uint rTrcOffset, gTrcOffset, bTrcOffset;
+    uint rTrcSize, gTrcSize, bTrcSize;
+    uint descOffset, descSize;
+
+    QBuffer buffer;
+    buffer.open(QIODevice::WriteOnly);
+    QDataStream stream(&buffer);
+
+    // Profile header:
+    stream << uint(0); // Size, we will update this later
+    stream << uint(0);
+    stream << uint(0x02400000); // Version 2.4 (note we use 'para' from version 4)
+    stream << uint(ProfileClass::Display);
+    stream << uint(Tag::RGB_);
+    stream << uint(Tag::XYZ_);
+    stream << uint(0) << uint(0) << uint(0);
+    stream << uint(Tag::acsp);
+    stream << uint(0) << uint(0) << uint(0);
+    stream << uint(0) << uint(0) << uint(0);
+    stream << uint(1); // Rendering intent
+    stream << uint(0x0000f6d6); // D50 X
+    stream << uint(0x00010000); // D50 Y
+    stream << uint(0x0000d32d); // D50 Z
+    stream << IccTag('Q','t', QT_VERSION_MAJOR, QT_VERSION_MINOR);
+    stream << uint(0) << uint(0) << uint(0) << uint(0);
+    stream << uint(0) << uint(0) << uint(0) << uint(0) << uint(0) << uint(0) << uint(0);
+
+    // Tag table:
+    stream << uint(tagCount);
+    stream << uint(Tag::rXYZ) << uint(profileDataOffset + 00) << uint(20);
+    stream << uint(Tag::gXYZ) << uint(profileDataOffset + 20) << uint(20);
+    stream << uint(Tag::bXYZ) << uint(profileDataOffset + 40) << uint(20);
+    stream << uint(Tag::wtpt) << uint(profileDataOffset + 60) << uint(20);
+    stream << uint(Tag::cprt) << uint(profileDataOffset + 80) << uint(12);
+    // From here the offset and size will be updated later:
+    stream << uint(Tag::rTRC) << uint(0) << uint(0);
+    stream << uint(Tag::gTRC) << uint(0) << uint(0);
+    stream << uint(Tag::bTRC) << uint(0) << uint(0);
+    stream << uint(Tag::desc) << uint(0) << uint(0);
+    // TODO: consider adding 'chad' tag (required in ICC >=4 when we have non-D50 whitepoint)
+    currentOffset = profileDataOffset;
+
+    // Tag data:
+    stream << uint(Tag::XYZ_) << uint(0);
+    stream << toFixedS1516(spaceDPtr->toXyz.r.x);
+    stream << toFixedS1516(spaceDPtr->toXyz.r.y);
+    stream << toFixedS1516(spaceDPtr->toXyz.r.z);
+    stream << uint(Tag::XYZ_) << uint(0);
+    stream << toFixedS1516(spaceDPtr->toXyz.g.x);
+    stream << toFixedS1516(spaceDPtr->toXyz.g.y);
+    stream << toFixedS1516(spaceDPtr->toXyz.g.z);
+    stream << uint(Tag::XYZ_) << uint(0);
+    stream << toFixedS1516(spaceDPtr->toXyz.b.x);
+    stream << toFixedS1516(spaceDPtr->toXyz.b.y);
+    stream << toFixedS1516(spaceDPtr->toXyz.b.z);
+    stream << uint(Tag::XYZ_) << uint(0);
+    stream << toFixedS1516(spaceDPtr->whitePoint.x);
+    stream << toFixedS1516(spaceDPtr->whitePoint.y);
+    stream << toFixedS1516(spaceDPtr->whitePoint.z);
+    stream << uint(Tag::text) << uint(0);
+    stream << uint(IccTag('N', '/', 'A', '\0'));
+    currentOffset += 92;
+
+    // From now on the data is variable sized:
+    rTrcOffset = currentOffset;
+    rTrcSize = writeColorTrc(stream, spaceDPtr->trc[0]);
+    currentOffset += rTrcSize;
+    if (spaceDPtr->trc[0] == spaceDPtr->trc[1]) {
+        gTrcOffset = rTrcOffset;
+        gTrcSize = rTrcSize;
+    } else {
+        gTrcOffset = currentOffset;
+        gTrcSize = writeColorTrc(stream, spaceDPtr->trc[1]);
+        currentOffset += gTrcSize;
+    }
+    if (spaceDPtr->trc[0] == spaceDPtr->trc[2]) {
+        bTrcOffset = rTrcOffset;
+        bTrcSize = rTrcSize;
+    } else {
+        bTrcOffset = currentOffset;
+        bTrcSize = writeColorTrc(stream, spaceDPtr->trc[2]);
+        currentOffset += bTrcSize;
+    }
+
+    descOffset = currentOffset;
+    QByteArray description = spaceDPtr->description.toUtf8();
+    stream << uint(Tag::desc) << uint(0);
+    stream << uint(description.size() + 1);
+    stream.writeRawData(description.constData(), description.size() + 1);
+    stream << uint(0) << uint(0);
+    stream << ushort(0) << uchar(0);
+    QByteArray macdesc(67, '\0');
+    stream.writeRawData(macdesc.constData(), 67);
+    descSize = 90 + description.size() + 1;
+    currentOffset += descSize;
+
+    buffer.close();
+    QByteArray iccProfile = buffer.buffer();
+    // Now write final size
+    *(quint32_be *)iccProfile.data() = iccProfile.size();
+    // And the final indices and sizes of variable size tags:
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 4) = rTrcOffset;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 8) = rTrcSize;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 12 + 4) = gTrcOffset;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 12 + 8) = gTrcSize;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 2 * 12 + 4) = bTrcOffset;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 2 * 12 + 8) = bTrcSize;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 3 * 12 + 4) = descOffset;
+    *(quint32_be *)(iccProfile.data() + variableTagTableOffsets + 3 * 12 + 8) = descSize;
+
+#if !defined(QT_NO_DEBUG) || defined(QT_FORCE_ASSERTS)
+    const ICCProfileHeader *iccHeader = (const ICCProfileHeader *)iccProfile.constData();
+    Q_ASSERT(qsizetype(iccHeader->profileSize) == qsizetype(iccProfile.size()));
+    Q_ASSERT(isValidIccProfile(*iccHeader));
+#endif
+
+    return iccProfile;
+}
+
+bool parseTRC(const GenericTagData *trcData, QColorTrc &gamma)
+{
+    if (trcData->type == quint32(Tag::curv)) {
+        const CurvTagData *curv = reinterpret_cast<const CurvTagData *>(trcData);
+        qCDebug(lcIcc) << "curv" << uint(curv->valueCount);
+        if (curv->valueCount == 0) {
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction(); // Linear
+        } else if (curv->valueCount == 1) {
+            float g = curv->value[0] * (1.0f / 256.0f);
+            qCDebug(lcIcc) << g;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction::fromGamma(g);
+        } else {
+            QVector<quint16> tabl;
+            tabl.resize(curv->valueCount);
+            for (uint i = 0; i < curv->valueCount; ++i)
+                tabl[i] = curv->value[i];
+            QColorTransferTable table = QColorTransferTable(curv->valueCount, std::move(tabl));
+            QColorTransferFunction curve;
+            if (!table.asColorTransferFunction(&curve)) {
+                gamma.m_type = QColorTrc::Type::Table;
+                gamma.m_table = table;
+            } else {
+                qCDebug(lcIcc) << "Detected curv table as function";
+                gamma.m_type = QColorTrc::Type::Function;
+                gamma.m_fun = curve;
+            }
+        }
+        return true;
+    }
+    if (trcData->type == quint32(Tag::para)) {
+        const ParaTagData *para = reinterpret_cast<const ParaTagData *>(trcData);
+        qCDebug(lcIcc) << "para" << uint(para->curveType);
+        switch (para->curveType) {
+        case 0: {
+            float g = fromFixedS1516(para->parameter[0]);
+            qCDebug(lcIcc) << g;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction::fromGamma(g);
+            break;
+        }
+        case 1: {
+            float g = fromFixedS1516(para->parameter[0]);
+            float a = fromFixedS1516(para->parameter[1]);
+            float b = fromFixedS1516(para->parameter[2]);
+            float d = -b / a;
+            qCDebug(lcIcc) << g << a << b;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction(a, b, 0.0f, d, 0.0f, 0.0f, g);
+            break;
+        }
+        case 2: {
+            float g = fromFixedS1516(para->parameter[0]);
+            float a = fromFixedS1516(para->parameter[1]);
+            float b = fromFixedS1516(para->parameter[2]);
+            float c = fromFixedS1516(para->parameter[3]);
+            float d = -b / a;
+            qCDebug(lcIcc) << g << a << b << c;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction(a, b, 0.0f, d, c, c, g);
+            break;
+        }
+        case 3: {
+            float g = fromFixedS1516(para->parameter[0]);
+            float a = fromFixedS1516(para->parameter[1]);
+            float b = fromFixedS1516(para->parameter[2]);
+            float c = fromFixedS1516(para->parameter[3]);
+            float d = fromFixedS1516(para->parameter[4]);
+            qCDebug(lcIcc) << g << a << b << c << d;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction(a, b, c, d, 0.0f, 0.0f, g);
+            break;
+        }
+        case 4: {
+            float g = fromFixedS1516(para->parameter[0]);
+            float a = fromFixedS1516(para->parameter[1]);
+            float b = fromFixedS1516(para->parameter[2]);
+            float c = fromFixedS1516(para->parameter[3]);
+            float d = fromFixedS1516(para->parameter[4]);
+            float e = fromFixedS1516(para->parameter[5]);
+            float f = fromFixedS1516(para->parameter[6]);
+            qCDebug(lcIcc) << g << a << b << c << d << e << f;
+            gamma.m_type = QColorTrc::Type::Function;
+            gamma.m_fun = QColorTransferFunction(a, b, c, d, e, f, g);
+            break;
+        }
+        default:
+            qCWarning(lcIcc)  << "Unknown para type" << uint(para->curveType);
+            return false;
+        }
+        return true;
+    }
+    qCWarning(lcIcc) << "Invalid TRC data type";
+    return false;
+}
+
+bool fromIccProfile(const QByteArray &data, QColorSpace *colorSpace)
+{
+    if (data.size() < qsizetype(sizeof(ICCProfileHeader))) {
+        qCWarning(lcIcc) << "fromIccProfile: failed size sanity 1";
+        return false;
+    }
+    const ICCProfileHeader *header = (const ICCProfileHeader *)data.constData();
+    if (!isValidIccProfile(*header)) {
+        qCWarning(lcIcc) << "fromIccProfile: failed general sanity check";
+        return false;
+    }
+    if (qsizetype(header->profileSize) > data.size()) {
+        qCWarning(lcIcc) << "fromIccProfile: failed size sanity 2";
+        return false;
+    }
+
+    // Read tag index
+    const TagTableEntry *tagTable = (const TagTableEntry *)(data.constData() + sizeof(ICCProfileHeader));
+    const qsizetype offsetToData = sizeof(ICCProfileHeader) + header->tagCount * sizeof(TagTableEntry);
+
+    QHash<Tag, quint32> tagIndex;
+    for (uint i = 0; i < header->tagCount; ++i) {
+        // Sanity check tag sizes and offsets:
+        if (qsizetype(tagTable[i].offset) < offsetToData) {
+            qCWarning(lcIcc) << "fromIccProfile: failed tag offset sanity 1";
+            return false;
+        }
+        // Checked separately from (+ size) to handle overflow.
+        if (tagTable[i].offset > header->profileSize) {
+            qCWarning(lcIcc) << "fromIccProfile: failed tag offset sanity 2";
+            return false;
+        }
+        if ((tagTable[i].offset + tagTable[i].size) > header->profileSize) {
+            qCWarning(lcIcc) << "fromIccProfile: failed tag offset + size sanity";
+            return false;
+        }
+//        printf("'%4s' %d %d\n", (const char *)&tagTable[i].signature,
+//                                quint32(tagTable[i].offset),
+//                                quint32(tagTable[i].size));
+        tagIndex.insert(Tag(quint32(tagTable[i].signature)), tagTable[i].offset);
+    }
+    // Check the profile is three-component matrix based (what we currently support):
+    if (!tagIndex.contains(Tag::rXYZ) || !tagIndex.contains(Tag::gXYZ) || !tagIndex.contains(Tag::bXYZ) ||
+        !tagIndex.contains(Tag::rTRC) || !tagIndex.contains(Tag::gTRC) || !tagIndex.contains(Tag::bTRC) ||
+        !tagIndex.contains(Tag::wtpt)) {
+        qCWarning(lcIcc) << "fromIccProfile: Unsupported ICC profile - not three component matrix based";
+        return false;
+    }
+
+    // Parse XYZ tags
+    const XYZTagData *rXyz = (const XYZTagData *)(data.constData() + tagIndex[Tag::rXYZ]);
+    const XYZTagData *gXyz = (const XYZTagData *)(data.constData() + tagIndex[Tag::gXYZ]);
+    const XYZTagData *bXyz = (const XYZTagData *)(data.constData() + tagIndex[Tag::bXYZ]);
+    const XYZTagData *wXyz = (const XYZTagData *)(data.constData() + tagIndex[Tag::wtpt]);
+    if (rXyz->type != quint32(Tag::XYZ_) || gXyz->type != quint32(Tag::XYZ_) ||
+        wXyz->type != quint32(Tag::XYZ_) || wXyz->type != quint32(Tag::XYZ_)) {
+        qCWarning(lcIcc) << "fromIccProfile: Bad XYZ data type";
+        return false;
+    }
+    QColorSpacePrivate *colorspaceDPtr = colorSpace->d_func();
+
+    colorspaceDPtr->toXyz.r = fromXyzData(rXyz);
+    colorspaceDPtr->toXyz.g = fromXyzData(gXyz);
+    colorspaceDPtr->toXyz.b = fromXyzData(bXyz);
+    QColorVector whitePoint = fromXyzData(wXyz);
+    colorspaceDPtr->whitePoint = whitePoint;
+
+    colorspaceDPtr->gamut = QColorSpace::Gamut::Custom;
+    if (colorspaceDPtr->toXyz == QColorMatrix::toXyzFromSRgb()) {
+        qCDebug(lcIcc) << "fromIccProfile: sRGB gamut detected";
+        colorspaceDPtr->gamut = QColorSpace::Gamut::SRgb;
+    } else if (colorspaceDPtr->toXyz == QColorMatrix::toXyzFromAdobeRgb()) {
+        qCDebug(lcIcc) << "fromIccProfile: Adobe RGB gamut detected";
+        colorspaceDPtr->gamut = QColorSpace::Gamut::AdobeRgb;
+    } else if (colorspaceDPtr->toXyz == QColorMatrix::toXyzFromDciP3D65()) {
+        qCDebug(lcIcc) << "fromIccProfile: DCI-P3 D65 gamut detected";
+        colorspaceDPtr->gamut = QColorSpace::Gamut::DciP3D65;
+    } else if (colorspaceDPtr->toXyz == QColorMatrix::toXyzFromBt2020()) {
+        qCDebug(lcIcc) << "fromIccProfile: BT.2020 gamut detected";
+        colorspaceDPtr->gamut = QColorSpace::Gamut::Bt2020;
+    }
+    if (colorspaceDPtr->toXyz == QColorMatrix::toXyzFromProPhotoRgb()) {
+        qCDebug(lcIcc) << "fromIccProfile: ProPhoto RGB gamut detected";
+        colorspaceDPtr->gamut = QColorSpace::Gamut::ProPhotoRgb;
+    }
+    // Reset the matrix to our canonical values:
+    if (colorspaceDPtr->gamut != QColorSpace::Gamut::Custom)
+        colorspaceDPtr->setToXyzMatrix();
+
+    // Parse TRC tags
+    const GenericTagData *rTrc;
+    const GenericTagData *gTrc;
+    const GenericTagData *bTrc;
+    if (tagIndex.contains(Tag::aarg) && tagIndex.contains(Tag::aagg) && tagIndex.contains(Tag::aabg)) {
+        // Apple extension for parametric version of TRCs in ICCv2:
+        rTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::aarg]);
+        gTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::aagg]);
+        bTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::aabg]);
+    } else {
+        rTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::rTRC]);
+        gTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::gTRC]);
+        bTrc = (const GenericTagData *)(data.constData() + tagIndex[Tag::bTRC]);
+    }
+
+    QColorTrc rCurve;
+    QColorTrc gCurve;
+    QColorTrc bCurve;
+    if (!parseTRC(rTrc, rCurve))
+        return false;
+    if (!parseTRC(gTrc, gCurve))
+        return false;
+    if (!parseTRC(bTrc, bCurve))
+        return false;
+    if (rCurve == gCurve && gCurve == bCurve && rCurve.m_type == QColorTrc::Type::Function) {
+        if (rCurve.m_fun.isLinear()) {
+            qCDebug(lcIcc) << "fromIccProfile: Linear gamma detected";
+            colorspaceDPtr->trc[0] = QColorTransferFunction();
+            colorspaceDPtr->transferFunction = QColorSpace::TransferFunction::Linear;
+            colorspaceDPtr->gamma = 1.0f;
+        } else if (rCurve.m_fun.isGamma()) {
+            qCDebug(lcIcc) << "fromIccProfile: Simple gamma detected";
+            colorspaceDPtr->trc[0] = QColorTransferFunction::fromGamma(rCurve.m_fun.m_g);
+            colorspaceDPtr->transferFunction = QColorSpace::TransferFunction::Gamma;
+            colorspaceDPtr->gamma = rCurve.m_fun.m_g;
+        } else if (rCurve.m_fun.isSRgb()) {
+            qCDebug(lcIcc) << "fromIccProfile: sRGB gamma detected";
+            colorspaceDPtr->trc[0] = QColorTransferFunction::fromSRgb();
+            colorspaceDPtr->transferFunction = QColorSpace::TransferFunction::SRgb;
+        } else {
+            colorspaceDPtr->trc[0] = rCurve;
+            colorspaceDPtr->transferFunction = QColorSpace::TransferFunction::Custom;
+        }
+
+        colorspaceDPtr->trc[1] = colorspaceDPtr->trc[0];
+        colorspaceDPtr->trc[2] = colorspaceDPtr->trc[0];
+    } else {
+        colorspaceDPtr->trc[0] = rCurve;
+        colorspaceDPtr->trc[1] = gCurve;
+        colorspaceDPtr->trc[2] = bCurve;
+        colorspaceDPtr->transferFunction = QColorSpace::TransferFunction::Custom;
+    }
+
+    // FIXME: try to parse the description..
+
+    if (!colorspaceDPtr->identifyColorSpace())
+        colorspaceDPtr->id = QColorSpace::Unknown;
+    else
+        qCDebug(lcIcc) << "fromIccProfile: Named colorspace detected: " << colorSpace->colorSpaceId();
+
+    colorspaceDPtr->iccProfile = data;
+
+    return true;
+}
+
+} // namespace QIcc
+
+QT_END_NAMESPACE
diff --git a/src/gui/painting/qicc_p.h b/src/gui/painting/qicc_p.h
new file mode 100644
index 0000000000..c3220391f4
--- /dev/null
+++ b/src/gui/painting/qicc_p.h
@@ -0,0 +1,70 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QICC_P_H
+#define QICC_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/qbytearray.h>
+#include <QtGui/qtguiglobal.h>
+
+QT_BEGIN_NAMESPACE
+
+class QColorSpace;
+
+namespace QIcc {
+
+Q_GUI_EXPORT bool fromIccProfile(const QByteArray &data, QColorSpace *colorSpace);
+Q_GUI_EXPORT QByteArray toIccProfile(const QColorSpace &space);
+
+}
+
+QT_END_NAMESPACE
+
+#endif // QICC_P_H
diff --git a/src/gui/painting/qpainter_p.h b/src/gui/painting/qpainter_p.h
index 930180e9fa..9857a59070 100644
--- a/src/gui/painting/qpainter_p.h
+++ b/src/gui/painting/qpainter_p.h
@@ -54,6 +54,8 @@
 #include <QtCore/qvarlengtharray.h>
 #include <QtGui/private/qtguiglobal_p.h>
 #include "QtGui/qbrush.h"
+#include "QtGui/qcolorspace.h"
+#include "QtGui/qcolortransform.h"
 #include "QtGui/qfont.h"
 #include "QtGui/qpen.h"
 #include "QtGui/qregion.h"