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Diffstat (limited to 'src/gui/painting/qcolortransfertable_p.h')
| -rw-r--r-- | src/gui/painting/qcolortransfertable_p.h | 245 |
1 files changed, 245 insertions, 0 deletions
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 |