Add test of QColorTransform

Before it was only tested indirectly as part of the qcolorspace
tests. This also fixes a rounding for maximum RGB64 values.

Pick-to: 6.3
Change-Id: I6106e662c0f9d00c0b3a0c13213cb051ea39e14e
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

4 files changed, 238 insertions, 1 deletions

diff --git a/src/gui/painting/qcolortransform.cpp b/src/gui/painting/qcolortransform.cpp
index ff7229e060..71b07f30a5 100644
--- a/src/gui/painting/qcolortransform.cpp
+++ b/src/gui/painting/qcolortransform.cpp
@@ -163,7 +163,7 @@ QRgba64 QColorTransform::map(QRgba64 rgba64) const
         c.z = d->colorSpaceOut->trc[2].applyInverse(c.z);
     }
 
-    return QRgba64::fromRgba64(c.x * 65535, c.y * 65535, c.z * 65535, rgba64.alpha());
+    return QRgba64::fromRgba64(c.x * 65535.f + 0.5f, c.y * 65535.f + 0.5f, c.z * 65535.f + 0.5f, rgba64.alpha());
 }
 
 /*!
diff --git a/tests/auto/gui/painting/CMakeLists.txt b/tests/auto/gui/painting/CMakeLists.txt
index 4f933139ca..9aa99ea878 100644
--- a/tests/auto/gui/painting/CMakeLists.txt
+++ b/tests/auto/gui/painting/CMakeLists.txt
@@ -17,6 +17,7 @@ add_subdirectory(qpolygon)
 # QTBUG-87669 # special case
 if(NOT ANDROID)
     add_subdirectory(qcolorspace)
+    add_subdirectory(qcolortransform)
 endif()
 if(QT_FEATURE_private_tests)
     add_subdirectory(qpathclipper)
diff --git a/tests/auto/gui/painting/qcolortransform/CMakeLists.txt b/tests/auto/gui/painting/qcolortransform/CMakeLists.txt
new file mode 100644
index 0000000000..008ac92905
--- /dev/null
+++ b/tests/auto/gui/painting/qcolortransform/CMakeLists.txt
@@ -0,0 +1,10 @@
+#####################################################################
+## tst_qcolortransform Test:
+#####################################################################
+
+qt_internal_add_test(tst_qcolortransform
+    SOURCES
+        tst_qcolortransform.cpp
+    PUBLIC_LIBRARIES
+        Qt::Gui
+)
diff --git a/tests/auto/gui/painting/qcolortransform/tst_qcolortransform.cpp b/tests/auto/gui/painting/qcolortransform/tst_qcolortransform.cpp
new file mode 100644
index 0000000000..c09d3fc11e
--- /dev/null
+++ b/tests/auto/gui/painting/qcolortransform/tst_qcolortransform.cpp
@@ -0,0 +1,226 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** 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 General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** 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-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <QTest>
+
+#include <qcolorspace.h>
+#include <qcolortransform.h>
+
+class tst_QColorTransform : public QObject
+{
+    Q_OBJECT
+
+public:
+    tst_QColorTransform();
+
+private slots:
+    void mapRGB32_data();
+    void mapRGB32();
+    void mapRGB64_data();
+    void mapRGB64();
+    void mapQColor_data();
+    void mapQColor();
+};
+
+tst_QColorTransform::tst_QColorTransform()
+{ }
+
+
+void tst_QColorTransform::mapRGB32_data()
+{
+    QTest::addColumn<QColorTransform>("transform");
+    QTest::addColumn<bool>("isIdentity");
+    QTest::addColumn<bool>("sharesRed");
+
+    QTest::newRow("default") << QColorTransform() << true << true;
+    QTest::newRow("sRGB to Linear") << QColorSpace(QColorSpace::SRgb).transformationToColorSpace(QColorSpace::SRgbLinear) << false << true;
+    QTest::newRow("AdobeRGB to sRGB") << QColorSpace(QColorSpace::AdobeRgb).transformationToColorSpace(QColorSpace::SRgb) << false << true;
+    QTest::newRow("Linear AdobeRGB to Linear sRGB")
+        << QColorSpace(QColorSpace::AdobeRgb).withTransferFunction(QColorSpace::TransferFunction::Linear).transformationToColorSpace(
+            QColorSpace::SRgb)
+        << false << true;
+    QTest::newRow("sRgb to AdobeRGB") << QColorSpace(QColorSpace::SRgb).transformationToColorSpace(QColorSpace::AdobeRgb) << false << true;
+    QTest::newRow("DP3 to sRGB") << QColorSpace(QColorSpace::DisplayP3).transformationToColorSpace(QColorSpace::SRgb) << false << false;
+    QTest::newRow("DP3 to Linear DP3")
+        << QColorSpace(QColorSpace::DisplayP3).transformationToColorSpace(
+            QColorSpace(QColorSpace::DisplayP3).withTransferFunction(QColorSpace::TransferFunction::Linear))
+        << false << false;
+    QTest::newRow("Linear DP3 to Linear sRGB")
+        << QColorSpace(QColorSpace::DisplayP3).withTransferFunction(QColorSpace::TransferFunction::Linear).transformationToColorSpace(
+            QColorSpace::SRgb)
+        << false << false;
+}
+
+void tst_QColorTransform::mapRGB32()
+{
+    QFETCH(QColorTransform, transform);
+    QFETCH(bool, isIdentity);
+    QFETCH(bool, sharesRed);
+    // Do basic sanity tests of conversions between similar sane color spaces
+
+    QRgb testColor = qRgb(32, 64, 128);
+    QRgb result = transform.map(testColor);
+    QVERIFY(qRed(result) < qGreen(result));
+    QVERIFY(qGreen(result) < qBlue(result));
+    QCOMPARE(qAlpha(result), 255);
+    if (isIdentity)
+        QVERIFY(result == testColor);
+    else
+        QVERIFY(result != testColor);
+
+    testColor = qRgb(128, 64, 32);
+    result = transform.map(testColor);
+    QVERIFY(qRed(result) > qGreen(result));
+    QVERIFY(qGreen(result) > qBlue(result));
+    QCOMPARE(qAlpha(result), 255);
+    if (isIdentity)
+        QVERIFY(result == testColor);
+    else
+        QVERIFY(result != testColor);
+
+    testColor = qRgba(15, 31, 63, 128);
+    result = transform.map(testColor);
+    QVERIFY(qRed(result) < qGreen(result));
+    QVERIFY(qGreen(result) < qBlue(result));
+    QCOMPARE(qAlpha(result), 128);
+    if (isIdentity)
+        QVERIFY(result == testColor);
+    else
+        QVERIFY(result != testColor);
+
+    testColor = qRgb(0, 0, 0);
+    result = transform.map(testColor);
+    QCOMPARE(qRed(result), 0);
+    QCOMPARE(qGreen(result), 0);
+    QCOMPARE(qBlue(result), 0);
+    QCOMPARE(qAlpha(result), 255);
+
+    testColor = qRgb(255, 255, 255);
+    result = transform.map(testColor);
+    QCOMPARE(qRed(result), 255);
+    QCOMPARE(qGreen(result), 255);
+    QCOMPARE(qBlue(result), 255);
+    QCOMPARE(qAlpha(result), 255);
+
+    testColor = qRgb(255, 255, 0);
+    result = transform.map(testColor);
+    QCOMPARE(qAlpha(result), 255);
+    if (sharesRed)
+        QCOMPARE(qRed(result), 255);
+
+    testColor = qRgb(0, 255, 255);
+    result = transform.map(testColor);
+    QCOMPARE(qBlue(result), 255);
+    QCOMPARE(qAlpha(result), 255);
+}
+
+void tst_QColorTransform::mapRGB64_data()
+{
+    mapRGB32_data();
+}
+
+void tst_QColorTransform::mapRGB64()
+{
+    QFETCH(QColorTransform, transform);
+    QFETCH(bool, isIdentity);
+    QFETCH(bool, sharesRed);
+
+    QRgba64 testColor = QRgba64::fromRgba(128, 64, 32, 255);
+    QRgba64 result = transform.map(testColor);
+    QVERIFY(result.red() > result.green());
+    QVERIFY(result.green() > result.blue());
+    QCOMPARE(result.alpha(), 0xffff);
+    if (isIdentity)
+        QVERIFY(result == testColor);
+    else
+        QVERIFY(result != testColor);
+
+    testColor = QRgba64::fromRgba64(0, 0, 0, 0xffff);
+    result = transform.map(testColor);
+    QCOMPARE(result, testColor);
+
+    testColor = QRgba64::fromRgba64(0xffff, 0xffff, 0xffff, 0xffff);
+    result = transform.map(testColor);
+    QCOMPARE(result, testColor);
+
+    testColor = QRgba64::fromRgba64(0xffff, 0xffff, 0, 0xffff);
+    result = transform.map(testColor);
+    QCOMPARE(result.alpha(), 0xffff);
+    if (sharesRed)
+        QCOMPARE(result.red(), 0xffff);
+
+    testColor = QRgba64::fromRgba64(0, 0xffff, 0xffff, 0xffff);
+    result = transform.map(testColor);
+    QCOMPARE(result.blue(), 0xffff);
+    QCOMPARE(result.alpha(), 0xffff);
+}
+
+void tst_QColorTransform::mapQColor_data()
+{
+    mapRGB32_data();
+}
+
+void tst_QColorTransform::mapQColor()
+{
+    QFETCH(QColorTransform, transform);
+    QFETCH(bool, isIdentity);
+    QFETCH(bool, sharesRed);
+
+    QColor testColor(32, 64, 128);
+    QColor result = transform.map(testColor);
+    QVERIFY(result.redF() < result.greenF());
+    QVERIFY(result.greenF() < result.blueF());
+    QCOMPARE(result.alphaF(), 1.0f);
+    if (isIdentity)
+        QVERIFY(result == testColor);
+    else
+        QVERIFY(result != testColor);
+
+    testColor = Qt::black;
+    result = transform.map(testColor);
+    QCOMPARE(result, testColor);
+
+    testColor = Qt::white;
+    result = transform.map(testColor);
+    QCOMPARE(result, testColor);
+
+    testColor = QColor(255, 255, 0);
+    result = transform.map(testColor);
+    QCOMPARE(result.alphaF(), 1);
+    if (sharesRed)
+        QVERIFY(result.redF() >= 1.0f);
+
+    testColor = QColor(0, 255, 255);
+    result = transform.map(testColor);
+    QCOMPARE(result.alphaF(), 1.0f);
+    QVERIFY(result.blueF() >= 1.0f);
+}
+
+QTEST_MAIN(tst_QColorTransform)
+#include "tst_qcolortransform.moc"