Solid and gradients in high color accuracy

This patch updates the internal color precisions of solids and
gradients to 16bit per color. This makes it possible to render
at higher precision on non-premultiplied ARGB32, the RGB30
formats and any other hi-color formats if more are added.

[ChangeLog][QtGui][Painting] Internal precision of solids and gradients
is now up to 16bit per color.

Change-Id: Ieae5468bd6de1f56adfa4cb9fa966faf2ed824fd
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

2 files changed, 83 insertions, 35 deletions

diff --git a/tests/auto/gui/painting/qpainter/qpainter.pro b/tests/auto/gui/painting/qpainter/qpainter.pro
index 7e9d438e1b..e90b516ef2 100644
--- a/tests/auto/gui/painting/qpainter/qpainter.pro
+++ b/tests/auto/gui/painting/qpainter/qpainter.pro
@@ -2,7 +2,7 @@ CONFIG += testcase
 CONFIG += parallel_test
 TARGET = tst_qpainter
 
-QT += testlib
+QT += testlib gui-private core-private
 qtHaveModule(widgets): QT += widgets widgets-private
 
 SOURCES  += tst_qpainter.cpp
diff --git a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
index 6582755aec..10b79fdd0f 100644
--- a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
+++ b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
@@ -53,6 +53,7 @@
 #endif
 #include <qpixmap.h>
 
+#include <private/qdrawhelper_p.h>
 #include <qpainter.h>
 
 #ifndef QT_NO_WIDGETS
@@ -125,8 +126,12 @@ private slots:
     void fillRect3();
     void fillRect4_data() { fillRect2_data(); }
     void fillRect4();
+    void fillRectNonPremul_data();
     void fillRectNonPremul();
 
+    void fillRectRGB30_data();
+    void fillRectRGB30();
+
     void drawEllipse_data();
     void drawEllipse();
     void drawClippedEllipse_data();
@@ -1245,22 +1250,87 @@ void tst_QPainter::fillRect4()
     QCOMPARE(image, expected);
 }
 
+void tst_QPainter::fillRectNonPremul_data()
+{
+    QTest::addColumn<QImage::Format>("format");
+    QTest::addColumn<uint>("color");
+
+    QTest::newRow("argb32 7f1f3f7f") << QImage::Format_ARGB32 << qRgba(31, 63, 127, 127);
+    QTest::newRow("rgba8888 7f1f3f7f") << QImage::Format_RGBA8888 << qRgba(31, 63, 127, 127);
+
+    QTest::newRow("argb32 3f1f3f7f") << QImage::Format_ARGB32 << qRgba(31, 63, 127, 63);
+    QTest::newRow("rgba8888 3f1f3f7f") << QImage::Format_RGBA8888 << qRgba(31, 63, 127, 63);
+
+    QTest::newRow("argb32 070375f4") << QImage::Format_ARGB32 << qRgba(3, 117, 244, 7);
+    QTest::newRow("rgba8888 070375f4") << QImage::Format_RGBA8888 << qRgba(3, 117, 244, 7);
+
+    QTest::newRow("argb32 0301fe0c") << QImage::Format_ARGB32 << qRgba(1, 254, 12, 3);
+    QTest::newRow("rgba8888 0301fe0c") << QImage::Format_RGBA8888 << qRgba(1, 254, 12, 3);
+
+    QTest::newRow("argb32 01804010") << QImage::Format_ARGB32 << qRgba(128, 64, 32, 1);
+    QTest::newRow("rgba8888 01804010") << QImage::Format_RGBA8888 << qRgba(128, 64, 32, 1);
+}
+
 void tst_QPainter::fillRectNonPremul()
 {
-    QImage img1(1, 1, QImage::Format_ARGB32);
-    QImage img2(1, 1, QImage::Format_RGBA8888);
+    QFETCH(QImage::Format, format);
+    QFETCH(uint, color);
 
-    QPainter p1(&img1);
-    QPainter p2(&img2);
+    QImage image(1, 1, format);
+    QRectF rect(0, 0, 1, 1);
+
+    // Fill with CompositionMode_SourceOver tests blend_color
+    image.fill(Qt::transparent);
+    QPainter painter(&image);
+    painter.fillRect(rect, QColor::fromRgba(color));
+    painter.end();
+
+    // Fill with CompositionMode_Source tests rectfill.
+    painter.begin(&image);
+    painter.setCompositionMode(QPainter::CompositionMode_Source);
+    painter.fillRect(rect, QColor::fromRgba(color));
+    painter.end();
+
+    QRgb p = image.pixel(0, 0);
+    QCOMPARE(qAlpha(p), qAlpha(color));
+    QVERIFY(qAbs(qRed(p)-qRed(color)) <= 1);
+    QVERIFY(qAbs(qGreen(p)-qGreen(color)) <= 1);
+    QVERIFY(qAbs(qBlue(p)-qBlue(color)) <= 1);
+}
+
+void tst_QPainter::fillRectRGB30_data()
+{
+    QTest::addColumn<uint>("color");
 
+    QTest::newRow("17|43|259") << (0xc0000000 | (17 << 20) | (43 << 10) | 259);
+    QTest::newRow("2|33|444") << (0xc0000000 | (2 << 20) | (33 << 10) | 444);
+    QTest::newRow("1000|1000|1000") << (0xc0000000 | (1000 << 20) | (1000 << 10) | 1000);
+}
+
+void tst_QPainter::fillRectRGB30()
+{
+    QFETCH(uint, color);
     QRectF rect(0, 0, 1, 1);
-    p1.fillRect(rect, qRgba(31, 63, 127, 127));
-    p2.fillRect(rect, qRgba(31, 63, 127, 127));
 
-    p1.end();
-    p2.end();
+    // Fill with CompositionMode_SourceOver tests blend_color
+    QImage image1(1, 1, QImage::Format_A2BGR30_Premultiplied);
+    image1.fill(Qt::transparent);
+    QPainter painter(&image1);
+    painter.fillRect(rect, QColor::fromRgba64(qConvertA2rgb30ToRgb64<PixelOrderBGR>(color)));
+    painter.end();
 
-    QCOMPARE(img1.pixel(0, 0), img2.pixel(0,0));
+    uint pixel1 = ((const uint*)(image1.bits()))[0];
+    QCOMPARE(pixel1, color);
+
+    // Fill with CompositionMode_Source tests rectfill.
+    QImage image2(1, 1, QImage::Format_RGB30);
+    painter.begin(&image2);
+    painter.setCompositionMode(QPainter::CompositionMode_Source);
+    painter.fillRect(rect, QColor::fromRgba64(qConvertA2rgb30ToRgb64<PixelOrderRGB>(color)));
+    painter.end();
+
+    uint pixel2 = ((const uint*)(image2.bits()))[0];
+    QCOMPARE(pixel2, color);
 }
 
 void tst_QPainter::drawPath_data()
@@ -2619,28 +2689,6 @@ void tst_QPainter::porterDuff_warning()
     QVERIFY(qInstallMessageHandler(old) == porterDuff_warningChecker);
 }
 
-class quint24
-{
-public:
-    inline quint24(quint32 v)
-    {
-        data[0] = qBlue(v);
-        data[1] = qGreen(v);
-        data[2] = qRed(v);
-    }
-
-    inline operator quint32 ()
-    {
-        return qRgb(data[2], data[1], data[0]);
-    }
-
-    inline bool operator==(const quint24 &v) const {
-        return (data[0] == v.data[0] && data[1] == v.data[1] && data[2] == v.data[2]);
-    }
-
-    uchar data[3];
-};
-
 void tst_QPainter::drawhelper_blend_color()
 {
     QImage dest(32, 32, QImage::Format_ARGB8555_Premultiplied);
@@ -4064,10 +4112,10 @@ void tst_QPainter::extendedBlendModes()
 
     QVERIFY(testCompositionMode(255, 255, 255, QPainter::CompositionMode_Plus, 0.3));
     QVERIFY(testCompositionMode(  0,   0,   0, QPainter::CompositionMode_Plus, 0.3));
-    QVERIFY(testCompositionMode(127, 128, 165, QPainter::CompositionMode_Plus, 0.3));
-    QVERIFY(testCompositionMode(127,   0,  37, QPainter::CompositionMode_Plus, 0.3));
+    QVERIFY(testCompositionMode(126, 128, 165, QPainter::CompositionMode_Plus, 0.3));
+    QVERIFY(testCompositionMode(127,   0,  38, QPainter::CompositionMode_Plus, 0.3));
     QVERIFY(testCompositionMode(  0, 127, 127, QPainter::CompositionMode_Plus, 0.3));
-    QVERIFY(testCompositionMode(255,   0,  75, QPainter::CompositionMode_Plus, 0.3));
+    QVERIFY(testCompositionMode(255,   0,  76, QPainter::CompositionMode_Plus, 0.3));
     QVERIFY(testCompositionMode(  0, 255, 255, QPainter::CompositionMode_Plus, 0.3));
     QVERIFY(testCompositionMode(128, 128, 166, QPainter::CompositionMode_Plus, 0.3));
     QVERIFY(testCompositionMode(186, 200, 255, QPainter::CompositionMode_Plus, 0.3));