Implement support for 16bpc image formats

Adds support for 16bit per color image formats in QImage. This makes it
possible to read and write 16bpc PNGs, and take full advantage of the
16bpc paint engine.

[ChangeLog][QtGui][QImage] QImage now supports 64bit image formats with
16 bits per color channel, compatible with 16bpc PNG or RGBA16 OpenGL
formats.

Task-number: QTBUG-45858
Change-Id: Icd28bd5868a6efcf65cb5bd56031d42941e04099
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 34 insertions, 13 deletions

diff --git a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
index 58ac025f0c..877306e8b8 100644
--- a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
+++ b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp
@@ -1091,6 +1091,7 @@ void tst_QPainter::fillRect_data()
 
     QTest::newRow("argb32pm") << QImage::Format_ARGB32_Premultiplied;
     QTest::newRow("rgba8888pm") << QImage::Format_RGBA8888_Premultiplied;
+    QTest::newRow("rgba64pm") << QImage::Format_RGBA64_Premultiplied;
 }
 
 void tst_QPainter::fillRect()
@@ -2443,6 +2444,24 @@ void tst_QPainter::setOpacity_data()
     QTest::newRow("A2RGB30P on RGB30") << QImage::Format_RGB30
                                        << QImage::Format_A2RGB30_Premultiplied;
 
+    QTest::newRow("RGBA64P on RGBA64P") << QImage::Format_RGBA64_Premultiplied
+                                        << QImage::Format_RGBA64_Premultiplied;
+
+    QTest::newRow("RGBA64 on RGBA64") << QImage::Format_RGBA64
+                                      << QImage::Format_RGBA64;
+
+    QTest::newRow("RGBx64 on RGBx64") << QImage::Format_RGBX64
+                                      << QImage::Format_RGBX64;
+
+    QTest::newRow("RGBA64P on ARGB32P") << QImage::Format_ARGB32_Premultiplied
+                                        << QImage::Format_RGBA64_Premultiplied;
+
+    QTest::newRow("RGBx64 on ARGB32P") << QImage::Format_ARGB32_Premultiplied
+                                       << QImage::Format_RGBX64;
+
+    QTest::newRow("ARGB32P on RGBA64P") << QImage::Format_RGBA64_Premultiplied
+                                        << QImage::Format_ARGB32_Premultiplied;
+
 }
 
 void tst_QPainter::setOpacity()
@@ -3847,6 +3866,8 @@ void tst_QPainter::gradientPixelFormat_data()
     QTest::newRow("rgbx8888") << QImage::Format_RGBX8888;
     QTest::newRow("rgba8888") << QImage::Format_RGBA8888;
     QTest::newRow("rgba8888_pm") << QImage::Format_RGBA8888_Premultiplied;
+    QTest::newRow("rgbx64") << QImage::Format_RGBX64;
+    QTest::newRow("rgba64_pm") << QImage::Format_RGBA64_Premultiplied;
 }
 
 void tst_QPainter::gradientPixelFormat()
@@ -4784,7 +4805,19 @@ void tst_QPainter::blendARGBonRGB_data()
                                            << QPainter::CompositionMode_SourceIn << qRgba(255, 0, 0, 127) << 255 ;
     QTest::newRow("ARGB_PM source-in ARGB32") << QImage::Format_ARGB32 << QImage::Format_ARGB32_Premultiplied
                                               << QPainter::CompositionMode_SourceIn << qRgba(127, 0, 0, 127) << 255;
-    // Only ARGB does inverse premultiply, on the rest over and source gives similar results:
+    QTest::newRow("ARGB over RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
+                                        << QPainter::CompositionMode_SourceOver << qRgba(255, 0, 0, 127) << 127;
+    QTest::newRow("ARGB_PM over RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
+                                           << QPainter::CompositionMode_SourceOver << qRgba(127, 0, 0, 127) << 127;
+    QTest::newRow("ARGB source RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
+                                          << QPainter::CompositionMode_Source << qRgba(255, 0, 0, 127) << 255;
+    QTest::newRow("ARGB_PM source RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
+                                             << QPainter::CompositionMode_Source << qRgba(127, 0, 0, 127) << 255;
+    QTest::newRow("ARGB source-in RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
+                                             << QPainter::CompositionMode_SourceIn << qRgba(255, 0, 0, 127) << 255;
+    QTest::newRow("ARGB_PM source-in RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
+                                                << QPainter::CompositionMode_SourceIn << qRgba(127, 0, 0, 127) << 255;
+    // Only ARGB32 and RGBA8888 does inverse premultiply, on the rest over and source gives similar results:
     QTest::newRow("ARGB over RGB32") << QImage::Format_RGB32 << QImage::Format_ARGB32
                                      << QPainter::CompositionMode_SourceOver << qRgba(255, 0, 0, 127) << 127;
     QTest::newRow("ARGB_PM over RGB32") << QImage::Format_RGB32 << QImage::Format_ARGB32_Premultiplied
@@ -4821,18 +4854,6 @@ void tst_QPainter::blendARGBonRGB_data()
                                              << QPainter::CompositionMode_SourceIn << qRgba(255, 0, 0, 127) << 127;
     QTest::newRow("ARGB_PM source-in RGBx8888") << QImage::Format_RGBX8888 << QImage::Format_ARGB32_Premultiplied
                                                 << QPainter::CompositionMode_SourceIn << qRgba(127, 0, 0, 127) << 127;
-    QTest::newRow("ARGB over RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
-                                        << QPainter::CompositionMode_SourceOver << qRgba(255, 0, 0, 127) << 127;
-    QTest::newRow("ARGB_PM over RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
-                                           << QPainter::CompositionMode_SourceOver << qRgba(127, 0, 0, 127) << 127;
-    QTest::newRow("ARGB source RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
-                                          << QPainter::CompositionMode_Source << qRgba(255, 0, 0, 127) << 255;
-    QTest::newRow("ARGB_PM source RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
-                                             << QPainter::CompositionMode_Source << qRgba(127, 0, 0, 127) << 255;
-    QTest::newRow("ARGB source-in RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32
-                                             << QPainter::CompositionMode_SourceIn << qRgba(255, 0, 0, 127) << 255;
-    QTest::newRow("ARGB_PM source-in RGBA8888") << QImage::Format_RGBA8888 << QImage::Format_ARGB32_Premultiplied
-                                                << QPainter::CompositionMode_SourceIn << qRgba(127, 0, 0, 127) << 255;
     QTest::newRow("ARGB over RGB16") << QImage::Format_RGB16 << QImage::Format_ARGB32
                                      << QPainter::CompositionMode_SourceOver << qRgba(255, 0, 0, 127) << 123;
     QTest::newRow("ARGB_PM over RGB16") << QImage::Format_RGB16 << QImage::Format_ARGB32_Premultiplied