Fix premul conversion from ARGB32 to A2RGB30 formats.

When a premultiplied alpha changes value because it is rounded to fewer
bits the premultiplied colors may need to be recalculated with the new
value. Otherwise the color will both be wrong and potentially invalid.

Change-Id: I9ec74a22aac73cd7ffab04e180cf2bf35bb4c315
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/src/gui/painting/qdrawhelper_sse4.cpp b/src/gui/painting/qdrawhelper_sse4.cpp
index 43a3958997..7cc498eefc 100644
--- a/src/gui/painting/qdrawhelper_sse4.cpp
+++ b/src/gui/painting/qdrawhelper_sse4.cpp
@@ -74,6 +74,22 @@ const uint *QT_FASTCALL convertRGBXFromARGB32PM_sse4(uint *buffer, const uint *s
     return buffer;
 }
 
+template<QtPixelOrder PixelOrder>
+const uint *QT_FASTCALL convertA2RGB30PMFromARGB32PM_sse4(uint *buffer, const uint *src, int count,
+                                                          const QPixelLayout *, const QRgb *)
+{
+    for (int i = 0; i < count; ++i)
+        buffer[i] = qConvertArgb32ToA2rgb30_sse4<PixelOrder>(src[i]);
+    return buffer;
+}
+
+template
+const uint *QT_FASTCALL convertA2RGB30PMFromARGB32PM_sse4<PixelOrderBGR>(uint *buffer, const uint *src, int count,
+                                                                         const QPixelLayout *, const QRgb *);
+template
+const uint *QT_FASTCALL convertA2RGB30PMFromARGB32PM_sse4<PixelOrderRGB>(uint *buffer, const uint *src, int count,
+                                                                         const QPixelLayout *, const QRgb *);
+
 QT_END_NAMESPACE
 
 #endif