From 0ff1dc7110d373c85ce41e90073291b5e2eb16ad Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Thu, 11 Feb 2021 11:23:05 +0100
Subject: Fix alpha handling of QImage::setPixel

It was treated differently depending on format, made it consistently
behave the same for all formats (following the behavior of the primary
formats).

Change-Id: Ie24e19957d076fdf3ebd333074e26ede187489eb
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit c32cd44d34910cfd42e32537578e4a573138a282)
---
 src/gui/image/qimage.cpp          | 11 +++++++++--
 src/gui/painting/qpixellayout.cpp | 22 +++++++++++++++++-----
 2 files changed, 26 insertions(+), 7 deletions(-)

(limited to 'src/gui')

diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 2c356dba16..9a9ab873ff 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -2470,7 +2470,7 @@ void QImage::setPixel(int x, int y, uint index_or_rgb)
         ((uint *)s)[x] = index_or_rgb;
         return;
     case Format_RGB16:
-        ((quint16 *)s)[x] = qConvertRgb32To16(qUnpremultiply(index_or_rgb));
+        ((quint16 *)s)[x] = qConvertRgb32To16(index_or_rgb);
         return;
     case Format_RGBX8888:
         ((uint *)s)[x] = ARGB2RGBA(0xff000000 | index_or_rgb);
@@ -2491,6 +2491,10 @@ void QImage::setPixel(int x, int y, uint index_or_rgb)
     case Format_A2RGB30_Premultiplied:
         ((uint *)s)[x] = qConvertArgb32ToA2rgb30<PixelOrderRGB>(index_or_rgb);
         return;
+    case Format_RGBA64:
+    case Format_RGBA64_Premultiplied:
+        ((QRgba64 *)s)[x] = QRgba64::fromArgb32(index_or_rgb);
+        return;
     case Format_Invalid:
     case NImageFormats:
         Q_ASSERT(false);
@@ -2500,7 +2504,10 @@ void QImage::setPixel(int x, int y, uint index_or_rgb)
     }
 
     const QPixelLayout *layout = &qPixelLayouts[d->format];
-    layout->storeFromARGB32PM(s, &index_or_rgb, x, 1, nullptr, nullptr);
+    if (!hasAlphaChannel())
+        layout->storeFromRGB32(s, &index_or_rgb, x, 1, nullptr, nullptr);
+    else
+        layout->storeFromARGB32PM(s, &index_or_rgb, x, 1, nullptr, nullptr);
 }
 
 /*!
diff --git a/src/gui/painting/qpixellayout.cpp b/src/gui/painting/qpixellayout.cpp
index 3b05e98318..c0b0b1c2e8 100644
--- a/src/gui/painting/qpixellayout.cpp
+++ b/src/gui/painting/qpixellayout.cpp
@@ -1303,7 +1303,7 @@ static void QT_FASTCALL storeRGB64FromRGB32(uchar *dest, const uint *src, int in
 {
     QRgba64 *d = reinterpret_cast<QRgba64 *>(dest) + index;
     for (int i = 0; i < count; ++i)
-        d[i] = QRgba64::fromArgb32(src[i]);
+        d[i] = QRgba64::fromArgb32(src[i] | 0xff000000);
 }
 
 static const uint *QT_FASTCALL fetchRGBA64ToARGB32PM(uint *buffer, const uchar *src, int index, int count,
@@ -1315,12 +1315,24 @@ static const uint *QT_FASTCALL fetchRGBA64ToARGB32PM(uint *buffer, const uchar *
     return buffer;
 }
 
+template<bool Mask>
 static void QT_FASTCALL storeRGBA64FromARGB32PM(uchar *dest, const uint *src, int index, int count,
                                                 const QList<QRgb> *, QDitherInfo *)
 {
     QRgba64 *d = reinterpret_cast<QRgba64 *>(dest) + index;
-    for (int i = 0; i < count; ++i)
+    for (int i = 0; i < count; ++i) {
         d[i] = QRgba64::fromArgb32(src[i]).unpremultiplied();
+        if (Mask)
+            d[i].setAlpha(65535);
+    }
+}
+
+static void QT_FASTCALL storeRGBA64FromARGB32(uchar *dest, const uint *src, int index, int count,
+                                              const QList<QRgb> *, QDitherInfo *)
+{
+    QRgba64 *d = reinterpret_cast<QRgba64 *>(dest) + index;
+    for (int i = 0; i < count; ++i)
+        d[i] = QRgba64::fromArgb32(src[i]);
 }
 
 // Note:
@@ -1407,15 +1419,15 @@ QPixelLayout qPixelLayouts[QImage::NImageFormats] = {
     { false, false, QPixelLayout::BPP64, nullptr,
       convertPassThrough, nullptr,
       fetchRGB64ToRGB32, fetchPassThrough64,
-      storeRGB64FromRGB32, storeRGB64FromRGB32 }, // Format_RGBX64
+      storeRGBA64FromARGB32PM<true>, storeRGB64FromRGB32 }, // Format_RGBX64
     { true, false, QPixelLayout::BPP64, nullptr,
       convertARGB32ToARGB32PM, nullptr,
       fetchRGBA64ToARGB32PM, fetchRGBA64ToRGBA64PM,
-      storeRGBA64FromARGB32PM, storeRGB64FromRGB32 }, // Format_RGBA64
+      storeRGBA64FromARGB32PM<false>, storeRGB64FromRGB32 }, // Format_RGBA64
     { true, true, QPixelLayout::BPP64, nullptr,
       convertPassThrough, nullptr,
       fetchRGB64ToRGB32, fetchPassThrough64,
-      storeRGB64FromRGB32, storeRGB64FromRGB32 }, // Format_RGBA64_Premultiplied
+      storeRGBA64FromARGB32, storeRGB64FromRGB32 }, // Format_RGBA64_Premultiplied
     { false, false, QPixelLayout::BPP16, nullptr,
       convertGrayscale16ToRGB32, convertGrayscale16ToRGBA64,
       fetchGrayscale16ToRGB32, fetchGrayscale16ToRGBA64,
-- 
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