QPixmap don't assume QPlatformScreen::format is opaque

QRasterPlatformPixmap::systemOpaqueFormat returned QPlatformScreen::format
without checking that the format was actually opaque.

This caused several QPixmap tests to fail on Wayland because Wayland
compositors don't communicate the native format of the screen, just a list of
supported pixel formats, so we just return ARGB32_premultiplied in
QWaylandScreen::format().

Rename the method systemOpaqueFormat to systemNativeFormat since that's how
it's used most of the time. And do a conversion when we actually care whether
the format is opaque or not.

Task-number: QTBUG-51748
Change-Id: I47dc1c3f185fb802016ca361206d47d02e8d3cf1
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/gui/image/qpixmap_raster.cpp b/src/gui/image/qpixmap_raster.cpp
index 51b4309e0a..431002d032 100644
--- a/src/gui/image/qpixmap_raster.cpp
+++ b/src/gui/image/qpixmap_raster.cpp
@@ -89,7 +89,7 @@ QRasterPlatformPixmap::~QRasterPlatformPixmap()
 {
 }
 
-QImage::Format QRasterPlatformPixmap::systemOpaqueFormat()
+QImage::Format QRasterPlatformPixmap::systemNativeFormat()
 {
     if (!QGuiApplication::primaryScreen())
         return QImage::Format_RGB32;
@@ -107,7 +107,7 @@ void QRasterPlatformPixmap::resize(int width, int height)
     if (pixelType() == BitmapType)
         format = QImage::Format_MonoLSB;
     else
-        format = systemOpaqueFormat();
+        format = systemNativeFormat();
 
     image = QImage(width, height, format);
     w = width;
@@ -314,8 +314,9 @@ void QRasterPlatformPixmap::createPixmapForImage(QImage sourceImage, Qt::ImageCo
                     ? QImage::Format_ARGB32_Premultiplied
                     : QImage::Format_RGB32;
         } else {
-            QImage::Format opaqueFormat = systemOpaqueFormat();
-            QImage::Format alphaFormat = qt_alphaVersionForPainting(opaqueFormat);
+            QImage::Format nativeFormat = systemNativeFormat();
+            QImage::Format opaqueFormat = qt_opaqueVersionForPainting(nativeFormat);
+            QImage::Format alphaFormat = qt_alphaVersionForPainting(nativeFormat);
 
             if (!sourceImage.hasAlphaChannel()) {
                 format = opaqueFormat;