Do not always use argb32pm for subsurfaces

A number of drawing paths were never tested by lancelot because we
always used argb32pm for subsurfaces. This patch switches the
subsurfaces to use the painter format or its alpha version. This means
changes to composition tests as it changes precision, especially of
alpha in the a2rgb30 formats.

Change-Id: I24d53bf6e1db8cca36bda69e2ddf07f20256b3c8
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

1 files changed, 8 insertions, 1 deletions

diff --git a/tests/auto/other/lancelot/paintcommands.cpp b/tests/auto/other/lancelot/paintcommands.cpp
index c28812e120..8419f93e3b 100644
--- a/tests/auto/other/lancelot/paintcommands.cpp
+++ b/tests/auto/other/lancelot/paintcommands.cpp
@@ -36,6 +36,7 @@
 #include <qtextlayout.h>
 #include <qdebug.h>
 #include <QStaticText>
+#include <private/qimage_p.h>
 
 #ifndef QT_NO_OPENGL
 #include <QOpenGLFramebufferObjectFormat>
@@ -2402,7 +2403,13 @@ void PaintCommands::command_surface_begin(QRegExp re)
         m_painter = new QPainter(&m_surface_pixmap);
 #endif
     } else {
-        m_surface_image = QImage(qRound(w), qRound(h), QImage::Format_ARGB32_Premultiplied);
+        QImage::Format surface_format;
+        if (QImage::toPixelFormat(m_format).alphaUsage() != QPixelFormat::UsesAlpha)
+            surface_format = qt_alphaVersion(m_format);
+        else
+            surface_format = m_format;
+
+        m_surface_image = QImage(qRound(w), qRound(h), surface_format);
         m_surface_image.fill(0);
         m_painter = new QPainter(&m_surface_image);
     }