tst_QStyle::drawItemPixmap(): Check on the image color

Verify that all pixels of the grabbed image are green instead
of comparing an image loaded from file.
The test then also passes when High DPI scaling is active in
which case a twice as big pixmap with DPR=2 is obtained when
grabbing the widget.

Change-Id: Ie5244a39a68ea0defd2590cf30f251d660d0869b
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 8 insertions, 7 deletions

diff --git a/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp b/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
index 5925b764dd..fcb05f6b74 100644
--- a/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
+++ b/tests/auto/widgets/styles/qstyle/tst_qstyle.cpp
@@ -58,6 +58,8 @@
 #include <qscrollarea.h>
 #include <qwidget.h>
 
+#include <algorithm>
+
 // Make a widget frameless to prevent size constraints of title bars
 // from interfering (Windows).
 static inline void setFrameless(QWidget *w)
@@ -208,13 +210,12 @@ void tst_QStyle::drawItemPixmap()
     testWidget->resize(300, 300);
     testWidget->showNormal();
 
-    const QString imageFileName = QFINDTESTDATA("task_25863.png");
-    QVERIFY(!imageFileName.isEmpty());
-
-    QPixmap p(imageFileName, "PNG");
-    const QPixmap actualPix = testWidget->grab();
-
-    QCOMPARE(actualPix, p);
+    QImage image = testWidget->grab().toImage();
+    const QRgb green = QColor(Qt::green).rgb();
+    QVERIFY(image.reinterpretAsFormat(QImage::Format_RGB32));
+    const QRgb *bits = reinterpret_cast<const QRgb *>(image.constBits());
+    const QRgb *end = bits + image.byteCount() / sizeof(QRgb);
+    QVERIFY(std::all_of(bits, end, [green] (QRgb r) { return r == green; }));
     testWidget->hide();
 }