Fix big-endian build

Declare rbSwap<QImage::Format_RGBA8888>, so we don't end up in a
fallback definition not used by little-endian.

Task-number: QTBUG-69951
Change-Id: I8512bba76da7d59a27593d37c70283d881c3e8fc
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/gui/painting/qdrawhelper.cpp b/src/gui/painting/qdrawhelper.cpp
index b1424b5b0a..4b68c22e95 100644
--- a/src/gui/painting/qdrawhelper.cpp
+++ b/src/gui/painting/qdrawhelper.cpp
@@ -640,6 +640,19 @@ void QT_FASTCALL rbSwap<QImage::Format_RGBA8888>(uchar *d, const uchar *s, int c
 {
     return rbSwap_rgb32(d, s, count);
 }
+#else
+template<>
+void QT_FASTCALL rbSwap<QImage::Format_RGBA8888>(uchar *d, const uchar *s, int count)
+{
+    const uint *src = reinterpret_cast<const uint *>(s);
+    uint *dest = reinterpret_cast<uint *>(d);
+    for (int i = 0; i < count; ++i) {
+        const uint c = src[i];
+        const uint rb = c & 0xff00ff00;
+        const uint ga = c & 0x00ff00ff;
+        dest[i] = ga | (rb << 16) | (rb >> 16);
+    }
+}
 #endif
 
 static void QT_FASTCALL rbSwap_rgb30(uchar *d, const uchar *s, int count)