Fix tiled blit in 16-bit mode

Optimizations in change 8e447e8a did not handle the case when the target
width is less than the width of a tile.

Task-number: 260759
Reviewed-by: Samuel

1 files changed, 7 insertions, 4 deletions

diff --git a/src/gui/painting/qdrawhelper.cpp b/src/gui/painting/qdrawhelper.cpp
index ab192c5a32..e9b1bd3939 100644
--- a/src/gui/painting/qdrawhelper.cpp
+++ b/src/gui/painting/qdrawhelper.cpp
@@ -4953,15 +4953,18 @@ Q_STATIC_TEMPLATE_FUNCTION void blendTiled(int count, const QSpan *spans, void *
 
         if (modeSource && coverage == 255) {
             // Copy the first texture block
-            length = image_width;
+            length = qMin(image_width,length);
+            int tx = x;
             while (length) {
                 int l = qMin(image_width - sx, length);
                 if (buffer_size < l)
                     l = buffer_size;
-                DST *dest = ((DST*)data->rasterBuffer->scanLine(spans->y)) + x;
+                DST *dest = ((DST*)data->rasterBuffer->scanLine(spans->y)) + tx;
                 const SRC *src = (SRC*)data->texture.scanLine(sy) + sx;
+
                 qt_memconvert<DST, SRC>(dest, src, l);
                 length -= l;
+                tx += l;
                 sx = 0;
             }
 
@@ -4971,8 +4974,8 @@ Q_STATIC_TEMPLATE_FUNCTION void blendTiled(int count, const QSpan *spans, void *
             // We are dealing with one block of data
             // - More likely to fit in the cache
             // - can use memcpy
-            int copy_image_width = image_width;
-            length = spans->len - image_width;
+            int copy_image_width = qMin(image_width, int(spans->len));
+            length = spans->len - copy_image_width;
             DST *src = ((DST*)data->rasterBuffer->scanLine(spans->y)) + x;
             DST *dest = src + copy_image_width;
             while (copy_image_width < length) {