1 files changed, 26 insertions, 11 deletions

diff --git a/src/gui/painting/qdrawhelper.cpp b/src/gui/painting/qdrawhelper.cpp
index ac15d8f4f4..006befea22 100644
--- a/src/gui/painting/qdrawhelper.cpp
+++ b/src/gui/painting/qdrawhelper.cpp
@@ -4566,7 +4566,9 @@ static void blend_color_rgb16(int count, const QSpan *spans, void *userData)
     if (mode == QPainter::CompositionMode_Source) {
         // inline for performance
         ushort c = data->solidColor.toRgb16();
-        while (count--) {
+        for (; count--; spans++) {
+            if (!spans->len)
+                continue;
             ushort *target = ((ushort *)data->rasterBuffer->scanLine(spans->y)) + spans->x;
             if (spans->coverage == 255) {
                 qt_memfill(target, c, spans->len);
@@ -4579,13 +4581,14 @@ static void blend_color_rgb16(int count, const QSpan *spans, void *userData)
                     ++target;
                 }
             }
-            ++spans;
         }
         return;
     }
 
     if (mode == QPainter::CompositionMode_SourceOver) {
-        while (count--) {
+        for (; count--; spans++) {
+            if (!spans->len)
+                continue;
             uint color = BYTE_MUL(data->solidColor.toArgb32(), spans->coverage);
             int ialpha = qAlpha(~color);
             ushort c = qConvertRgb32To16(color);
@@ -4617,7 +4620,6 @@ static void blend_color_rgb16(int count, const QSpan *spans, void *userData)
                 // one last pixel beyond a full word
                 *target = c + BYTE_MUL_RGB16(*target, ialpha);
             }
-            ++spans;
         }
         return;
     }
@@ -4634,6 +4636,11 @@ void handleSpans(int count, const QSpan *spans, const QSpanData *data, T &handle
 
     int coverage = 0;
     while (count) {
+        if (!spans->len) {
+            ++spans;
+            --count;
+            continue;
+        }
         int x = spans->x;
         const int y = spans->y;
         int right = x + spans->len;
@@ -4790,7 +4797,9 @@ static void blend_untransformed_generic(int count, const QSpan *spans, void *use
     int xoff = -qRound(-data->dx);
     int yoff = -qRound(-data->dy);
 
-    while (count--) {
+    for (; count--; spans++) {
+        if (!spans->len)
+            continue;
         int x = spans->x;
         int length = spans->len;
         int sx = xoff + x;
@@ -4818,7 +4827,6 @@ static void blend_untransformed_generic(int count, const QSpan *spans, void *use
                 }
             }
         }
-        ++spans;
     }
 }
 
@@ -4840,7 +4848,9 @@ static void blend_untransformed_generic_rgb64(int count, const QSpan *spans, voi
     int xoff = -qRound(-data->dx);
     int yoff = -qRound(-data->dy);
 
-    while (count--) {
+    for (; count--; spans++) {
+        if (!spans->len)
+            continue;
         int x = spans->x;
         int length = spans->len;
         int sx = xoff + x;
@@ -4868,7 +4878,6 @@ static void blend_untransformed_generic_rgb64(int count, const QSpan *spans, voi
                 }
             }
         }
-        ++spans;
     }
 }
 #endif
@@ -4889,7 +4898,9 @@ static void blend_untransformed_argb(int count, const QSpan *spans, void *userDa
     int xoff = -qRound(-data->dx);
     int yoff = -qRound(-data->dy);
 
-    while (count--) {
+    for (; count--; spans++) {
+        if (!spans->len)
+            continue;
         int x = spans->x;
         int length = spans->len;
         int sx = xoff + x;
@@ -4909,7 +4920,6 @@ static void blend_untransformed_argb(int count, const QSpan *spans, void *userDa
                 op.func(dest, src, length, coverage);
             }
         }
-        ++spans;
     }
 }
 
@@ -4982,7 +4992,12 @@ static void blend_untransformed_rgb565(int count, const QSpan *spans, void *user
     int xoff = -qRound(-data->dx);
     int yoff = -qRound(-data->dy);
 
-    while (count--) {
+    const QSpan *end = spans + count;
+    while (spans < end) {
+        if (!spans->len) {
+            ++spans;
+            continue;
+        }
         const quint8 coverage = (data->texture.const_alpha * spans->coverage) >> 8;
         if (coverage == 0) {
             ++spans;