Fixed slow QPixmap::fill() when the pixmap is sharing data.

If the pixmap is sharing data with other pixmaps, it must be detached
before it is filled. Instead of detaching by making a copy, create a
new uninitialized data object since all pixels are overwritten by
fill() anyway.

Task-number: QTBUG-3228
Reviewed-by: Trond

1 files changed, 11 insertions, 1 deletions

diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index c03a364..bf6c9ae 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -959,7 +959,17 @@ void QPixmap::fill(const QColor &color)
         return;
     }
 
-    detach();
+    if (data->ref == 1) {
+        // detach() will also remove this pixmap from caches, so
+        // it has to be called even when ref == 1.
+        detach();
+    } else {
+        // Don't bother to make a copy of the data object, since
+        // it will be filled with new pixel data anyway.
+        QPixmapData *d = data->createCompatiblePixmapData();
+        d->resize(data->width(), data->height());
+        data = d;
+    }
     data->fill(color);
 }