Changes: MScalableImage: Remove cached pixmap from QPixmapCache manually

RevBy: Armin Berres

Details: Currently the scalable image gets cached in QPixmapCache if it is not rendered by an OpenGL-backend. But it does not get removed manually, which leads to an unnecessary increasing of QPixmapCache. Although QPixmapCache internally takes care to release pixmaps that are not used during a specific period of time, not manually releasing results in several MB of additional peak for some usecases.

2 files changed, 14 insertions, 0 deletions

diff --git a/src/corelib/painting/mscalableimage.cpp b/src/corelib/painting/mscalableimage.cpp
index f3d07783..76487a0b 100644
--- a/src/corelib/painting/mscalableimage.cpp
+++ b/src/corelib/painting/mscalableimage.cpp
@@ -35,6 +35,10 @@ MScalableImagePrivate::MScalableImagePrivate()
 
 MScalableImagePrivate::~MScalableImagePrivate()
 {
+    if (!cachedImageKey.isEmpty()) {
+        QPixmapCache::remove(cachedImageKey);
+        cachedImageKey.clear();
+    }
 }
 
 void MScalableImagePrivate::validateSize() const
@@ -133,6 +137,9 @@ void MScalableImagePrivate::drawScalable9(qreal x, qreal y, qreal w, qreal h, QP
             // draw to screen
             painter->drawPixmap(x, y, scaled);
             QPixmapCache::insert(key, scaled);
+
+            // remember the key so that the entry can be removed on-demand
+            const_cast<MScalableImagePrivate*>(this)->cachedImageKey = key;
         } else {
             // caching isn't permitted for this case; scale and render direct to screen.
             #if defined(M_OS_MAEMO5)
@@ -145,6 +152,11 @@ void MScalableImagePrivate::drawScalable9(qreal x, qreal y, qreal w, qreal h, QP
                 drawBorderPixmap(painter, QRectF(x, y, w, h), margins, *m_image);
                 painter->setRenderHint(QPainter::SmoothPixmapTransform, enabled);
             #endif //defined(M_OS_MAEMO5)
+
+            if (!cachedImageKey.isEmpty()) {
+                QPixmapCache::remove(cachedImageKey);
+                const_cast<MScalableImagePrivate*>(this)->cachedImageKey.clear();
+            }
         }
     }
 }
diff --git a/src/corelib/painting/mscalableimage_p.h b/src/corelib/painting/mscalableimage_p.h
index 7229d5da..7c065a26 100644
--- a/src/corelib/painting/mscalableimage_p.h
+++ b/src/corelib/painting/mscalableimage_p.h
@@ -86,6 +86,8 @@ public:
 
     QString pixmapId;
 
+    QString cachedImageKey;
+
 protected:
     MScalableImage *q_ptr;
 };