Automatically destroy VG pixmaps when the last window surface goes away

Under S60, Qt will destroy the window surfaces of an application that
goes into the background, which frees up EGL surface objects.  But the
VGImage's for pixmaps, and the EGLContext, were still using GPU memory.

This change keeps track of the number of widgets / window surfaces that
are in use and then calls hibernate() on all QVGPixmapData objects when
it goes to zero.  Once all the VGImage's are destroyed, the EGLContext
should also be destroyed.

Task-number: QT-2555
Reviewed-by: Sarah Smith

1 files changed, 29 insertions, 4 deletions

diff --git a/src/openvg/qpixmapdata_vg.cpp b/src/openvg/qpixmapdata_vg.cpp
index 19c90ed..5d5fcbf 100644
--- a/src/openvg/qpixmapdata_vg.cpp
+++ b/src/openvg/qpixmapdata_vg.cpp
@@ -65,12 +65,21 @@ QVGPixmapData::QVGPixmapData(PixelType type)
     recreate = true;
 #if !defined(QT_NO_EGL)
     context = 0;
+    qt_vg_register_pixmap(this);
 #endif
     setSerialNumber(++qt_vg_pixmap_serial);
 }
 
 QVGPixmapData::~QVGPixmapData()
 {
+    destroyImageAndContext();
+#if !defined(QT_NO_EGL)
+    qt_vg_unregister_pixmap(this);
+#endif
+}
+
+void QVGPixmapData::destroyImageAndContext()
+{
     if (vgImage != VG_INVALID_HANDLE) {
         // We need to have a context current to destroy the image.
 #if !defined(QT_NO_EGL)
@@ -93,11 +102,16 @@ QVGPixmapData::~QVGPixmapData()
         if (vgImageOpacity != VG_INVALID_HANDLE)
             vgDestroyImage(vgImageOpacity);
 #endif
+        vgImage = VG_INVALID_HANDLE;
+        vgImageOpacity = VG_INVALID_HANDLE;
     }
 #if !defined(QT_NO_EGL)
-    if (context)
-        qt_vg_destroy_context(context);
+    if (context) {
+        qt_vg_destroy_context(context, QInternal::Pixmap);
+        context = 0;
+    }
 #endif
+    recreate = true;
 }
 
 QPixmapData *QVGPixmapData::createCompatiblePixmapData() const
@@ -217,7 +231,7 @@ VGImage QVGPixmapData::toVGImage()
 #if !defined(QT_NO_EGL)
     // Increase the reference count on the shared context.
     if (!context)
-        context = qt_vg_create_context(0);
+        context = qt_vg_create_context(0, QInternal::Pixmap);
 #endif
 
     if (recreate && prevSize != QSize(w, h)) {
@@ -286,6 +300,17 @@ VGImage QVGPixmapData::toVGImage(qreal opacity)
 #endif
 }
 
+void QVGPixmapData::hibernate()
+{
+    // If the image was imported (e.g, from an SgImage under Symbian),
+    // then we cannot copy it back to main memory for storage.
+    if (vgImage != VG_INVALID_HANDLE && source.isNull())
+        return;
+
+    forceToImage();
+    destroyImageAndContext();
+}
+
 extern int qt_defaultDpiX();
 extern int qt_defaultDpiY();
 
@@ -376,7 +401,7 @@ void QVGPixmapData::fromNativeType(void* pixmap, NativeType type)
         // when "0" used as argument then
         // default display, context are used
         if (!context)
-            context = qt_vg_create_context(0);
+            context = qt_vg_create_context(0, QInternal::Pixmap);
 
         if (vgImage != VG_INVALID_HANDLE) {
             vgDestroyImage(vgImage);