Speed up QPixmap::width(), height(), isNull() and depth().

This change moves the w, h, d variables to QPixmapData and introduces
is_null to keep track of nullness. This is possible only because
QPixmapData is internal API; otherwise we'd have to be smarter.

The optimization makes the QPixmap::width() function take 7 instructions,
down from 34 before. For the calculator demo in the declarative ui branch
this reduces a block of 750000 instructions (out of 30000000) to around
100000-150000 instructions.

Tested on Windows, Linux, Mac. Raster, X11 and OpenGL paint engines. Have
not tested the DirectFB engine.

Reviewed-by: Trond

1 files changed, 8 insertions, 0 deletions

diff --git a/src/plugins/gfxdrivers/directfb/qdirectfbpixmap.cpp b/src/plugins/gfxdrivers/directfb/qdirectfbpixmap.cpp
index c2048d8a3..c23924884 100644
--- a/src/plugins/gfxdrivers/directfb/qdirectfbpixmap.cpp
+++ b/src/plugins/gfxdrivers/directfb/qdirectfbpixmap.cpp
@@ -82,6 +82,10 @@ void QDirectFBPixmapData::resize(int width, int height)
         return;
     }
 
+    w = width;
+    h = height;
+    is_null = (w <= 0 || h <= 0);
+    d = metric(QPaintDevice::PdmDepth);
     setSerialNumber(++global_ser_no);
 }
 
@@ -191,6 +195,10 @@ void QDirectFBPixmapData::fromImage(const QImage &i,
         invalidate();
         return;
     }
+    w = metric(QPaintDevice::PdmWidth);
+    h = metric(QPaintDevice::PdmHeight);
+    is_null = (w <= 0 || h <= 0);
+    d = metric(QPaintDevice::PdmDepth);
     setSerialNumber(++global_ser_no);
 }