[Digikam-devel] [Kde-imaging] Exposure Blending tool finalization...

[Marcel Wiesweg]

> But it's the same for Digikam::Dimg excepted that caching pixmap is
> 
> - more ingenious. We compute caching pixmap from DImg only when we
> need to paint scrollview content.
> - We use tiled pixmap, as Gimp and photoshop do.
> - faster because we only show what we need to see on scrollview.
> - We use a large part of memory to store cache data (70Mb if remember)
> - scaling code from imlib2 is really great there.

And we dont have the network roundtrip to the X server and no possibly lossy 
color space conversions.

> 
> I suspect that QGraphicView show pixmap inside a QLabel and resize
> whole content on the fly (whole Pixmap). This is definitively a bad
> way.

It may be clever and resize only the needed part, but any scaling of a QPixmap 
is bad (tm).

> 
> Sure it work fast with small image, which is usefull to display with
> drawing items (not pixmap) but not really to display a large picture.

Exactly