[Qt-interest] Painting on QImage vs. QPixmap

[Brad Howes]

On Mar 24, 2009, at 1:04 PM, Jesús Fernández wrote:

> From http://doc.trolltech.com/4.5/qpixmap.html:
>
> Qt provides four classes for handling image data: QImage, QPixmap,  
> QBitmap and QPicture. QImage is designed and optimized for I/O, and  
> for direct pixel access and manipulation, while QPixmap is designed  
> and optimized for showing images on screen. QBitmap is only a  
> convenience class that inherits QPixmap, ensuring a depth of 1. The  
> isQBitmap() function returns true if a QPixmap object is really a  
> bitmap, otherwise returns false. Finally, the QPicture class is a  
> paint device that records and replays QPainter commands.
>
> Thanks anyway ;)

For what? I knew that blurb but was curious as to the actual  
circumstances when one would be faster than the other. The blurb does  
not indicate that drawing into a QPixmap would be faster than QImage,  
and yet that can be true.

Brad

-- 
Brad Howes
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