On Sunday 27 November 2005 10:00, Chris Cannam wrote:
> G:
> > Googling didn't reveal anything about such a limitation.
>
> Good thing you have me, then, eh?
>
> Well, maybe we should test it (should be easily done by
> just zooming in, surely?).  But I think Qt just uses an
> X Pixmap for QPixmap, and their dimensions are limited
> to 16 bits worth of pixels.

All the QPixmap's doc says is "Pixel data in a pixmap is internal and is 
managed by the underlying window system". But looking at Qt's code it does 
use an XImage internally, and indeed zooming to 2000% with a long enough 
audio segment produces garbage (the rect's width is 35999, so I guess that 
it's *signed* 16 bits worth of pixels).

But QImages don't really solve the problem because drawing them on a widget 
means converting them to QPixmaps, and this conversion is described as being 
slow in Qt's docs.

*sigh*.

-- 
Guillaume.
http://www.telegraph-road.org


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