Re: Thoughts about a new GdkPixbuf transform interface
- From: Oleg Klimov <quif land ru>
- To: Bill Haneman <gtk-devel-list gnome org>
- Subject: Re: Thoughts about a new GdkPixbuf transform interface
- Date: Thu, 20 Feb 2003 17:04:06 +0300
Bill Haneman wrote:
- You have end up with a choice for the pipeline of:
 - Pixel based. Possibly incredibly slow and inefficient
when you have steps that base one destination pixel
on multiple source pixels.
 - Do the whole image at each step of the pipeline.
Easy, fast, but you don't get any memory usage
savings over a simpler interface without filter
 - Tile based. Complex, complex, complex.
Yep. My suggestion would be to choose implementation #2 first, but
build the APIs with #2 in mind, so that enterprising people could patch
M-m-m... I'm working on this stuff because I need it. I know what I
š- arbitrary affine transform, speed
š- clear code
š- drawing (lines etc)
š- clipping region
Now I'm looking at your discussion of #1-2-3 and can't help but think:
who will need it?..
There are two ways of chaining transformations:
1. Write new algorithm that contain two transformations at once
2. Apply first, then second
You can't do 1 in general case. You can do 2, but result is loss of
šquality (example: two
rotations in a row, result is worse then one rotation on
angle1+angle2). Why build the
whole new 'tile' infrastructure to have the result identical (bad) to
just applying two
transformations? 30% memory saving (large images: src+dest+tmpbuffer,
But I rather consider reasonable to derive from Transformation object.
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