Is interpolation of image-border specified by Render?

Clemens Eisserer linuxhippy at gmail.com
Sat Oct 18 03:35:23 PDT 2008


Hi Maarten,

> Do you have a test program or at least share the transformation matrix
> you're using, because i'm curious why it fails so badly.
Yes I created one, http://pastebin.com/f729a71aa
The testcase works perfectly with pixman (even with much higher
scale), but on intel seems the mask has too small x/y values.
Would be really interesting how other hardware/drivers behave ;)

>Have you
> tried using a 1x1 mask pixel and scaling that an integer amount?
I used a 16x16 mask ... just without any further thinking, thought it
would give me more headroom till I hit precision limits.
I've now tried it with a 1x1 mask (as in the attached testcase), its the same.
It seems only to work when mask is 0.75-1.5 of the size of the source,
otherwise the pixel-borders differ :-/

Thanks, Clemens



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