On Sat, Oct 18, 2008 at 12:58 AM, Clemens Eisserer <[EMAIL PROTECTED]> wrote: > Hi, > > I am compositing a transformed source with RepeatPad (and billinear > interpolation) and a mask (nearest) to get sharp edges. > What I do for now is I draw a rect in the mask as large as the source > and apply the same transformation. > > However this requires me to have a mask as large or larger as the > source and fillrects touching a large area. > I've experimented with having a smaller mask and appling an additional > scale to the mask and it seems to work fine when using nearest > interpolation. > It seems the mask-border is exactly as if the image would be as large > as the source, and only the content of the mask is interpolated with > nearest, the upper image shows the result (with a 2x2 mask scaled up): > http://picasaweb.google.com/linuxhippy/Transformations#5229203425413416738 > > However I am worried how consistent this is across different drivers, > can I rely on this behaviour if I handle rouding errors caused by the > fixed-point transformation matrix? > Is it specified which pixels may be touched? > How hard is it for drivers to have a mask with nearest and a source > with billinear? > > Thank you in advance, Clemens > _______________________________________________ > xorg mailing list > xorg@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/xorg >
Bilinear and nearest are standard texture unit properties, this should pose no difficulty for drivers. As far as the mask goes, nearest should guarantee a sharp border. I'd expect things to go ok with the size if you keep in mind it's fixed point transformation, but i'm not a 100% sure. Maarten. _______________________________________________ xorg mailing list xorg@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/xorg
