Let me try to be a bit more specific, one issue at a time. ---------------------------------------------------------------------- I agree that, at least at low order (which is all we're doing for now), abyss policies are independent of whether we are using the "center" or "corner" image conventions, and are also independent of whether we are implementing an exact area method (like most implementations of box filtering), or a point resampler (like standard bicubic). However, Øyvind expressed a desire to have something implemented in or for the resamplers which cannot really be done with the usual abyss policy implementations. Here is: Associate a "default" constant colour with a buffer. What Øyvind would like (if I understand correctly) is that instead of sampling through the implied boundary using the resampler as if there was no boundary (filling in the missing footprint values using the abyss policy), the resampled values "drop dead" at the boundary and from then on are filled (filled, not blended) with the default colour. For example, the sampler could use the nearest neighbour abyss policy (a.k.a. clamp) for requested values up to the boundary line, and return the default colour past it. Comment: Thinking about this some more, I am starting to think that it is a bad idea to implement this. (Later.) Irregardless of whether this is a good or bad idea, the main point is: Where should the "drop dead" transition occur: Aligned with the (center of) the boundary pixels? Or half a pixel width out (at the boundary of the pixel area associated with boundary pixels)? One of my worries is that if one when doing something else than resizing this will essentially behave like nearest neighbour (from the outside in), which will be ugly. So, >>I<< am actually starting to think that "drop dead" is not such a good idea. But I'd love to hear opinions on this. nicolas _______________________________________________ Gegl-developer mailing list Gegl-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
