Re: [PATCH 0/6 v0] RFC: Projective transformation
Chris Wilson <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <[email protected]> |
On Fri, Nov 28, 2014 at 08:31:18PM -0800, Bryce Harrington wrote: > This resurrects a patch proposed some years back for adding 2d > projective transformation support to Cairo. I've reviewed and updated > the patch for the current codebase, and made a test demo to try it out. > There's a bug that occurs on rotational transformations that I haven't > figured out -- suggestions appreciated. > > You might recall that this time last year there was a discussion here > about 4x4 matrices in Cairo for doing more advanced 3d transformations. > There were doubts expressed about whether that would stretch Cairo's > focus too far. However, 2d projective transformation requires only 2 > elements to added to Cairo's matrix support so perhaps is more > in-scope. It's pretty simple, we can not change cairo_matrix_t without breaking ABI. Any perspective matrix must be a new type with new entry points. It also looks like you haven't thought about stroking under a perspective transform, which is the tricky part. The easiest way to first sketch it out is to do a stroke onto the orthogonal plane and then do the perspective transformation. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo