<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> </head> <body text="#000000" bgcolor="#ffffff"> Dear all, I'm trying to solve clipping bug in current master branch of cairo. As I mentioned before from here <a href="http://lists.freedesktop.org/archives/cairo/2011-June/022046.html">http://lists.freedesktop.org/archives/cairo/2011-June/022046.html,</a> there're some mismatches on making decision to use clip surface or not. Current implementation of _cairo_image_surface_fill() is consist of following stages. 1. Calculate clip boxes. 2. Set clip boxes as limit boxes. 3. Convert given path to desired geometry. 4. _clip_and_composite() resulting geometry. (boxes or polygon) Our final geometry which will be given to _clip_and_composite() may or may not be clipped. If clip can be reduced to a set of boxes, we can assume that our geometry is properly clipped. If not, only extent will be bounded and we should use clip mask surface. Current _clip_and_composite() determines this by extracting region from a clip, i.e. _cairo_clip_get_region() succeed or not. So, if clip cannot be reduced to a set of boxes, _cairo_clip_get_region() should also fail. But unfortunately we cannot assume that. _cairo_clip_to_boxes() internally try to get clip boxes using _cairo_clip_get_boxes(). If it fails, it just returns clip extent. And _cairo_clip_get_boxes() will fail if there're any non-rectilinear paths in linked list. But _cairo_clip_get_region() will succeed if intersection between non-rectilinear and rectilinear paths can be reduced to an aligned box. One very simple example for this, you can think about clip which is consist of two paths which will be intersected, a rectangle contained in a round rectangle. _cairo_clip_get_boxes() will fail, but _cairo_clip_get_region() will succeed. I have already fixed this but maybe you guys can help me making a decision between two choices. Plan A : Use _cairo_clip_get_region on stage 1 (instead of _cairo_clip_to_boxes) Plan B : Use _cairo_clip_get_boxes on stage 4 (instead of _cairo_clip_get_region) Indeed, I need more work on plan B due to handling of unbounded ops and anti-alias. (It seems that current implementation also does not handle those cases properly) And one last question. Are there any plans to implement geometry clipping (to avoid using clip mask) by polygon clipper or tessellator or scan rasterizer? Thanks in advance. -- Best Regards, Taekyun Kim </body> </html>