Painting an image surface into itself in order to scroll it
Nicholas Allen <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <[email protected]> |
Hi, If I create an image surface and then try to scroll it by painting it into itself then it works as long as I scroll it left, right, or up but not if I scroll it down. It seems like the area is being overwritten with itself before it is fully shifted. I want to do this because my application has a viewport that gets scrolled and I cache the contents of the viewport and shift it as the user scrolls and just repaint the edge areas that get exposed rather than the whole viewport. It seems cairo has a bug that this is not possible with just one image surface if you scroll the contents downwards. I can work around it by creating 2 image surfaces and copying one to the other but I would expect cairo to be able to handle this with just one surface. I do the painting by creating a cairo_t for the bitmap, setting the surface on that to the image surface, setting up the clip etc and then calling cairo_paint. Is this a known bug? If not where should I report a bug? Kind regards, Nicholas Allen -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo