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571a27b4fc
This adds a new GPU accelerated backend for Cairo based on the Cogl 3D graphics API. This backend aims to support Cairo in a way that translates as naturally as possible to using a GPU, it does not strive to compete with the anti-aliasing quality of the image backend if it can't be done efficiently using the GPU - raw performance isn't the only metric of concern, so is power usage. As an overview of how the backend works: - fills are handled by tessellating paths into triangles - the backend has an extra fill_rectangle drawing operation so we have a fast-path for drawing rectangles which are so common. - strokes are also tessellated into triangles. - stroke and fill tessellations are cached to avoid the cpu overhead of tessellation and cost of upload given that its common for apps to re-draw the same path multiple times. The tessellations can survive translations and rotations increasing the probability that they can be re-used. - sources and masks are handled using multi-texturing. - clipping is handled with a scissor and the stencil buffer which we're careful to only update when they really change. - linear gradients are rendered to a 1d texture using a triangle strip + interpolating color attributes. All cairo extend modes are handled by corresponding texture sampler wrap modes without needing programmable fragment processing. - antialiasing should be handled using Cogl's multisampling API XXX: This is a work in progress!! TODO: - handle at least basic radial gradients (No need to handle full pdf semantics, since css, svg and canvas only allow radial gradients defined as one circle + a point that must lie within the first circle.) - currently we fall back to pixman for radial gradients. - support glyph rendering with a decent glyph cache design. The current plan is a per scaled-font growable cache texture + a scratch cache for one-shot/short-lived glyphs. - decide how to handle npot textures when lacking hardware support. Current plan is to add a transparent border to npot textures and use CLAMP_TO_EDGE for the default EXTEND_NONE semantics. For anything else we can allocate a shadow npot texture and scale the original to fit that so we can map extend modes to texture sampler modes. |
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| .. | ||
| .gitignore | ||
| aclocal.cairo.m4 | ||
| aclocal.compare.m4 | ||
| aclocal.enable.m4 | ||
| aclocal.float.m4 | ||
| aclocal.gtk-doc.m4 | ||
| aclocal.makefile.m4 | ||
| aclocal.pkg.m4 | ||
| configure.ac.analysis | ||
| configure.ac.features | ||
| configure.ac.noversion | ||
| configure.ac.pthread | ||
| configure.ac.system | ||
| configure.ac.tools | ||
| configure.ac.version | ||
| configure.ac.warnings | ||
| Makefile.am.analysis | ||
| Makefile.am.changelog | ||
| Makefile.am.common | ||
| Makefile.am.gtk-doc | ||
| Makefile.am.releasing | ||
| Makefile.win32.common | ||
| Makefile.win32.features | ||
| Makefile.win32.features-h | ||