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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.
54 lines
1.9 KiB
C
54 lines
1.9 KiB
C
/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2011 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.og/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* Contributor(s):
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* Robert Bragg <robert@linux.intel.com>
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*/
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#ifndef CAIRO_COGL_UTILS_PRIVATE_H
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#define CAIRO_COGL_UTILS_PRIVATE_H
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#include "cairo-path-fixed-private.h"
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#include <cogl/cogl2-experimental.h>
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CoglPath *
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_cairo_cogl_util_path_from_cairo (const cairo_path_fixed_t *path,
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cairo_fill_rule_t fill_rule,
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float tolerance);
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int
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_cairo_cogl_util_next_p2 (int a);
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#define CAIRO_FIXED_ONE_FLOAT ((float)(1 << CAIRO_FIXED_FRAC_BITS))
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static inline float
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_cairo_cogl_util_fixed_to_float (cairo_fixed_t f)
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{
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return ((float) f) / CAIRO_FIXED_ONE_FLOAT;
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}
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#endif /* CAIRO_COGL_UTILS_PRIVATE_H */
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