mirror of
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93d0de1d9a
Reviewed-by: Neil Roberts <neil@linux.intel.com> (cherry picked from commit a99512e5798e48ffa3a9a1a7eb98bc55647ee1b6)
106 lines
3.8 KiB
C
106 lines
3.8 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2008,2009 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 under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*
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*/
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#if !defined(__COGL_H_INSIDE__) && !defined(COGL_COMPILATION)
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#error "Only <cogl/cogl.h> can be included directly."
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#endif
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#ifndef __COGL_PATH_H__
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#define __COGL_PATH_H__
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#include <cogl/cogl-types.h>
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G_BEGIN_DECLS
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/**
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* SECTION:cogl-paths
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* @short_description: Functions for constructing and drawing 2D paths.
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*
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* There are two levels on which drawing with cogl-paths can be used.
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* The highest level functions construct various simple primitive
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* shapes to be either filled or stroked. Using a lower-level set of
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* functions more complex and arbitrary paths can be constructed by
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* concatenating straight line, bezier curve and arc segments.
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*
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* When constructing arbitrary paths, the current pen location is
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* initialized using the move_to command. The subsequent path segments
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* implicitly use the last pen location as their first vertex and move
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* the pen location to the last vertex they produce at the end. Also
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* there are special versions of functions that allow specifying the
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* vertices of the path segments relative to the last pen location
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* rather then in the absolute coordinates.
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*/
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typedef struct _CoglPath CoglPath;
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#define COGL_PATH(obj) ((CoglPath *)(obj))
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/**
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* CoglPathFillRule:
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* @COGL_PATH_FILL_RULE_NON_ZERO: Each time the line crosses an edge of
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* the path from left to right one is added to a counter and each time
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* it crosses from right to left the counter is decremented. If the
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* counter is non-zero then the point will be filled. See <xref
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* linkend="fill-rule-non-zero"/>.
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* @COGL_PATH_FILL_RULE_EVEN_ODD: If the line crosses an edge of the
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* path an odd number of times then the point will filled, otherwise
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* it won't. See <xref linkend="fill-rule-even-odd"/>.
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*
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* #CoglPathFillRule is used to determine how a path is filled. There
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* are two options - 'non-zero' and 'even-odd'. To work out whether any
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* point will be filled imagine drawing an infinetely long line in any
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* direction from that point. The number of times and the direction
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* that the edges of the path crosses this line determines whether the
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* line is filled as described below. Any open sub paths are treated
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* as if there was an extra line joining the first point and the last
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* point.
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*
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* The default fill rule is %COGL_PATH_FILL_RULE_EVEN_ODD. The fill
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* rule is attached to the current path so preserving a path with
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* cogl_get_path() also preserves the fill rule. Calling
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* cogl_path_new() resets the current fill rule to the default.
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*
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* <figure id="fill-rule-non-zero">
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* <title>Example of filling various paths using the non-zero rule</title>
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* <graphic fileref="fill-rule-non-zero.png" format="PNG"/>
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* </figure>
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*
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* <figure id="fill-rule-even-odd">
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* <title>Example of filling various paths using the even-odd rule</title>
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* <graphic fileref="fill-rule-even-odd.png" format="PNG"/>
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* </figure>
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*
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* Since: 1.4
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*/
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typedef enum {
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COGL_PATH_FILL_RULE_NON_ZERO,
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COGL_PATH_FILL_RULE_EVEN_ODD
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} CoglPathFillRule;
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G_END_DECLS
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#include "cogl-path-functions.h"
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#endif /* __COGL_PATH_H__ */
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