src/gallium/state_trackers/vega/bezier.h

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   3  * Copyright 2009 VMware, Inc.  All Rights Reserved.
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  26
  27 #ifndef BEZIER_H
  28 #define BEZIER_H
  29
  30 struct polygon;
  31 struct matrix;
  32
  33 struct bezier {
  34     float x1, y1;
  35     float x2, y2;
  36     float x3, y3;
  37     float x4, y4;
  38 };
  39
  40
  41 #define BEZIER_DEFAULT_ERROR 0.01
  42
  43 /* kappa as being l of a circle with r = 1, we can emulate any
  44  * circle of radius r by using the formula
  45  * l = r . kappa
  46  * More at:
  47  * http://www.whizkidtech.redprince.net/bezier/circle/ */
  48 #define KAPPA 0.5522847498
  49
  50 void bezier_init(struct bezier *bez,
  51                  float x1, float y1,
  52                  float x2, float y2,
  53                  float x3, float y3,
  54                  float x4, float y4);
  55
  56 struct polygon *bezier_to_polygon(struct bezier *bez);
  57 void bezier_add_to_polygon(const struct bezier *bez,
  58                            struct polygon *poly);
  59 float bezier_length(struct bezier *bez, float error);
  60 void bezier_transform(struct bezier *bez,
  61                       struct matrix *mat);
  62
  63 int bezier_translate_by_normal(struct bezier *b,
  64                                struct bezier *curves,
  65                                int max_curves,
  66                                float normal_len,
  67                                float threshold);
  68 void bezier_bounds(const struct bezier *bez,
  69                    float *bounds/*x/y/width/height*/);
  70 void bezier_exact_bounds(const struct bezier *bez,
  71                          float *bounds/*x/y/width/height*/);
  72
  73 void bezier_start_tangent(const struct bezier *bez,
  74                           float *tangent);
  75
  76 void bezier_point_at_length(struct bezier *bez, float length,
  77                             float *point, float *normal);
  78 void bezier_point_at_t(struct bezier *bez, float t,
  79                        float *point, float *normal);
  80
  81 #endif