lib/gfxpoly/wind.h

   1 #ifndef __wind_h__
   2 #define __wind_h__
   3
   4 /* Every segment has an original direction, which is the direction
   5    the segment had in the input data.
   6    as our scanline moves from minimum y to maximum y, "DOWN" means
   7    the the (original) segment's y2 is larger than its y1 */
   8 typedef enum {DIR_UP, DIR_DOWN, DIR_UNKNOWN} segment_dir_t;
   9
  10 #define DIR_INVERT(d) ((d)^(DIR_UP^DIR_DOWN))
  11
  12 typedef struct _edgestyle {
  13     void*internal;
  14 } edgestyle_t;
  15
  16 extern edgestyle_t edgestyle_default;
  17
  18 typedef struct _windstate
  19 {
  20     char is_filled;
  21     int wind_nr;
  22 } windstate_t;
  23
  24 typedef struct _windcontext
  25 {
  26     int num_polygons;
  27 } windcontext_t;
  28
  29 typedef struct _windrule
  30 {
  31     windstate_t (*start)(windcontext_t* num_polygons);
  32     windstate_t (*add)(windcontext_t*context, windstate_t left, edgestyle_t*edge, segment_dir_t dir, int polygon_nr);
  33     edgestyle_t* (*diff)(windstate_t*left, windstate_t*right);
  34 } windrule_t;
  35
  36 extern windrule_t windrule_evenodd;
  37 extern windrule_t windrule_circular;
  38 extern windrule_t windrule_intersect;
  39 extern windrule_t windrule_union;
  40
  41 #endif