+/* Every segment has an original direction, which is the direction
+ the segment had in the input data.
+ as our scanline moves from minimum y to maximum y, "DOWN" means
+ the the (original) segment's y2 is larger than its y1 */
+typedef enum {DIR_UP, DIR_DOWN, DIR_UNKNOWN} segment_dir_t;
+
+typedef struct _edgestyle {
+ void*internal;
+} edgestyle_t;
+
+extern edgestyle_t edgestyle_default;
+
+typedef struct _windstate
+{
+ char is_filled;
+ int wind_nr;
+} windstate_t;
+
+typedef struct _windcontext
+{
+ int num_polygons;
+} windcontext_t;
+
+typedef struct _windrule
+{
+ windstate_t (*start)(windcontext_t* num_polygons);
+ windstate_t (*add)(windcontext_t*context, windstate_t left, edgestyle_t*edge, segment_dir_t dir, int polygon_nr);
+ edgestyle_t* (*diff)(windstate_t*left, windstate_t*right);
+} windrule_t;