BOUNDARY_HALF_WAY

#define BOUNDARY_HALF_WAY 127

enum BoundaryType

typedef enum
{
  BOUNDARY_WITHIN_BOUNDS,
  BOUNDARY_IGNORE_BOUNDS
} BoundaryType;

BoundSeg

typedef struct {
  gint   x1;
  gint   y1;
  gint   x2;
  gint   y2;
  guint  open    : 1;
  guint  visited : 1;
} BoundSeg;

boundary_find ()

BoundSeg*           boundary_find                       (PixelRegion *maskPR,
                                                         BoundaryType type,
                                                         gint x1,
                                                         gint y1,
                                                         gint x2,
                                                         gint y2,
                                                         guchar threshold,
                                                         gint *num_segs);

This function returns an array of BoundSeg's which describe all outlines along pixel value threahold, optionally within specified bounds instead of the whole region.

The maskPR paramater can be any PixelRegion. If the region has more than 1 bytes/pixel, the last byte of each pixel is used to determine the boundary outline.

boundary_sort ()

BoundSeg*           boundary_sort                       (const BoundSeg *segs,
                                                         gint num_segs,
                                                         gint *num_groups);

This function takes an array of BoundSeg's as returned by boundary_find() and sorts it by contiguous groups. The returned array contains markers consisting of -1 coordinates and is num_groups elements longer than segs.

boundary_simplify ()

BoundSeg*           boundary_simplify                   (BoundSeg *sorted_segs,
                                                         gint num_groups,
                                                         gint *num_segs);

This function takes an array of BoundSeg's which has been sorted with boundary_sort() and reduces the number of segments while preserving the general shape as close as possible.