diff options
Diffstat (limited to 'src/cairo-polygon.c')
| -rw-r--r-- | src/cairo-polygon.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/cairo-polygon.c b/src/cairo-polygon.c new file mode 100644 index 00000000..70817bd9 --- /dev/null +++ b/src/cairo-polygon.c @@ -0,0 +1,175 @@ +/* + * Copyright © 2002 USC, Information Sciences Institute + * + * Permission to use, copy, modify, distribute, and sell this software + * and its documentation for any purpose is hereby granted without + * fee, provided that the above copyright notice appear in all copies + * and that both that copyright notice and this permission notice + * appear in supporting documentation, and that the name of the + * University of Southern California not be used in advertising or + * publicity pertaining to distribution of the software without + * specific, written prior permission. The University of Southern + * California makes no representations about the suitability of this + * software for any purpose. It is provided "as is" without express + * or implied warranty. + * + * THE UNIVERSITY OF SOUTHERN CALIFORNIA DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE UNIVERSITY OF + * SOUTHERN CALIFORNIA BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS + * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, + * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + * Author: Carl D. Worth <cworth@isi.edu> + */ + +#include <stdlib.h> +#include "cairoint.h" + +#define CAIRO_POLYGON_GROWTH_INC 10 + +/* private functions */ + +static cairo_status_t +_cairo_polygon_grow_by (cairo_polygon_t *polygon, int additional); + +static void +_cairo_polygon_set_last_point (cairo_polygon_t *polygon, XPointFixed *pt); + + +void +_cairo_polygon_init (cairo_polygon_t *polygon) +{ + polygon->num_edges = 0; + + polygon->edges_size = 0; + polygon->edges = NULL; + + polygon->first_pt_defined = 0; + polygon->last_pt_defined = 0; + + polygon->closed = 0; +} + +void +_cairo_polygon_fini (cairo_polygon_t *polygon) +{ + if (polygon->edges_size) { + free (polygon->edges); + polygon->edges = NULL; + polygon->edges_size = 0; + polygon->num_edges = 0; + } + + polygon->first_pt_defined = 0; + polygon->last_pt_defined = 0; + + polygon->closed = 0; +} + +static cairo_status_t +_cairo_polygon_grow_by (cairo_polygon_t *polygon, int additional) +{ + cairo_edge_t *new_edges; + int old_size = polygon->edges_size; + int new_size = polygon->num_edges + additional; + + if (new_size <= polygon->edges_size) { + return CAIRO_STATUS_SUCCESS; + } + + polygon->edges_size = new_size; + new_edges = realloc (polygon->edges, polygon->edges_size * sizeof (cairo_edge_t)); + + if (new_edges == NULL) { + polygon->edges_size = old_size; + return CAIRO_STATUS_NO_MEMORY; + } + + polygon->edges = new_edges; + + return CAIRO_STATUS_SUCCESS; +} + +static void +_cairo_polygon_set_last_point (cairo_polygon_t *polygon, XPointFixed *pt) +{ + polygon->last_pt = *pt; + polygon->last_pt_defined = 1; +} + +cairo_status_t +_cairo_polygon_add_edge (cairo_polygon_t *polygon, XPointFixed *p1, XPointFixed *p2) +{ + cairo_status_t status; + cairo_edge_t *edge; + + if (! polygon->first_pt_defined) { + polygon->first_pt = *p1; + polygon->first_pt_defined = 1; + polygon->closed = 0; + } + + /* drop horizontal edges */ + if (p1->y == p2->y) { + goto DONE; + } + + if (polygon->num_edges >= polygon->edges_size) { + status = _cairo_polygon_grow_by (polygon, CAIRO_POLYGON_GROWTH_INC); + if (status) { + return status; + } + } + + edge = &polygon->edges[polygon->num_edges]; + if (p1->y < p2->y) { + edge->edge.p1 = *p1; + edge->edge.p2 = *p2; + edge->clockWise = True; + } else { + edge->edge.p1 = *p2; + edge->edge.p2 = *p1; + edge->clockWise = False; + } + + polygon->num_edges++; + + DONE: + _cairo_polygon_set_last_point (polygon, p2); + + return CAIRO_STATUS_SUCCESS; +} + +cairo_status_t +_cairo_polygon_add_point (cairo_polygon_t *polygon, XPointFixed *pt) +{ + cairo_status_t status = CAIRO_STATUS_SUCCESS; + + if (polygon->last_pt_defined) { + status = _cairo_polygon_add_edge (polygon, &polygon->last_pt, pt); + } else { + _cairo_polygon_set_last_point (polygon, pt); + } + + return status; +} + +cairo_status_t +_cairo_polygon_close (cairo_polygon_t *polygon) +{ + cairo_status_t status; + + if (polygon->closed == 0 && polygon->last_pt_defined) { + status = _cairo_polygon_add_edge (polygon, &polygon->last_pt, &polygon->first_pt); + if (status) + return status; + + polygon->closed = 1; + polygon->first_pt_defined = 0; + } + + return CAIRO_STATUS_SUCCESS; +} |