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/* cairo - a vector graphics library with display and print output
*
* Copyright © 2002 University of Southern California
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* 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);
void
_cairo_polygon_init (cairo_polygon_t *polygon)
{
polygon->num_edges = 0;
polygon->edges_size = 0;
polygon->edges = NULL;
polygon->has_current_point = 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->has_current_point = 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;
}
cairo_status_t
_cairo_polygon_add_edge (cairo_polygon_t *polygon, cairo_point_t *p1, cairo_point_t *p2)
{
cairo_status_t status;
cairo_edge_t *edge;
/* 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 = 1;
} else {
edge->edge.p1 = *p2;
edge->edge.p2 = *p1;
edge->clockWise = 0;
}
polygon->num_edges++;
DONE:
_cairo_polygon_move_to (polygon, p2);
return CAIRO_STATUS_SUCCESS;
}
cairo_status_t
_cairo_polygon_move_to (cairo_polygon_t *polygon, cairo_point_t *point)
{
if (! polygon->has_current_point)
polygon->first_point = *point;
polygon->current_point = *point;
polygon->has_current_point = 1;
return CAIRO_STATUS_SUCCESS;
}
cairo_status_t
_cairo_polygon_line_to (cairo_polygon_t *polygon, cairo_point_t *point)
{
cairo_status_t status = CAIRO_STATUS_SUCCESS;
if (polygon->has_current_point) {
status = _cairo_polygon_add_edge (polygon, &polygon->current_point, point);
} else {
_cairo_polygon_move_to (polygon, point);
}
return status;
}
cairo_status_t
_cairo_polygon_close (cairo_polygon_t *polygon)
{
cairo_status_t status;
if (polygon->has_current_point) {
status = _cairo_polygon_add_edge (polygon,
&polygon->current_point,
&polygon->first_point);
if (status)
return status;
polygon->has_current_point = 0;
}
return CAIRO_STATUS_SUCCESS;
}
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