summaryrefslogtreecommitdiff
path: root/libs/cairo-1.16.0/src/cairo-hull.c
diff options
context:
space:
mode:
Diffstat (limited to 'libs/cairo-1.16.0/src/cairo-hull.c')
-rw-r--r--libs/cairo-1.16.0/src/cairo-hull.c235
1 files changed, 0 insertions, 235 deletions
diff --git a/libs/cairo-1.16.0/src/cairo-hull.c b/libs/cairo-1.16.0/src/cairo-hull.c
deleted file mode 100644
index c655933..0000000
--- a/libs/cairo-1.16.0/src/cairo-hull.c
+++ /dev/null
@@ -1,235 +0,0 @@
-/* cairo - a vector graphics library with display and print output
- *
- * Copyright © 2003 University of Southern California
- *
- * This library is free software; you can redistribute it and/or
- * modify it either under the terms of the GNU Lesser General Public
- * License version 2.1 as published by the Free Software Foundation
- * (the "LGPL") or, at your option, under the terms of the Mozilla
- * Public License Version 1.1 (the "MPL"). If you do not alter this
- * notice, a recipient may use your version of this file under either
- * the MPL or the LGPL.
- *
- * You should have received a copy of the LGPL along with this library
- * in the file COPYING-LGPL-2.1; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
- * You should have received a copy of the MPL along with this library
- * in the file COPYING-MPL-1.1
- *
- * The contents of this file are subject to the Mozilla Public License
- * Version 1.1 (the "License"); you may not use this file except in
- * compliance with the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
- * OF ANY KIND, either express or implied. See the LGPL or the MPL for
- * the specific language governing rights and limitations.
- *
- * The Original Code is the cairo graphics library.
- *
- * The Initial Developer of the Original Code is University of Southern
- * California.
- *
- * Contributor(s):
- * Carl D. Worth <cworth@cworth.org>
- */
-
-#include "cairoint.h"
-
-#include "cairo-error-private.h"
-#include "cairo-slope-private.h"
-
-typedef struct cairo_hull {
- cairo_point_t point;
- cairo_slope_t slope;
- int discard;
- int id;
-} cairo_hull_t;
-
-static void
-_cairo_hull_init (cairo_hull_t *hull,
- cairo_pen_vertex_t *vertices,
- int num_vertices)
-{
- cairo_point_t *p, *extremum, tmp;
- int i;
-
- extremum = &vertices[0].point;
- for (i = 1; i < num_vertices; i++) {
- p = &vertices[i].point;
- if (p->y < extremum->y || (p->y == extremum->y && p->x < extremum->x))
- extremum = p;
- }
- /* Put the extremal point at the beginning of the array */
- tmp = *extremum;
- *extremum = vertices[0].point;
- vertices[0].point = tmp;
-
- for (i = 0; i < num_vertices; i++) {
- hull[i].point = vertices[i].point;
- _cairo_slope_init (&hull[i].slope, &hull[0].point, &hull[i].point);
-
- /* give each point a unique id for later comparison */
- hull[i].id = i;
-
- /* Don't discard by default */
- hull[i].discard = 0;
-
- /* Discard all points coincident with the extremal point */
- if (i != 0 && hull[i].slope.dx == 0 && hull[i].slope.dy == 0)
- hull[i].discard = 1;
- }
-}
-
-static inline cairo_int64_t
-_slope_length (cairo_slope_t *slope)
-{
- return _cairo_int64_add (_cairo_int32x32_64_mul (slope->dx, slope->dx),
- _cairo_int32x32_64_mul (slope->dy, slope->dy));
-}
-
-static int
-_cairo_hull_vertex_compare (const void *av, const void *bv)
-{
- cairo_hull_t *a = (cairo_hull_t *) av;
- cairo_hull_t *b = (cairo_hull_t *) bv;
- int ret;
-
- /* Some libraries are reported to actually compare identical
- * pointers and require the result to be 0. This is the crazy world we
- * have to live in.
- */
- if (a == b)
- return 0;
-
- ret = _cairo_slope_compare (&a->slope, &b->slope);
-
- /*
- * In the case of two vertices with identical slope from the
- * extremal point discard the nearer point.
- */
- if (ret == 0) {
- int cmp;
-
- cmp = _cairo_int64_cmp (_slope_length (&a->slope),
- _slope_length (&b->slope));
-
- /*
- * Use the points' ids to ensure a well-defined ordering,
- * and avoid setting discard on both points.
- */
- if (cmp < 0 || (cmp == 0 && a->id < b->id)) {
- a->discard = 1;
- ret = -1;
- } else {
- b->discard = 1;
- ret = 1;
- }
- }
-
- return ret;
-}
-
-static int
-_cairo_hull_prev_valid (cairo_hull_t *hull, int num_hull, int index)
-{
- /* hull[0] is always valid, and we never need to wraparound, (if
- * we are passed an index of 0 here, then the calling loop is just
- * about to terminate). */
- if (index == 0)
- return 0;
-
- do {
- index--;
- } while (hull[index].discard);
-
- return index;
-}
-
-static int
-_cairo_hull_next_valid (cairo_hull_t *hull, int num_hull, int index)
-{
- do {
- index = (index + 1) % num_hull;
- } while (hull[index].discard);
-
- return index;
-}
-
-static void
-_cairo_hull_eliminate_concave (cairo_hull_t *hull, int num_hull)
-{
- int i, j, k;
- cairo_slope_t slope_ij, slope_jk;
-
- i = 0;
- j = _cairo_hull_next_valid (hull, num_hull, i);
- k = _cairo_hull_next_valid (hull, num_hull, j);
-
- do {
- _cairo_slope_init (&slope_ij, &hull[i].point, &hull[j].point);
- _cairo_slope_init (&slope_jk, &hull[j].point, &hull[k].point);
-
- /* Is the angle formed by ij and jk concave? */
- if (_cairo_slope_compare (&slope_ij, &slope_jk) >= 0) {
- if (i == k)
- return;
- hull[j].discard = 1;
- j = i;
- i = _cairo_hull_prev_valid (hull, num_hull, j);
- } else {
- i = j;
- j = k;
- k = _cairo_hull_next_valid (hull, num_hull, j);
- }
- } while (j != 0);
-}
-
-static void
-_cairo_hull_to_pen (cairo_hull_t *hull, cairo_pen_vertex_t *vertices, int *num_vertices)
-{
- int i, j = 0;
-
- for (i = 0; i < *num_vertices; i++) {
- if (hull[i].discard)
- continue;
- vertices[j++].point = hull[i].point;
- }
-
- *num_vertices = j;
-}
-
-/* Given a set of vertices, compute the convex hull using the Graham
- scan algorithm. */
-cairo_status_t
-_cairo_hull_compute (cairo_pen_vertex_t *vertices, int *num_vertices)
-{
- cairo_hull_t hull_stack[CAIRO_STACK_ARRAY_LENGTH (cairo_hull_t)];
- cairo_hull_t *hull;
- int num_hull = *num_vertices;
-
- if (CAIRO_INJECT_FAULT ())
- return _cairo_error (CAIRO_STATUS_NO_MEMORY);
-
- if (num_hull > ARRAY_LENGTH (hull_stack)) {
- hull = _cairo_malloc_ab (num_hull, sizeof (cairo_hull_t));
- if (unlikely (hull == NULL))
- return _cairo_error (CAIRO_STATUS_NO_MEMORY);
- } else {
- hull = hull_stack;
- }
-
- _cairo_hull_init (hull, vertices, num_hull);
-
- qsort (hull + 1, num_hull - 1,
- sizeof (cairo_hull_t), _cairo_hull_vertex_compare);
-
- _cairo_hull_eliminate_concave (hull, num_hull);
-
- _cairo_hull_to_pen (hull, vertices, num_vertices);
-
- if (hull != hull_stack)
- free (hull);
-
- return CAIRO_STATUS_SUCCESS;
-}
generated by cgit v1.2.1 (git 2.18.0) at 2024-11-01 19:40:19 +0000