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/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
/* 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 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-boxes-private.h"
#include "cairo-contour-private.h"
#include "cairo-error-private.h"
#define DEBUG_POLYGON 0
#if DEBUG_POLYGON && !NDEBUG
static void
assert_last_edge_is_valid(cairo_polygon_t *polygon,
const cairo_box_t *limit)
{
cairo_edge_t *edge;
cairo_fixed_t x;
edge = &polygon->edges[polygon->num_edges-1];
assert (edge->bottom > edge->top);
assert (edge->top >= limit->p1.y);
assert (edge->bottom <= limit->p2.y);
x = _cairo_edge_compute_intersection_x_for_y (&edge->line.p1,
&edge->line.p2,
edge->top);
assert (x >= limit->p1.x);
assert (x <= limit->p2.x);
edge->bottom);
}
#else
#define assert_last_edge_is_valid(p, l)
#endif
_cairo_polygon_add_edge (cairo_polygon_t *polygon,
const cairo_point_t *p1,
const cairo_point_t *p2,
int dir);
void
_cairo_polygon_limit (cairo_polygon_t *polygon,
const cairo_box_t *limits,
int num_limits)
int n;
polygon->limits = limits;
polygon->num_limits = num_limits;
if (polygon->num_limits) {
polygon->limit = limits[0];
for (n = 1; n < num_limits; n++) {
if (limits[n].p1.x < polygon->limit.p1.x)
polygon->limit.p1.x = limits[n].p1.x;
if (limits[n].p1.y < polygon->limit.p1.y)
polygon->limit.p1.y = limits[n].p1.y;
if (limits[n].p2.x > polygon->limit.p2.x)
polygon->limit.p2.x = limits[n].p2.x;
if (limits[n].p2.y > polygon->limit.p2.y)
polygon->limit.p2.y = limits[n].p2.y;
_cairo_polygon_limit_to_clip (cairo_polygon_t *polygon,
const cairo_clip_t *clip)
if (clip)
_cairo_polygon_limit (polygon, clip->boxes, clip->num_boxes);
else
_cairo_polygon_limit (polygon, 0, 0);
_cairo_polygon_init (cairo_polygon_t *polygon,
VG (VALGRIND_MAKE_MEM_UNDEFINED (polygon, sizeof (cairo_polygon_t)));
polygon->status = CAIRO_STATUS_SUCCESS;
polygon->num_edges = 0;
polygon->edges = polygon->edges_embedded;
polygon->edges_size = ARRAY_LENGTH (polygon->edges_embedded);
polygon->extents.p1.x = polygon->extents.p1.y = INT32_MAX;
polygon->extents.p2.x = polygon->extents.p2.y = INT32_MIN;
_cairo_polygon_limit (polygon, limits, num_limits);
_cairo_polygon_init_with_clip (cairo_polygon_t *polygon,
_cairo_polygon_init (polygon, clip->boxes, clip->num_boxes);
_cairo_polygon_init (polygon, 0, 0);
cairo_status_t
_cairo_polygon_init_boxes (cairo_polygon_t *polygon,
const cairo_boxes_t *boxes)
const struct _cairo_boxes_chunk *chunk;
int i;
if (boxes->num_boxes > ARRAY_LENGTH (polygon->edges_embedded)/2) {
polygon->edges_size = 2 * boxes->num_boxes;
polygon->edges = _cairo_malloc_ab (polygon->edges_size,
2*sizeof(cairo_edge_t));
if (unlikely (polygon->edges == NULL))
return polygon->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
polygon->limits = NULL;
polygon->num_limits = 0;
for (chunk = &boxes->chunks; chunk != NULL; chunk = chunk->next) {
for (i = 0; i < chunk->count; i++) {
cairo_point_t p1, p2;
p1 = chunk->base[i].p1;
p2.x = p1.x;
p2.y = chunk->base[i].p2.y;
_cairo_polygon_add_edge (polygon, &p1, &p2, 1);
p1 = chunk->base[i].p2;
p2.y = chunk->base[i].p1.y;
return polygon->status;
_cairo_polygon_init_box_array (cairo_polygon_t *polygon,
cairo_box_t *boxes,
int num_boxes)
if (num_boxes > ARRAY_LENGTH (polygon->edges_embedded)/2) {
polygon->edges_size = 2 * num_boxes;
for (i = 0; i < num_boxes; i++) {
p1 = boxes[i].p1;
p2.y = boxes[i].p2.y;
p1 = boxes[i].p2;
p2.y = boxes[i].p1.y;
_cairo_polygon_fini (cairo_polygon_t *polygon)
if (polygon->edges != polygon->edges_embedded)
free (polygon->edges);
/* make room for at least one more edge */
static cairo_bool_t
_cairo_polygon_grow (cairo_polygon_t *polygon)
cairo_edge_t *new_edges;
int old_size = polygon->edges_size;
int new_size = 4 * old_size;
if (CAIRO_INJECT_FAULT ()) {
polygon->status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
return FALSE;
if (polygon->edges == polygon->edges_embedded) {
new_edges = _cairo_malloc_ab (new_size, sizeof (cairo_edge_t));
if (new_edges != NULL)
memcpy (new_edges, polygon->edges, old_size * sizeof (cairo_edge_t));
} else {
new_edges = _cairo_realloc_ab (polygon->edges,
new_size, sizeof (cairo_edge_t));
if (unlikely (new_edges == NULL)) {
polygon->edges = new_edges;
polygon->edges_size = new_size;
return TRUE;
_add_edge (cairo_polygon_t *polygon,
int top, int bottom,
int dir)
assert (top < bottom);
if (unlikely (polygon->num_edges == polygon->edges_size)) {
if (! _cairo_polygon_grow (polygon))
return;
edge = &polygon->edges[polygon->num_edges++];
edge->line.p1 = *p1;
edge->line.p2 = *p2;
edge->top = top;
edge->bottom = bottom;
edge->dir = dir;
if (top < polygon->extents.p1.y)
polygon->extents.p1.y = top;
if (bottom > polygon->extents.p2.y)
polygon->extents.p2.y = bottom;
if (p1->x < polygon->extents.p1.x || p1->x > polygon->extents.p2.x) {
cairo_fixed_t x = p1->x;
if (top != p1->y)
x = _cairo_edge_compute_intersection_x_for_y (p1, p2, top);
if (x < polygon->extents.p1.x)
polygon->extents.p1.x = x;
if (x > polygon->extents.p2.x)
polygon->extents.p2.x = x;
if (p2->x < polygon->extents.p1.x || p2->x > polygon->extents.p2.x) {
cairo_fixed_t x = p2->x;
if (bottom != p2->y)
x = _cairo_edge_compute_intersection_x_for_y (p1, p2, bottom);
_add_clipped_edge (cairo_polygon_t *polygon,
const int top, const int bottom,
const int dir)
cairo_point_t bot_left, top_right;
cairo_fixed_t top_y, bot_y;
for (n = 0; n < polygon->num_limits; n++) {
const cairo_box_t *limits = &polygon->limits[n];
cairo_fixed_t pleft, pright;
if (top >= limits->p2.y)
continue;
if (bottom <= limits->p1.y)
bot_left.x = limits->p1.x;
bot_left.y = limits->p2.y;
top_right.x = limits->p2.x;
top_right.y = limits->p1.y;
/* The useful region */
top_y = MAX (top, limits->p1.y);
bot_y = MIN (bottom, limits->p2.y);
/* The projection of the edge on the horizontal axis */
pleft = MIN (p1->x, p2->x);
pright = MAX (p1->x, p2->x);
if (limits->p1.x <= pleft && pright <= limits->p2.x) {
/* Projection of the edge completely contained in the box:
* clip vertically by restricting top and bottom */
_add_edge (polygon, p1, p2, top_y, bot_y, dir);
assert_last_edge_is_valid (polygon, limits);
} else if (pright <= limits->p1.x) {
/* Projection of the edge to the left of the box:
* replace with the left side of the box (clipped top/bottom) */
_add_edge (polygon, &limits->p1, &bot_left, top_y, bot_y, dir);
} else if (limits->p2.x <= pleft) {
/* Projection of the edge to the right of the box:
* replace with the right side of the box (clipped top/bottom) */
_add_edge (polygon, &top_right, &limits->p2, top_y, bot_y, dir);
/* The edge and the box intersect in a generic way */
cairo_fixed_t left_y, right_y;
cairo_bool_t top_left_to_bottom_right;
/*
* The edge intersects the lines corresponding to the left
* and right sides of the limit box at left_y and right_y,
* but we need to add edges for the range from top_y to
* bot_y.
* For both intersections, there are three cases:
* 1) It is outside the vertical range of the limit
* box. In this case we can simply further clip the
* edge we will be emitting (i.e. restrict its
* top/bottom limits to those of the limit box).
* 2) It is inside the vertical range of the limit
* box. In this case, we need to add the vertical edge
* connecting the correct vertex to the intersection,
* in order to preserve the winding count.
* 3) It is exactly on the box. In this case, do nothing.
* These operations restrict the active range (stored in
* top_y/bot_y) so that the p1-p2 edge is completely
* inside the box if it is clipped to this vertical range.
top_left_to_bottom_right = (p1->x <= p2->x) == (p1->y <= p2->y);
if (top_left_to_bottom_right) {
if (pleft >= limits->p1.x) {
left_y = top_y;
left_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
limits->p1.x);
if (_cairo_edge_compute_intersection_x_for_y (p1, p2, left_y) < limits->p1.x)
left_y++;
left_y = MIN (left_y, bot_y);
if (top_y < left_y) {
_add_edge (polygon, &limits->p1, &bot_left,
top_y, left_y, dir);
top_y = left_y;
if (pright <= limits->p2.x) {
right_y = bot_y;
right_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,
limits->p2.x);
if (_cairo_edge_compute_intersection_x_for_y (p1, p2, right_y) > limits->p2.x)
right_y--;
right_y = MAX (right_y, top_y);
if (bot_y > right_y) {
_add_edge (polygon, &top_right, &limits->p2,
right_y, bot_y, dir);
bot_y = right_y;
right_y = top_y;
right_y++;
right_y = MIN (right_y, bot_y);
if (top_y < right_y) {
top_y, right_y, dir);
top_y = right_y;
left_y = bot_y;
left_y--;
left_y = MAX (left_y, top_y);
if (bot_y > left_y) {
left_y, bot_y, dir);
bot_y = left_y;
if (top_y != bot_y) {
/* drop horizontal edges */
if (p1->y == p2->y)
if (p1->y > p2->y) {
const cairo_point_t *t;
t = p1, p1 = p2, p2 = t;
dir = -dir;
if (p2->y <= polygon->limit.p1.y)
if (p1->y >= polygon->limit.p2.y)
_add_clipped_edge (polygon, p1, p2, p1->y, p2->y, dir);
} else
_add_edge (polygon, p1, p2, p1->y, p2->y, dir);
_cairo_polygon_add_external_edge (void *polygon,
const cairo_point_t *p2)
_cairo_polygon_add_edge (polygon, p1, p2, 1);
return _cairo_polygon_status (polygon);
_cairo_polygon_add_line (cairo_polygon_t *polygon,
const cairo_line_t *line,
if (line->p1.y == line->p2.y)
return CAIRO_STATUS_SUCCESS;
if (bottom <= top)
if (line->p2.y <= polygon->limit.p1.y)
if (line->p1.y >= polygon->limit.p2.y)
_add_clipped_edge (polygon, &line->p1, &line->p2, top, bottom, dir);
_add_edge (polygon, &line->p1, &line->p2, top, bottom, dir);
_cairo_polygon_add_contour (cairo_polygon_t *polygon,
const cairo_contour_t *contour)
const struct _cairo_contour_chain *chain;
const cairo_point_t *prev = NULL;
if (contour->chain.num_points <= 1)
return CAIRO_INT_STATUS_SUCCESS;
prev = &contour->chain.points[0];
for (chain = &contour->chain; chain; chain = chain->next) {
for (i = 0; i < chain->num_points; i++) {
_cairo_polygon_add_edge (polygon, prev, &chain->points[i],
contour->direction);
prev = &chain->points[i];
_cairo_polygon_translate (cairo_polygon_t *polygon, int dx, int dy)
dx = _cairo_fixed_from_int (dx);
dy = _cairo_fixed_from_int (dy);
polygon->extents.p1.x += dx;
polygon->extents.p2.x += dx;
polygon->extents.p1.y += dy;
polygon->extents.p2.y += dy;
for (n = 0; n < polygon->num_edges; n++) {
cairo_edge_t *e = &polygon->edges[n];
e->top += dy;
e->bottom += dy;
e->line.p1.x += dx;
e->line.p2.x += dx;
e->line.p1.y += dy;
e->line.p2.y += dy;