Source code
Revision control
Copy as Markdown
Other Tools
/*
* Copyright © 2004 Carl Worth
* Copyright © 2006 Red Hat, Inc.
* Copyright © 2008 Chris Wilson
* Copyright © 2011 Intel Corporation
*
* 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
*
* 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 Carl Worth
*
* Contributor(s):
* Carl D. Worth <cworth@cworth.org>
* Chris Wilson <chris@chris-wilson.co.uk>
*/
#include "cairoint.h"
#include "cairo-error-private.h"
#include "cairo-freelist-private.h"
#include "cairo-combsort-inline.h"
#include "cairo-contour-inline.h"
#include "cairo-contour-private.h"
void
_cairo_contour_init (cairo_contour_t *contour,
int direction)
{
contour->direction = direction;
contour->chain.points = contour->embedded_points;
contour->chain.next = NULL;
contour->chain.num_points = 0;
contour->chain.size_points = ARRAY_LENGTH (contour->embedded_points);
contour->tail = &contour->chain;
}
cairo_int_status_t
__cairo_contour_add_point (cairo_contour_t *contour,
const cairo_point_t *point)
{
cairo_contour_chain_t *tail = contour->tail;
cairo_contour_chain_t *next;
assert (tail->next == NULL);
next = _cairo_malloc_ab_plus_c (tail->size_points*2,
sizeof (cairo_point_t),
sizeof (cairo_contour_chain_t));
if (unlikely (next == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
next->size_points = tail->size_points*2;
next->num_points = 1;
next->points = (cairo_point_t *)(next+1);
next->next = NULL;
tail->next = next;
contour->tail = next;
next->points[0] = *point;
return CAIRO_INT_STATUS_SUCCESS;
}
static void
first_inc (cairo_contour_t *contour,
cairo_point_t **p,
cairo_contour_chain_t **chain)
{
if (*p == (*chain)->points + (*chain)->num_points) {
assert ((*chain)->next);
*chain = (*chain)->next;
*p = &(*chain)->points[0];
} else
++*p;
}
static void
last_dec (cairo_contour_t *contour,
cairo_point_t **p,
cairo_contour_chain_t **chain)
{
if (*p == (*chain)->points) {
cairo_contour_chain_t *prev;
assert (*chain != &contour->chain);
for (prev = &contour->chain; prev->next != *chain; prev = prev->next)
;
*chain = prev;
*p = &(*chain)->points[(*chain)->num_points-1];
} else
--*p;
}
void
_cairo_contour_reverse (cairo_contour_t *contour)
{
cairo_contour_chain_t *first_chain, *last_chain;
cairo_point_t *first, *last;
contour->direction = -contour->direction;
if (contour->chain.num_points <= 1)
return;
first_chain = &contour->chain;
last_chain = contour->tail;
first = &first_chain->points[0];
last = &last_chain->points[last_chain->num_points-1];
while (first != last) {
cairo_point_t p;
p = *first;
*first = *last;
*last = p;
first_inc (contour, &first, &first_chain);
last_dec (contour, &last, &last_chain);
}
}
cairo_int_status_t
_cairo_contour_add (cairo_contour_t *dst,
const cairo_contour_t *src)
{
const cairo_contour_chain_t *chain;
cairo_int_status_t status;
int i;
for (chain = &src->chain; chain; chain = chain->next) {
for (i = 0; i < chain->num_points; i++) {
status = _cairo_contour_add_point (dst, &chain->points[i]);
if (unlikely (status))
return status;
}
}
return CAIRO_INT_STATUS_SUCCESS;
}
static inline cairo_bool_t
iter_next (cairo_contour_iter_t *iter)
{
if (iter->point == &iter->chain->points[iter->chain->size_points-1]) {
iter->chain = iter->chain->next;
if (iter->chain == NULL)
return FALSE;
iter->point = &iter->chain->points[0];
return TRUE;
} else {
iter->point++;
return TRUE;
}
}
static cairo_bool_t
iter_equal (const cairo_contour_iter_t *i1,
const cairo_contour_iter_t *i2)
{
return i1->chain == i2->chain && i1->point == i2->point;
}
static void
iter_init (cairo_contour_iter_t *iter, cairo_contour_t *contour)
{
iter->chain = &contour->chain;
iter->point = &contour->chain.points[0];
}
static void
iter_init_last (cairo_contour_iter_t *iter, cairo_contour_t *contour)
{
iter->chain = contour->tail;
iter->point = &contour->tail->points[contour->tail->num_points-1];
}
static const cairo_contour_chain_t *prev_const_chain(const cairo_contour_t *contour,
const cairo_contour_chain_t *chain)
{
const cairo_contour_chain_t *prev;
if (chain == &contour->chain)
return NULL;
for (prev = &contour->chain; prev->next != chain; prev = prev->next)
;
return prev;
}
cairo_int_status_t
_cairo_contour_add_reversed (cairo_contour_t *dst,
const cairo_contour_t *src)
{
const cairo_contour_chain_t *last;
cairo_int_status_t status;
int i;
if (src->chain.num_points == 0)
return CAIRO_INT_STATUS_SUCCESS;
for (last = src->tail; last; last = prev_const_chain (src, last)) {
for (i = last->num_points-1; i >= 0; i--) {
status = _cairo_contour_add_point (dst, &last->points[i]);
if (unlikely (status))
return status;
}
}
return CAIRO_INT_STATUS_SUCCESS;
}
static cairo_uint64_t
point_distance_sq (const cairo_point_t *p1,
const cairo_point_t *p2)
{
int32_t dx = p1->x - p2->x;
int32_t dy = p1->y - p2->y;
return _cairo_int32x32_64_mul (dx, dx) + _cairo_int32x32_64_mul (dy, dy);
}
#define DELETED(p) ((p)->x == INT_MIN && (p)->y == INT_MAX)
#define MARK_DELETED(p) ((p)->x = INT_MIN, (p)->y = INT_MAX)
static cairo_bool_t
_cairo_contour_simplify_chain (cairo_contour_t *contour, const double tolerance,
const cairo_contour_iter_t *first,
const cairo_contour_iter_t *last)
{
cairo_contour_iter_t iter, furthest;
uint64_t max_error;
int x0, y0;
int nx, ny;
int count;
iter = *first;
iter_next (&iter);
if (iter_equal (&iter, last))
return FALSE;
x0 = first->point->x;
y0 = first->point->y;
nx = last->point->y - y0;
ny = x0 - last->point->x;
count = 0;
max_error = 0;
do {
cairo_point_t *p = iter.point;
if (! DELETED(p)) {
uint64_t d = (uint64_t)nx * (x0 - p->x) + (uint64_t)ny * (y0 - p->y);
if (d * d > max_error) {
max_error = d * d;
furthest = iter;
}
count++;
}
iter_next (&iter);
} while (! iter_equal (&iter, last));
if (count == 0)
return FALSE;
if (max_error > tolerance * ((uint64_t)nx * nx + (uint64_t)ny * ny)) {
cairo_bool_t simplified;
simplified = FALSE;
simplified |= _cairo_contour_simplify_chain (contour, tolerance,
first, &furthest);
simplified |= _cairo_contour_simplify_chain (contour, tolerance,
&furthest, last);
return simplified;
} else {
iter = *first;
iter_next (&iter);
do {
MARK_DELETED (iter.point);
iter_next (&iter);
} while (! iter_equal (&iter, last));
return TRUE;
}
}
void
_cairo_contour_simplify (cairo_contour_t *contour, double tolerance)
{
cairo_contour_chain_t *chain;
cairo_point_t *last = NULL;
cairo_contour_iter_t iter, furthest;
cairo_bool_t simplified;
uint64_t max = 0;
int i;
if (contour->chain.num_points <= 2)
return;
tolerance = tolerance * CAIRO_FIXED_ONE;
tolerance *= tolerance;
/* stage 1: vertex reduction */
for (chain = &contour->chain; chain; chain = chain->next) {
for (i = 0; i < chain->num_points; i++) {
if (last == NULL ||
point_distance_sq (last, &chain->points[i]) > tolerance) {
last = &chain->points[i];
} else {
MARK_DELETED (&chain->points[i]);
}
}
}
/* stage2: polygon simplification using Douglas-Peucker */
do {
last = &contour->chain.points[0];
iter_init (&furthest, contour);
max = 0;
for (chain = &contour->chain; chain; chain = chain->next) {
for (i = 0; i < chain->num_points; i++) {
uint64_t d;
if (DELETED (&chain->points[i]))
continue;
d = point_distance_sq (last, &chain->points[i]);
if (d > max) {
furthest.chain = chain;
furthest.point = &chain->points[i];
max = d;
}
}
}
assert (max);
simplified = FALSE;
iter_init (&iter, contour);
simplified |= _cairo_contour_simplify_chain (contour, tolerance,
&iter, &furthest);
iter_init_last (&iter, contour);
if (! iter_equal (&furthest, &iter))
simplified |= _cairo_contour_simplify_chain (contour, tolerance,
&furthest, &iter);
} while (simplified);
iter_init (&iter, contour);
for (chain = &contour->chain; chain; chain = chain->next) {
int num_points = chain->num_points;
chain->num_points = 0;
for (i = 0; i < num_points; i++) {
if (! DELETED(&chain->points[i])) {
if (iter.point != &chain->points[i])
*iter.point = chain->points[i];
iter.chain->num_points++;
iter_next (&iter);
}
}
}
if (iter.chain) {
cairo_contour_chain_t *next;
for (chain = iter.chain->next; chain; chain = next) {
next = chain->next;
free (chain);
}
iter.chain->next = NULL;
contour->tail = iter.chain;
}
}
void
_cairo_contour_reset (cairo_contour_t *contour)
{
_cairo_contour_fini (contour);
_cairo_contour_init (contour, contour->direction);
}
void
_cairo_contour_fini (cairo_contour_t *contour)
{
cairo_contour_chain_t *chain, *next;
for (chain = contour->chain.next; chain; chain = next) {
next = chain->next;
free (chain);
}
}
void
_cairo_debug_print_contour (FILE *file, cairo_contour_t *contour)
{
cairo_contour_chain_t *chain;
int num_points, size_points;
int i;
num_points = 0;
size_points = 0;
for (chain = &contour->chain; chain; chain = chain->next) {
num_points += chain->num_points;
size_points += chain->size_points;
}
fprintf (file, "contour: direction=%d, num_points=%d / %d\n",
contour->direction, num_points, size_points);
num_points = 0;
for (chain = &contour->chain; chain; chain = chain->next) {
for (i = 0; i < chain->num_points; i++) {
fprintf (file, " [%d] = (%f, %f)\n",
num_points++,
_cairo_fixed_to_double (chain->points[i].x),
_cairo_fixed_to_double (chain->points[i].y));
}
}
}
void
__cairo_contour_remove_last_chain (cairo_contour_t *contour)
{
cairo_contour_chain_t *chain;
if (contour->tail == &contour->chain)
return;
for (chain = &contour->chain; chain->next != contour->tail; chain = chain->next)
;
free (contour->tail);
contour->tail = chain;
chain->next = NULL;
}