forked from KolibriOS/kolibrios
457 lines
11 KiB
C
457 lines
11 KiB
C
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/*
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* Copyright © 2004 Carl Worth
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* Copyright © 2006 Red Hat, Inc.
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* Copyright © 2008 Chris Wilson
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* Copyright © 2011 Intel Corporation
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*
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* This library is free software; you can redistribute it and/or
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* modify it either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is Carl Worth
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*
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* Contributor(s):
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* Carl D. Worth <cworth@cworth.org>
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* Chris Wilson <chris@chris-wilson.co.uk>
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*/
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typedef unsigned long long uint64_t;
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#include "cairoint.h"
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#include "cairo-error-private.h"
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#include "cairo-freelist-private.h"
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#include "cairo-combsort-inline.h"
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#include "cairo-contour-inline.h"
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#include "cairo-contour-private.h"
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void
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_cairo_contour_init (cairo_contour_t *contour,
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int direction)
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{
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contour->direction = direction;
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contour->chain.points = contour->embedded_points;
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contour->chain.next = NULL;
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contour->chain.num_points = 0;
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contour->chain.size_points = ARRAY_LENGTH (contour->embedded_points);
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contour->tail = &contour->chain;
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}
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cairo_int_status_t
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__cairo_contour_add_point (cairo_contour_t *contour,
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const cairo_point_t *point)
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{
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cairo_contour_chain_t *tail = contour->tail;
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cairo_contour_chain_t *next;
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assert (tail->next == NULL);
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next = _cairo_malloc_ab_plus_c (tail->size_points*2,
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sizeof (cairo_point_t),
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sizeof (cairo_contour_chain_t));
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if (unlikely (next == NULL))
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return _cairo_error (CAIRO_STATUS_NO_MEMORY);
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next->size_points = tail->size_points*2;
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next->num_points = 1;
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next->points = (cairo_point_t *)(next+1);
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next->next = NULL;
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tail->next = next;
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contour->tail = next;
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next->points[0] = *point;
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return CAIRO_INT_STATUS_SUCCESS;
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}
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static void
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first_inc (cairo_contour_t *contour,
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cairo_point_t **p,
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cairo_contour_chain_t **chain)
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{
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if (*p == (*chain)->points + (*chain)->num_points) {
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assert ((*chain)->next);
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*chain = (*chain)->next;
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*p = &(*chain)->points[0];
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} else
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++*p;
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}
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static void
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last_dec (cairo_contour_t *contour,
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cairo_point_t **p,
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cairo_contour_chain_t **chain)
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{
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if (*p == (*chain)->points) {
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cairo_contour_chain_t *prev;
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assert (*chain != &contour->chain);
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for (prev = &contour->chain; prev->next != *chain; prev = prev->next)
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;
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*chain = prev;
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*p = &(*chain)->points[(*chain)->num_points-1];
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} else
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--*p;
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}
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void
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_cairo_contour_reverse (cairo_contour_t *contour)
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{
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cairo_contour_chain_t *first_chain, *last_chain;
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cairo_point_t *first, *last;
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contour->direction = -contour->direction;
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if (contour->chain.num_points <= 1)
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return;
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first_chain = &contour->chain;
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last_chain = contour->tail;
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first = &first_chain->points[0];
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last = &last_chain->points[last_chain->num_points-1];
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while (first != last) {
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cairo_point_t p;
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p = *first;
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*first = *last;
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*last = p;
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first_inc (contour, &first, &first_chain);
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last_dec (contour, &last, &last_chain);
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}
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}
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cairo_int_status_t
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_cairo_contour_add (cairo_contour_t *dst,
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const cairo_contour_t *src)
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{
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const cairo_contour_chain_t *chain;
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cairo_int_status_t status;
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int i;
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for (chain = &src->chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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status = _cairo_contour_add_point (dst, &chain->points[i]);
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if (unlikely (status))
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return status;
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}
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}
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return CAIRO_INT_STATUS_SUCCESS;
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}
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static inline cairo_bool_t
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iter_next (cairo_contour_iter_t *iter)
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{
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if (iter->point == &iter->chain->points[iter->chain->size_points-1]) {
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iter->chain = iter->chain->next;
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if (iter->chain == NULL)
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return FALSE;
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iter->point = &iter->chain->points[0];
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return TRUE;
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} else {
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iter->point++;
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return TRUE;
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}
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}
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static cairo_bool_t
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iter_equal (const cairo_contour_iter_t *i1,
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const cairo_contour_iter_t *i2)
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{
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return i1->chain == i2->chain && i1->point == i2->point;
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}
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static void
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iter_init (cairo_contour_iter_t *iter, cairo_contour_t *contour)
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{
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iter->chain = &contour->chain;
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iter->point = &contour->chain.points[0];
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}
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static void
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iter_init_last (cairo_contour_iter_t *iter, cairo_contour_t *contour)
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{
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iter->chain = contour->tail;
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iter->point = &contour->tail->points[contour->tail->num_points-1];
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}
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static const cairo_contour_chain_t *prev_const_chain(const cairo_contour_t *contour,
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const cairo_contour_chain_t *chain)
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{
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const cairo_contour_chain_t *prev;
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if (chain == &contour->chain)
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return NULL;
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for (prev = &contour->chain; prev->next != chain; prev = prev->next)
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;
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return prev;
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}
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cairo_int_status_t
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_cairo_contour_add_reversed (cairo_contour_t *dst,
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const cairo_contour_t *src)
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{
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const cairo_contour_chain_t *last;
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cairo_int_status_t status;
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int i;
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if (src->chain.num_points == 0)
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return CAIRO_INT_STATUS_SUCCESS;
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for (last = src->tail; last; last = prev_const_chain (src, last)) {
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for (i = last->num_points-1; i >= 0; i--) {
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status = _cairo_contour_add_point (dst, &last->points[i]);
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if (unlikely (status))
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return status;
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}
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}
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return CAIRO_INT_STATUS_SUCCESS;
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}
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static cairo_uint64_t
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point_distance_sq (const cairo_point_t *p1,
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const cairo_point_t *p2)
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{
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int32_t dx = p1->x - p2->x;
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int32_t dy = p1->y - p2->y;
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return _cairo_int64_add(_cairo_int32x32_64_mul (dx, dx), _cairo_int32x32_64_mul (dy, dy));
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}
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#define DELETED(p) ((p)->x == INT_MIN && (p)->y == INT_MAX)
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#define MARK_DELETED(p) ((p)->x = INT_MIN, (p)->y = INT_MAX)
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static cairo_bool_t
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_cairo_contour_simplify_chain (cairo_contour_t *contour, const double tolerance,
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const cairo_contour_iter_t *first,
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const cairo_contour_iter_t *last)
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{
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cairo_contour_iter_t iter, furthest;
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uint64_t max_error;
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int x0, y0;
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int nx, ny;
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int count;
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iter = *first;
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iter_next (&iter);
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if (iter_equal (&iter, last))
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return FALSE;
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x0 = first->point->x;
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y0 = first->point->y;
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nx = last->point->y - y0;
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ny = x0 - last->point->x;
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count = 0;
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max_error = 0;
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do {
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cairo_point_t *p = iter.point;
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if (! DELETED(p)) {
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uint64_t d = (uint64_t)nx * (x0 - p->x) + (uint64_t)ny * (y0 - p->y);
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if (d * d > max_error) {
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max_error = d * d;
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furthest = iter;
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}
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count++;
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}
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iter_next (&iter);
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} while (! iter_equal (&iter, last));
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if (count == 0)
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return FALSE;
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if (max_error > tolerance * ((uint64_t)nx * nx + (uint64_t)ny * ny)) {
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cairo_bool_t simplified;
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simplified = FALSE;
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simplified |= _cairo_contour_simplify_chain (contour, tolerance,
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first, &furthest);
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simplified |= _cairo_contour_simplify_chain (contour, tolerance,
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&furthest, last);
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return simplified;
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} else {
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iter = *first;
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iter_next (&iter);
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do {
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MARK_DELETED (iter.point);
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iter_next (&iter);
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} while (! iter_equal (&iter, last));
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return TRUE;
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}
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}
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void
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_cairo_contour_simplify (cairo_contour_t *contour, double tolerance)
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{
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cairo_contour_chain_t *chain;
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cairo_point_t *last = NULL;
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cairo_contour_iter_t iter, furthest;
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cairo_bool_t simplified;
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uint64_t max = 0;
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int i;
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if (contour->chain.num_points <= 2)
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return;
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tolerance = tolerance * CAIRO_FIXED_ONE;
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tolerance *= tolerance;
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/* stage 1: vertex reduction */
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for (chain = &contour->chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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if (last == NULL ||
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_cairo_uint64_to_double(point_distance_sq (last, &chain->points[i])) > tolerance) {
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last = &chain->points[i];
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} else {
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MARK_DELETED (&chain->points[i]);
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}
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}
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}
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/* stage2: polygon simplification using Douglas-Peucker */
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simplified = FALSE;
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do {
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last = &contour->chain.points[0];
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iter_init (&furthest, contour);
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max = 0;
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for (chain = &contour->chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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uint64_t d;
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if (DELETED (&chain->points[i]))
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continue;
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d = point_distance_sq (last, &chain->points[i]);
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if (d > max) {
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furthest.chain = chain;
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furthest.point = &chain->points[i];
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max = d;
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}
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}
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}
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assert (max);
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simplified = FALSE;
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iter_init (&iter, contour);
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simplified |= _cairo_contour_simplify_chain (contour, tolerance,
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&iter, &furthest);
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iter_init_last (&iter, contour);
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if (! iter_equal (&furthest, &iter))
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simplified |= _cairo_contour_simplify_chain (contour, tolerance,
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&furthest, &iter);
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} while (simplified);
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iter_init (&iter, contour);
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for (chain = &contour->chain; chain; chain = chain->next) {
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int num_points = chain->num_points;
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chain->num_points = 0;
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for (i = 0; i < num_points; i++) {
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if (! DELETED(&chain->points[i])) {
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if (iter.point != &chain->points[i])
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*iter.point = chain->points[i];
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iter.chain->num_points++;
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iter_next (&iter);
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}
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}
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}
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if (iter.chain) {
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cairo_contour_chain_t *next;
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for (chain = iter.chain->next; chain; chain = next) {
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next = chain->next;
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free (chain);
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}
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iter.chain->next = NULL;
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contour->tail = iter.chain;
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}
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}
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void
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_cairo_contour_reset (cairo_contour_t *contour)
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{
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_cairo_contour_fini (contour);
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_cairo_contour_init (contour, contour->direction);
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}
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void
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_cairo_contour_fini (cairo_contour_t *contour)
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{
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cairo_contour_chain_t *chain, *next;
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for (chain = contour->chain.next; chain; chain = next) {
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next = chain->next;
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free (chain);
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}
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}
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void
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_cairo_debug_print_contour (FILE *file, cairo_contour_t *contour)
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{
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cairo_contour_chain_t *chain;
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int num_points, size_points;
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int i;
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num_points = 0;
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size_points = 0;
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for (chain = &contour->chain; chain; chain = chain->next) {
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num_points += chain->num_points;
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size_points += chain->size_points;
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}
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fprintf (file, "contour: direction=%d, num_points=%d / %d\n",
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contour->direction, num_points, size_points);
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num_points = 0;
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for (chain = &contour->chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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fprintf (file, " [%d] = (%f, %f)\n",
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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;
|
||
|
}
|