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/*
* Copyright © 2004 Carl Worth
* Copyright © 2006 Red Hat, Inc.
* Copyright © 2009 Chris Wilson
*
* 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, Fifth Floor, Boston, MA 02110-1301 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 Carl Worth
*
* Contributor(s):
* Carl D. Worth <cworth@cworth.org>
* Chris Wilson <chris@chris-wilson.co.uk>
*/
/* Provide definitions for standalone compilation */
#include "cairoint.h"
#include "cairo-combsort-private.h"
#include "cairo-list-private.h"
typedef struct _cairo_bo_rectangle cairo_bo_rectangle_t;
typedef struct _cairo_bo_edge cairo_bo_edge_t;
/* A deferred trapezoid of an edge */
typedef struct _cairo_bo_trap {
cairo_bo_edge_t *right;
int32_t top;
} cairo_bo_trap_t;
struct _cairo_bo_edge {
int x;
int dir;
cairo_bo_trap_t deferred_trap;
cairo_list_t link;
};
struct _cairo_bo_rectangle {
cairo_bo_edge_t left, right;
int top, bottom;
};
/* the parent is always given by index/2 */
#define PQ_PARENT_INDEX(i) ((i) >> 1)
#define PQ_FIRST_ENTRY 1
/* left and right children are index * 2 and (index * 2) +1 respectively */
#define PQ_LEFT_CHILD_INDEX(i) ((i) << 1)
typedef struct _pqueue {
int size, max_size;
cairo_bo_rectangle_t **elements;
cairo_bo_rectangle_t *elements_embedded[1024];
} pqueue_t;
typedef struct _cairo_bo_sweep_line {
cairo_bo_rectangle_t **rectangles;
pqueue_t stop;
cairo_list_t sweep;
cairo_list_t *current_left, *current_right;
int32_t current_y;
int32_t last_y;
} cairo_bo_sweep_line_t;
#define DEBUG_TRAPS 0
#if DEBUG_TRAPS
static void
dump_traps (cairo_traps_t *traps, const char *filename)
{
FILE *file;
int n;
if (getenv ("CAIRO_DEBUG_TRAPS") == NULL)
return;
file = fopen (filename, "a");
if (file != NULL) {
for (n = 0; n < traps->num_traps; n++) {
fprintf (file, "%d %d L:(%d, %d), (%d, %d) R:(%d, %d), (%d, %d)\n",
traps->traps[n].top,
traps->traps[n].bottom,
traps->traps[n].left.p1.x,
traps->traps[n].left.p1.y,
traps->traps[n].left.p2.x,
traps->traps[n].left.p2.y,
traps->traps[n].right.p1.x,
traps->traps[n].right.p1.y,
traps->traps[n].right.p2.x,
traps->traps[n].right.p2.y);
}
fprintf (file, "\n");
fclose (file);
}
}
#else
#define dump_traps(traps, filename)
#endif
static inline int
cairo_bo_rectangle_compare_start (const cairo_bo_rectangle_t *a,
const cairo_bo_rectangle_t *b)
{
return a->top - b->top;
}
static inline int
_cairo_bo_rectangle_compare_stop (const cairo_bo_rectangle_t *a,
const cairo_bo_rectangle_t *b)
{
return a->bottom - b->bottom;
}
static inline void
_pqueue_init (pqueue_t *pq)
{
pq->max_size = ARRAY_LENGTH (pq->elements_embedded);
pq->size = 0;
pq->elements = pq->elements_embedded;
pq->elements[PQ_FIRST_ENTRY] = NULL;
}
static inline void
_pqueue_fini (pqueue_t *pq)
{
if (pq->elements != pq->elements_embedded)
free (pq->elements);
}
static cairo_status_t
_pqueue_grow (pqueue_t *pq)
{
cairo_bo_rectangle_t **new_elements;
pq->max_size *= 2;
if (pq->elements == pq->elements_embedded) {
new_elements = _cairo_malloc_ab (pq->max_size,
sizeof (cairo_bo_rectangle_t *));
if (unlikely (new_elements == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
memcpy (new_elements, pq->elements_embedded,
sizeof (pq->elements_embedded));
} else {
new_elements = _cairo_realloc_ab (pq->elements,
pq->max_size,
sizeof (cairo_bo_rectangle_t *));
if (unlikely (new_elements == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
}
pq->elements = new_elements;
return CAIRO_STATUS_SUCCESS;
}
static inline cairo_status_t
_pqueue_push (pqueue_t *pq, cairo_bo_rectangle_t *rectangle)
{
cairo_bo_rectangle_t **elements;
int i, parent;
if (unlikely (pq->size + 1 == pq->max_size)) {
cairo_status_t status;
status = _pqueue_grow (pq);
if (unlikely (status))
return status;
}
elements = pq->elements;
for (i = ++pq->size;
i != PQ_FIRST_ENTRY &&
_cairo_bo_rectangle_compare_stop (rectangle,
elements[parent = PQ_PARENT_INDEX (i)]) < 0;
i = parent)
{
elements[i] = elements[parent];
}
elements[i] = rectangle;
return CAIRO_STATUS_SUCCESS;
}
static inline void
_pqueue_pop (pqueue_t *pq)
{
cairo_bo_rectangle_t **elements = pq->elements;
cairo_bo_rectangle_t *tail;
int child, i;
tail = elements[pq->size--];
if (pq->size == 0) {
elements[PQ_FIRST_ENTRY] = NULL;
return;
}
for (i = PQ_FIRST_ENTRY;
(child = PQ_LEFT_CHILD_INDEX (i)) <= pq->size;
i = child)
{
if (child != pq->size &&
_cairo_bo_rectangle_compare_stop (elements[child+1],
elements[child]) < 0)
{
child++;
}
if (_cairo_bo_rectangle_compare_stop (elements[child], tail) >= 0)
break;
elements[i] = elements[child];
}
elements[i] = tail;
}
static inline cairo_bo_rectangle_t *
_cairo_bo_rectangle_pop_start (cairo_bo_sweep_line_t *sweep_line)
{
return *sweep_line->rectangles++;
}
static inline cairo_bo_rectangle_t *
_cairo_bo_rectangle_peek_stop (cairo_bo_sweep_line_t *sweep_line)
{
return sweep_line->stop.elements[PQ_FIRST_ENTRY];
}
CAIRO_COMBSORT_DECLARE (_cairo_bo_rectangle_sort,
cairo_bo_rectangle_t *,
cairo_bo_rectangle_compare_start)
static void
_cairo_bo_sweep_line_init (cairo_bo_sweep_line_t *sweep_line,
cairo_bo_rectangle_t **rectangles,
int num_rectangles)
{
_cairo_bo_rectangle_sort (rectangles, num_rectangles);
rectangles[num_rectangles] = NULL;
sweep_line->rectangles = rectangles;
cairo_list_init (&sweep_line->sweep);
sweep_line->current_left = &sweep_line->sweep;
sweep_line->current_right = &sweep_line->sweep;
sweep_line->current_y = INT32_MIN;
sweep_line->last_y = INT32_MIN;
_pqueue_init (&sweep_line->stop);
}
static void
_cairo_bo_sweep_line_fini (cairo_bo_sweep_line_t *sweep_line)
{
_pqueue_fini (&sweep_line->stop);
}
static inline cairo_bo_edge_t *
link_to_edge (cairo_list_t *elt)
{
return cairo_container_of (elt, cairo_bo_edge_t, link);
}
static cairo_status_t
_cairo_bo_edge_end_trap (cairo_bo_edge_t *left,
int32_t bot,
cairo_traps_t *traps)
{
cairo_bo_trap_t *trap = &left->deferred_trap;
/* Only emit (trivial) non-degenerate trapezoids with positive height. */
if (likely (trap->top < bot)) {
cairo_line_t _left = {
{ left->x, trap->top },
{ left->x, bot },
}, _right = {
{ trap->right->x, trap->top },
{ trap->right->x, bot },
};
_cairo_traps_add_trap (traps, trap->top, bot, &_left, &_right);
}
trap->right = NULL;
return _cairo_traps_status (traps);
}
/* Start a new trapezoid at the given top y coordinate, whose edges
* are `edge' and `edge->next'. If `edge' already has a trapezoid,
* then either add it to the traps in `traps', if the trapezoid's
* right edge differs from `edge->next', or do nothing if the new
* trapezoid would be a continuation of the existing one. */
static inline cairo_status_t
_cairo_bo_edge_start_or_continue_trap (cairo_bo_edge_t *left,
cairo_bo_edge_t *right,
int top,
cairo_traps_t *traps)
{
cairo_status_t status;
if (left->deferred_trap.right == right)
return CAIRO_STATUS_SUCCESS;
if (left->deferred_trap.right != NULL) {
if (right != NULL && left->deferred_trap.right->x == right->x) {
/* continuation on right, so just swap edges */
left->deferred_trap.right = right;
return CAIRO_STATUS_SUCCESS;
}
status = _cairo_bo_edge_end_trap (left, top, traps);
if (unlikely (status))
return status;
}
if (right != NULL && left->x != right->x) {
left->deferred_trap.top = top;
left->deferred_trap.right = right;
}
return CAIRO_STATUS_SUCCESS;
}
static inline cairo_status_t
_active_edges_to_traps (cairo_bo_sweep_line_t *sweep,
cairo_fill_rule_t fill_rule,
cairo_traps_t *traps)
{
int top = sweep->current_y;
cairo_list_t *pos = &sweep->sweep;
cairo_status_t status;
if (sweep->last_y == sweep->current_y)
return CAIRO_STATUS_SUCCESS;
if (fill_rule == CAIRO_FILL_RULE_WINDING) {
do {
cairo_bo_edge_t *left, *right;
int in_out;
pos = pos->next;
if (pos == &sweep->sweep)
break;
left = link_to_edge (pos);
in_out = left->dir;
/* Check if there is a co-linear edge with an existing trap */
if (left->deferred_trap.right == NULL) {
right = link_to_edge (pos->next);
while (unlikely (right->x == left->x)) {
if (right->deferred_trap.right != NULL) {
/* continuation on left */
left->deferred_trap = right->deferred_trap;
right->deferred_trap.right = NULL;
break;
}
right = link_to_edge (right->link.next);
}
}
/* Greedily search for the closing edge, so that we generate the
* maximal span width with the minimal number of trapezoids.
*/
right = link_to_edge (left->link.next);
do {
/* End all subsumed traps */
if (right->deferred_trap.right != NULL) {
status = _cairo_bo_edge_end_trap (right, top, traps);
if (unlikely (status))
return status;
}
in_out += right->dir;
if (in_out == 0) {
/* skip co-linear edges */
if (likely (right->link.next == &sweep->sweep ||
right->x != link_to_edge (right->link.next)->x))
{
break;
}
}
right = link_to_edge (right->link.next);
} while (TRUE);
status = _cairo_bo_edge_start_or_continue_trap (left, right,
top, traps);
if (unlikely (status))
return status;
pos = &right->link;
} while (TRUE);
} else {
cairo_bo_edge_t *left, *right;
do {
int in_out = 0;
pos = pos->next;
if (pos == &sweep->sweep)
break;
left = link_to_edge (pos);
pos = pos->next;
do {
right = link_to_edge (pos);
if (right->deferred_trap.right != NULL) {
status = _cairo_bo_edge_end_trap (right, top, traps);
if (unlikely (status))
return status;
}
if ((in_out++ & 1) == 0) {
cairo_list_t *next;
cairo_bool_t skip = FALSE;
/* skip co-linear edges */
next = pos->next;
if (next != &sweep->sweep)
skip = right->x == link_to_edge (next)->x;
if (! skip)
break;
}
pos = pos->next;
} while (TRUE);
right = pos == &sweep->sweep ? NULL : link_to_edge (pos);
status = _cairo_bo_edge_start_or_continue_trap (left, right,
top, traps);
if (unlikely (status))
return status;
} while (right != NULL);
}
sweep->last_y = sweep->current_y;
return CAIRO_STATUS_SUCCESS;
}
static inline cairo_status_t
_cairo_bo_sweep_line_delete_edge (cairo_bo_sweep_line_t *sweep_line,
cairo_bo_edge_t *edge,
cairo_traps_t *traps)
{
if (edge->deferred_trap.right != NULL) {
cairo_bo_edge_t *next = link_to_edge (edge->link.next);
if (&next->link != &sweep_line->sweep && next->x == edge->x) {
next->deferred_trap = edge->deferred_trap;
} else {
cairo_status_t status;
status = _cairo_bo_edge_end_trap (edge,
sweep_line->current_y,
traps);
if (unlikely (status))
return status;
}
}
if (sweep_line->current_left == &edge->link)
sweep_line->current_left = edge->link.prev;
if (sweep_line->current_right == &edge->link)
sweep_line->current_right = edge->link.next;
cairo_list_del (&edge->link);
return CAIRO_STATUS_SUCCESS;
}
static inline cairo_status_t
_cairo_bo_sweep_line_delete (cairo_bo_sweep_line_t *sweep_line,
cairo_bo_rectangle_t *rectangle,
cairo_fill_rule_t fill_rule,
cairo_traps_t *traps)
{
cairo_status_t status;
if (rectangle->bottom != sweep_line->current_y) {
status = _active_edges_to_traps (sweep_line, fill_rule, traps);
if (unlikely (status))
return status;
sweep_line->current_y = rectangle->bottom;
}
status = _cairo_bo_sweep_line_delete_edge (sweep_line,
&rectangle->left,
traps);
if (unlikely (status))
return status;
status = _cairo_bo_sweep_line_delete_edge (sweep_line,
&rectangle->right,
traps);
if (unlikely (status))
return status;
_pqueue_pop (&sweep_line->stop);
return CAIRO_STATUS_SUCCESS;
}
static cairo_bool_t
validate_sweep_line (cairo_bo_sweep_line_t *sweep_line)
{
int32_t last_x = INT32_MIN;
cairo_bo_edge_t *edge;
cairo_list_foreach_entry (edge, cairo_bo_edge_t, &sweep_line->sweep, link) {
if (edge->x < last_x)
return FALSE;
last_x = edge->x;
}
return TRUE;
}
static inline cairo_status_t
_cairo_bo_sweep_line_insert (cairo_bo_sweep_line_t *sweep_line,
cairo_bo_rectangle_t *rectangle,
cairo_fill_rule_t fill_rule,
cairo_traps_t *traps)
{
cairo_list_t *pos;
cairo_status_t status;
if (rectangle->top != sweep_line->current_y) {
cairo_bo_rectangle_t *stop;
stop = _cairo_bo_rectangle_peek_stop (sweep_line);
while (stop != NULL && stop->bottom < rectangle->top) {
status = _cairo_bo_sweep_line_delete (sweep_line, stop,
fill_rule, traps);
if (unlikely (status))
return status;
stop = _cairo_bo_rectangle_peek_stop (sweep_line);
}
status = _active_edges_to_traps (sweep_line, fill_rule, traps);
if (unlikely (status))
return status;
sweep_line->current_y = rectangle->top;
}
/* right edge */
pos = sweep_line->current_right;
if (pos == &sweep_line->sweep)
pos = sweep_line->sweep.prev;
if (pos != &sweep_line->sweep) {
int cmp;
cmp = link_to_edge (pos)->x - rectangle->right.x;
if (cmp < 0) {
while (pos->next != &sweep_line->sweep &&
link_to_edge (pos->next)->x - rectangle->right.x < 0)
{
pos = pos->next;
}
} else if (cmp > 0) {
do {
pos = pos->prev;
} while (pos != &sweep_line->sweep &&
link_to_edge (pos)->x - rectangle->right.x > 0);
}
cairo_list_add (&rectangle->right.link, pos);
} else {
cairo_list_add_tail (&rectangle->right.link, pos);
}
sweep_line->current_right = &rectangle->right.link;
assert (validate_sweep_line (sweep_line));
/* left edge */
pos = sweep_line->current_left;
if (pos == &sweep_line->sweep)
pos = sweep_line->sweep.next;
if (pos != &sweep_line->sweep) {
int cmp;
if (link_to_edge (pos)->x >= rectangle->right.x) {
pos = rectangle->right.link.prev;
if (pos == &sweep_line->sweep)
goto left_done;
}
cmp = link_to_edge (pos)->x - rectangle->left.x;
if (cmp < 0) {
while (pos->next != &sweep_line->sweep &&
link_to_edge (pos->next)->x - rectangle->left.x < 0)
{
pos = pos->next;
}
} else if (cmp > 0) {
do {
pos = pos->prev;
} while (pos != &sweep_line->sweep &&
link_to_edge (pos)->x - rectangle->left.x > 0);
}
}
left_done:
cairo_list_add (&rectangle->left.link, pos);
sweep_line->current_left = &rectangle->left.link;
assert (validate_sweep_line (sweep_line));
return _pqueue_push (&sweep_line->stop, rectangle);
}
static cairo_status_t
_cairo_bentley_ottmann_tessellate_rectangular (cairo_bo_rectangle_t **rectangles,
int num_rectangles,
cairo_fill_rule_t fill_rule,
cairo_traps_t *traps)
{
cairo_bo_sweep_line_t sweep_line;
cairo_bo_rectangle_t *rectangle;
cairo_status_t status = CAIRO_STATUS_SUCCESS;
_cairo_bo_sweep_line_init (&sweep_line, rectangles, num_rectangles);
while ((rectangle = _cairo_bo_rectangle_pop_start (&sweep_line)) != NULL) {
status = _cairo_bo_sweep_line_insert (&sweep_line, rectangle,
fill_rule, traps);
if (unlikely (status))
goto BAIL;
}
while ((rectangle = _cairo_bo_rectangle_peek_stop (&sweep_line)) != NULL) {
status = _cairo_bo_sweep_line_delete (&sweep_line, rectangle,
fill_rule, traps);
if (unlikely (status))
goto BAIL;
}
BAIL:
_cairo_bo_sweep_line_fini (&sweep_line);
return status;
}
cairo_status_t
_cairo_bentley_ottmann_tessellate_rectangular_traps (cairo_traps_t *traps,
cairo_fill_rule_t fill_rule)
{
cairo_bo_rectangle_t stack_rectangles[CAIRO_STACK_ARRAY_LENGTH (cairo_bo_rectangle_t)];
cairo_bo_rectangle_t *rectangles;
cairo_bo_rectangle_t *stack_rectangles_ptrs[ARRAY_LENGTH (stack_rectangles) + 1];
cairo_bo_rectangle_t **rectangles_ptrs;
cairo_status_t status;
int i;
if (unlikely (traps->num_traps == 0))
return CAIRO_STATUS_SUCCESS;
assert (traps->is_rectangular);
dump_traps (traps, "bo-rects-traps-in.txt");
rectangles = stack_rectangles;
rectangles_ptrs = stack_rectangles_ptrs;
if (traps->num_traps > ARRAY_LENGTH (stack_rectangles)) {
rectangles = _cairo_malloc_ab_plus_c (traps->num_traps,
sizeof (cairo_bo_rectangle_t) +
sizeof (cairo_bo_rectangle_t *),
sizeof (cairo_bo_rectangle_t *));
if (unlikely (rectangles == NULL))
return _cairo_error (CAIRO_STATUS_NO_MEMORY);
rectangles_ptrs = (cairo_bo_rectangle_t **) (rectangles + traps->num_traps);
}
for (i = 0; i < traps->num_traps; i++) {
if (traps->traps[i].left.p1.x < traps->traps[i].right.p1.x) {
rectangles[i].left.x = traps->traps[i].left.p1.x;
rectangles[i].left.dir = 1;
rectangles[i].right.x = traps->traps[i].right.p1.x;
rectangles[i].right.dir = -1;
} else {
rectangles[i].right.x = traps->traps[i].left.p1.x;
rectangles[i].right.dir = 1;
rectangles[i].left.x = traps->traps[i].right.p1.x;
rectangles[i].left.dir = -1;
}
rectangles[i].left.deferred_trap.right = NULL;
cairo_list_init (&rectangles[i].left.link);
rectangles[i].right.deferred_trap.right = NULL;
cairo_list_init (&rectangles[i].right.link);
rectangles[i].top = traps->traps[i].top;
rectangles[i].bottom = traps->traps[i].bottom;
rectangles_ptrs[i] = &rectangles[i];
}
_cairo_traps_clear (traps);
status = _cairo_bentley_ottmann_tessellate_rectangular (rectangles_ptrs, i,
fill_rule,
traps);
traps->is_rectilinear = TRUE;
traps->is_rectangular = TRUE;
if (rectangles != stack_rectangles)
free (rectangles);
dump_traps (traps, "bo-rects-traps-out.txt");
return status;
}