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-rw-r--r--src/cairo-rectangular-scan-converter.c791
1 files changed, 791 insertions, 0 deletions
diff --git a/src/cairo-rectangular-scan-converter.c b/src/cairo-rectangular-scan-converter.c
new file mode 100644
index 000000000..e353b34e8
--- /dev/null
+++ b/src/cairo-rectangular-scan-converter.c
@@ -0,0 +1,791 @@
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2009 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
+ * 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.
+ *
+ * Contributor(s):
+ * Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairoint.h"
+
+#include "cairo-combsort-inline.h"
+#include "cairo-error-private.h"
+#include "cairo-freelist-private.h"
+#include "cairo-list-private.h"
+#include "cairo-spans-private.h"
+
+#include <setjmp.h>
+
+typedef struct _rectangle {
+ struct _rectangle *next, *prev;
+ cairo_fixed_t left, right;
+ cairo_fixed_t top, bottom;
+ int32_t top_y, bottom_y;
+ int dir;
+} rectangle_t;
+
+#define UNROLL3(x) x x x
+
+/* 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;
+
+ rectangle_t **elements;
+ rectangle_t *elements_embedded[1024];
+} pqueue_t;
+
+typedef struct {
+ rectangle_t **start;
+ pqueue_t stop;
+ rectangle_t head, tail;
+ rectangle_t *insert_cursor;
+ int32_t current_y;
+ int32_t xmin, xmax;
+
+ struct coverage {
+ struct cell {
+ struct cell *prev, *next;
+ int x, covered, uncovered;
+ } head, tail, *cursor;
+ unsigned int count;
+ cairo_freepool_t pool;
+ } coverage;
+
+ cairo_half_open_span_t spans_stack[CAIRO_STACK_ARRAY_LENGTH (cairo_half_open_span_t)];
+ cairo_half_open_span_t *spans;
+ unsigned int num_spans;
+ unsigned int size_spans;
+
+ jmp_buf jmpbuf;
+} sweep_line_t;
+
+static inline int
+rectangle_compare_start (const rectangle_t *a,
+ const rectangle_t *b)
+{
+ int cmp;
+
+ cmp = a->top_y - b->top_y;
+ if (cmp)
+ return cmp;
+
+ return a->left - b->left;
+}
+
+static inline int
+rectangle_compare_stop (const rectangle_t *a,
+ const rectangle_t *b)
+{
+ return a->bottom_y - b->bottom_y;
+}
+
+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_bool_t
+pqueue_grow (pqueue_t *pq)
+{
+ rectangle_t **new_elements;
+ pq->max_size *= 2;
+
+ if (pq->elements == pq->elements_embedded) {
+ new_elements = _cairo_malloc_ab (pq->max_size,
+ sizeof (rectangle_t *));
+ if (unlikely (new_elements == NULL))
+ return FALSE;
+
+ memcpy (new_elements, pq->elements_embedded,
+ sizeof (pq->elements_embedded));
+ } else {
+ new_elements = _cairo_realloc_ab (pq->elements,
+ pq->max_size,
+ sizeof (rectangle_t *));
+ if (unlikely (new_elements == NULL))
+ return FALSE;
+ }
+
+ pq->elements = new_elements;
+ return TRUE;
+}
+
+static inline void
+pqueue_push (sweep_line_t *sweep, rectangle_t *rectangle)
+{
+ rectangle_t **elements;
+ int i, parent;
+
+ if (unlikely (sweep->stop.size + 1 == sweep->stop.max_size)) {
+ if (unlikely (! pqueue_grow (&sweep->stop)))
+ longjmp (sweep->jmpbuf,
+ _cairo_error (CAIRO_STATUS_NO_MEMORY));
+ }
+
+ elements = sweep->stop.elements;
+ for (i = ++sweep->stop.size;
+ i != PQ_FIRST_ENTRY &&
+ rectangle_compare_stop (rectangle,
+ elements[parent = PQ_PARENT_INDEX (i)]) < 0;
+ i = parent)
+ {
+ elements[i] = elements[parent];
+ }
+
+ elements[i] = rectangle;
+}
+
+static inline void
+pqueue_pop (pqueue_t *pq)
+{
+ rectangle_t **elements = pq->elements;
+ 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 &&
+ rectangle_compare_stop (elements[child+1],
+ elements[child]) < 0)
+ {
+ child++;
+ }
+
+ if (rectangle_compare_stop (elements[child], tail) >= 0)
+ break;
+
+ elements[i] = elements[child];
+ }
+ elements[i] = tail;
+}
+
+static inline rectangle_t *
+peek_stop (sweep_line_t *sweep)
+{
+ return sweep->stop.elements[PQ_FIRST_ENTRY];
+}
+
+CAIRO_COMBSORT_DECLARE (rectangle_sort, rectangle_t *, rectangle_compare_start)
+
+static void
+sweep_line_init (sweep_line_t *sweep)
+{
+ sweep->head.left = INT_MIN;
+ sweep->head.next = &sweep->tail;
+ sweep->tail.left = INT_MAX;
+ sweep->tail.prev = &sweep->head;
+ sweep->insert_cursor = &sweep->tail;
+
+ _cairo_freepool_init (&sweep->coverage.pool, sizeof (struct cell));
+
+ sweep->spans = sweep->spans_stack;
+ sweep->size_spans = ARRAY_LENGTH (sweep->spans_stack);
+
+ sweep->coverage.head.prev = NULL;
+ sweep->coverage.head.x = INT_MIN;
+ sweep->coverage.tail.next = NULL;
+ sweep->coverage.tail.x = INT_MAX;
+
+ pqueue_init (&sweep->stop);
+}
+
+static void
+sweep_line_fini (sweep_line_t *sweep)
+{
+ _cairo_freepool_fini (&sweep->coverage.pool);
+ pqueue_fini (&sweep->stop);
+
+ if (sweep->spans != sweep->spans_stack)
+ free (sweep->spans);
+}
+
+static inline void
+add_cell (sweep_line_t *sweep, int x, int covered, int uncovered)
+{
+ struct cell *cell;
+
+ cell = sweep->coverage.cursor;
+ if (cell->x > x) {
+ do {
+ UNROLL3({
+ if (cell->prev->x < x)
+ break;
+ cell = cell->prev;
+ })
+ } while (TRUE);
+ } else {
+ if (cell->x == x)
+ goto found;
+
+ do {
+ UNROLL3({
+ cell = cell->next;
+ if (cell->x >= x)
+ break;
+ })
+ } while (TRUE);
+ }
+
+ if (x != cell->x) {
+ struct cell *c;
+
+ sweep->coverage.count++;
+
+ c = _cairo_freepool_alloc (&sweep->coverage.pool);
+ if (unlikely (c == NULL)) {
+ longjmp (sweep->jmpbuf,
+ _cairo_error (CAIRO_STATUS_NO_MEMORY));
+ }
+
+ cell->prev->next = c;
+ c->prev = cell->prev;
+ c->next = cell;
+ cell->prev = c;
+
+ c->x = x;
+ c->covered = 0;
+ c->uncovered = 0;
+
+ cell = c;
+ }
+
+found:
+ cell->covered += covered;
+ cell->uncovered += uncovered;
+ sweep->coverage.cursor = cell;
+}
+
+static inline void
+_active_edges_to_spans (sweep_line_t *sweep)
+{
+ int32_t y = sweep->current_y;
+ rectangle_t *rectangle;
+ int coverage, prev_coverage;
+ int prev_x;
+ struct cell *cell;
+
+ sweep->num_spans = 0;
+ if (sweep->head.next == &sweep->tail)
+ return;
+
+ sweep->coverage.head.next = &sweep->coverage.tail;
+ sweep->coverage.tail.prev = &sweep->coverage.head;
+ sweep->coverage.cursor = &sweep->coverage.tail;
+ sweep->coverage.count = 0;
+
+ /* XXX cell coverage only changes when a rectangle appears or
+ * disappears. Try only modifying coverage at such times.
+ */
+ for (rectangle = sweep->head.next;
+ rectangle != &sweep->tail;
+ rectangle = rectangle->next)
+ {
+ int height;
+ int frac, i;
+
+ if (y == rectangle->bottom_y) {
+ height = rectangle->bottom & CAIRO_FIXED_FRAC_MASK;
+ if (height == 0)
+ continue;
+ } else
+ height = CAIRO_FIXED_ONE;
+ if (y == rectangle->top_y)
+ height -= rectangle->top & CAIRO_FIXED_FRAC_MASK;
+ height *= rectangle->dir;
+
+ i = _cairo_fixed_integer_part (rectangle->left),
+ frac = _cairo_fixed_fractional_part (rectangle->left);
+ add_cell (sweep, i,
+ (CAIRO_FIXED_ONE-frac) * height,
+ frac * height);
+
+ i = _cairo_fixed_integer_part (rectangle->right),
+ frac = _cairo_fixed_fractional_part (rectangle->right);
+ add_cell (sweep, i,
+ -(CAIRO_FIXED_ONE-frac) * height,
+ -frac * height);
+ }
+
+ if (2*sweep->coverage.count >= sweep->size_spans) {
+ unsigned size;
+
+ size = sweep->size_spans;
+ while (size <= 2*sweep->coverage.count)
+ size <<= 1;
+
+ if (sweep->spans != sweep->spans_stack)
+ free (sweep->spans);
+
+ sweep->spans = _cairo_malloc_ab (size, sizeof (cairo_half_open_span_t));
+ if (unlikely (sweep->spans == NULL))
+ longjmp (sweep->jmpbuf, _cairo_error (CAIRO_STATUS_NO_MEMORY));
+
+ sweep->size_spans = size;
+ }
+
+ prev_coverage = coverage = 0;
+ prev_x = INT_MIN;
+ for (cell = sweep->coverage.head.next; cell != &sweep->coverage.tail; cell = cell->next) {
+ if (cell->x != prev_x && coverage != prev_coverage) {
+ int n = sweep->num_spans++;
+ int c = coverage >> (CAIRO_FIXED_FRAC_BITS * 2 - 8);
+ sweep->spans[n].x = prev_x;
+ sweep->spans[n].inverse = 0;
+ sweep->spans[n].coverage = c - (c >> 8);
+ prev_coverage = coverage;
+ }
+
+ coverage += cell->covered;
+ if (coverage != prev_coverage) {
+ int n = sweep->num_spans++;
+ int c = coverage >> (CAIRO_FIXED_FRAC_BITS * 2 - 8);
+ sweep->spans[n].x = cell->x;
+ sweep->spans[n].inverse = 0;
+ sweep->spans[n].coverage = c - (c >> 8);
+ prev_coverage = coverage;
+ }
+ coverage += cell->uncovered;
+ prev_x = cell->x + 1;
+ }
+ _cairo_freepool_reset (&sweep->coverage.pool);
+
+ if (sweep->num_spans) {
+ if (prev_x <= sweep->xmax) {
+ int n = sweep->num_spans++;
+ int c = coverage >> (CAIRO_FIXED_FRAC_BITS * 2 - 8);
+ sweep->spans[n].x = prev_x;
+ sweep->spans[n].inverse = 0;
+ sweep->spans[n].coverage = c - (c >> 8);
+ }
+
+ if (coverage && prev_x < sweep->xmax) {
+ int n = sweep->num_spans++;
+ sweep->spans[n].x = sweep->xmax;
+ sweep->spans[n].inverse = 1;
+ sweep->spans[n].coverage = 0;
+ }
+ }
+}
+
+static inline void
+sweep_line_delete (sweep_line_t *sweep,
+ rectangle_t *rectangle)
+{
+ if (sweep->insert_cursor == rectangle)
+ sweep->insert_cursor = rectangle->next;
+
+ rectangle->prev->next = rectangle->next;
+ rectangle->next->prev = rectangle->prev;
+
+ pqueue_pop (&sweep->stop);
+}
+
+static inline void
+sweep_line_insert (sweep_line_t *sweep,
+ rectangle_t *rectangle)
+{
+ rectangle_t *pos;
+
+ pos = sweep->insert_cursor;
+ if (pos->left != rectangle->left) {
+ if (pos->left > rectangle->left) {
+ do {
+ UNROLL3({
+ if (pos->prev->left < rectangle->left)
+ break;
+ pos = pos->prev;
+ })
+ } while (TRUE);
+ } else {
+ do {
+ UNROLL3({
+ pos = pos->next;
+ if (pos->left >= rectangle->left)
+ break;
+ });
+ } while (TRUE);
+ }
+ }
+
+ pos->prev->next = rectangle;
+ rectangle->prev = pos->prev;
+ rectangle->next = pos;
+ pos->prev = rectangle;
+ sweep->insert_cursor = rectangle;
+
+ pqueue_push (sweep, rectangle);
+}
+
+static void
+render_rows (sweep_line_t *sweep_line,
+ cairo_span_renderer_t *renderer,
+ int height)
+{
+ cairo_status_t status;
+
+ _active_edges_to_spans (sweep_line);
+
+ status = renderer->render_rows (renderer,
+ sweep_line->current_y, height,
+ sweep_line->spans,
+ sweep_line->num_spans);
+ if (unlikely (status))
+ longjmp (sweep_line->jmpbuf, status);
+}
+
+static cairo_status_t
+generate (cairo_rectangular_scan_converter_t *self,
+ cairo_span_renderer_t *renderer,
+ rectangle_t **rectangles)
+{
+ sweep_line_t sweep_line;
+ rectangle_t *start, *stop;
+ cairo_status_t status;
+
+ sweep_line_init (&sweep_line);
+ sweep_line.xmin = _cairo_fixed_integer_part (self->extents.p1.x);
+ sweep_line.xmax = _cairo_fixed_integer_part (self->extents.p2.x);
+ sweep_line.start = rectangles;
+ if ((status = setjmp (sweep_line.jmpbuf)))
+ goto out;
+
+ sweep_line.current_y = _cairo_fixed_integer_part (self->extents.p1.y);
+ start = *sweep_line.start++;
+ do {
+ if (start->top_y != sweep_line.current_y) {
+ render_rows (&sweep_line, renderer,
+ start->top_y - sweep_line.current_y);
+ sweep_line.current_y = start->top_y;
+ }
+
+ do {
+ sweep_line_insert (&sweep_line, start);
+ start = *sweep_line.start++;
+ if (start == NULL)
+ goto end;
+ if (start->top_y != sweep_line.current_y)
+ break;
+ } while (TRUE);
+
+ render_rows (&sweep_line, renderer, 1);
+
+ stop = peek_stop (&sweep_line);
+ while (stop->bottom_y == sweep_line.current_y) {
+ sweep_line_delete (&sweep_line, stop);
+ stop = peek_stop (&sweep_line);
+ if (stop == NULL)
+ break;
+ }
+
+ sweep_line.current_y++;
+
+ while (stop != NULL && stop->bottom_y < start->top_y) {
+ if (stop->bottom_y != sweep_line.current_y) {
+ render_rows (&sweep_line, renderer,
+ stop->bottom_y - sweep_line.current_y);
+ sweep_line.current_y = stop->bottom_y;
+ }
+
+ render_rows (&sweep_line, renderer, 1);
+
+ do {
+ sweep_line_delete (&sweep_line, stop);
+ stop = peek_stop (&sweep_line);
+ } while (stop != NULL && stop->bottom_y == sweep_line.current_y);
+
+ sweep_line.current_y++;
+ }
+ } while (TRUE);
+
+ end:
+ render_rows (&sweep_line, renderer, 1);
+
+ stop = peek_stop (&sweep_line);
+ while (stop->bottom_y == sweep_line.current_y) {
+ sweep_line_delete (&sweep_line, stop);
+ stop = peek_stop (&sweep_line);
+ if (stop == NULL)
+ goto out;
+ }
+
+ while (++sweep_line.current_y < _cairo_fixed_integer_part (self->extents.p2.y)) {
+ if (stop->bottom_y != sweep_line.current_y) {
+ render_rows (&sweep_line, renderer,
+ stop->bottom_y - sweep_line.current_y);
+ sweep_line.current_y = stop->bottom_y;
+ }
+
+ render_rows (&sweep_line, renderer, 1);
+
+ do {
+ sweep_line_delete (&sweep_line, stop);
+ stop = peek_stop (&sweep_line);
+ if (stop == NULL)
+ goto out;
+ } while (stop->bottom_y == sweep_line.current_y);
+
+ }
+
+ out:
+ sweep_line_fini (&sweep_line);
+
+ return status;
+}
+static void generate_row(cairo_span_renderer_t *renderer,
+ const rectangle_t *r,
+ int y, int h,
+ uint16_t coverage)
+{
+ cairo_half_open_span_t spans[4];
+ unsigned int num_spans = 0;
+ int x1 = _cairo_fixed_integer_part (r->left);
+ int x2 = _cairo_fixed_integer_part (r->right);
+ if (x2 > x1) {
+ if (! _cairo_fixed_is_integer (r->left)) {
+ spans[num_spans].x = x1;
+ spans[num_spans].coverage =
+ coverage * (256 - _cairo_fixed_fractional_part (r->left)) >> 8;
+ num_spans++;
+ x1++;
+ }
+
+ if (x2 > x1) {
+ spans[num_spans].x = x1;
+ spans[num_spans].coverage = coverage - (coverage >> 8);
+ num_spans++;
+ }
+
+ if (! _cairo_fixed_is_integer (r->right)) {
+ spans[num_spans].x = x2++;
+ spans[num_spans].coverage =
+ coverage * _cairo_fixed_fractional_part (r->right) >> 8;
+ num_spans++;
+ }
+ } else {
+ spans[num_spans].x = x2++;
+ spans[num_spans].coverage = coverage * (r->right - r->left) >> 8;
+ num_spans++;
+ }
+
+ spans[num_spans].x = x2;
+ spans[num_spans].coverage = 0;
+ num_spans++;
+
+ renderer->render_rows (renderer, y, h, spans, num_spans);
+}
+
+static cairo_status_t
+generate_box (cairo_rectangular_scan_converter_t *self,
+ cairo_span_renderer_t *renderer)
+{
+ const rectangle_t *r = self->chunks.base;
+ int y1 = _cairo_fixed_integer_part (r->top);
+ int y2 = _cairo_fixed_integer_part (r->bottom);
+ if (y2 > y1) {
+ if (! _cairo_fixed_is_integer (r->top)) {
+ generate_row(renderer, r, y1, 1,
+ 256 - _cairo_fixed_fractional_part (r->top));
+ y1++;
+ }
+
+ if (y2 > y1)
+ generate_row(renderer, r, y1, y2-y1, 256);
+
+ if (! _cairo_fixed_is_integer (r->bottom))
+ generate_row(renderer, r, y2, 1,
+ _cairo_fixed_fractional_part (r->bottom));
+ } else
+ generate_row(renderer, r, y1, 1, r->bottom - r->top);
+
+ return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_rectangular_scan_converter_generate (void *converter,
+ cairo_span_renderer_t *renderer)
+{
+ cairo_rectangular_scan_converter_t *self = converter;
+ rectangle_t *rectangles_stack[CAIRO_STACK_ARRAY_LENGTH (rectangle_t *)];
+ rectangle_t **rectangles;
+ struct _cairo_rectangular_scan_converter_chunk *chunk;
+ cairo_status_t status;
+ int i, j;
+
+ if (unlikely (self->num_rectangles == 0)) {
+ return renderer->render_rows (renderer,
+ _cairo_fixed_integer_part (self->extents.p1.y),
+ _cairo_fixed_integer_part (self->extents.p2.y - self->extents.p1.y),
+ NULL, 0);
+ }
+
+ if (self->num_rectangles == 1)
+ return generate_box (self, renderer);
+
+ rectangles = rectangles_stack;
+ if (unlikely (self->num_rectangles >= ARRAY_LENGTH (rectangles_stack))) {
+ rectangles = _cairo_malloc_ab (self->num_rectangles + 1,
+ sizeof (rectangle_t *));
+ if (unlikely (rectangles == NULL))
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+ }
+
+ j = 0;
+ for (chunk = &self->chunks; chunk != NULL; chunk = chunk->next) {
+ rectangle_t *rectangle;
+
+ rectangle = chunk->base;
+ for (i = 0; i < chunk->count; i++)
+ rectangles[j++] = &rectangle[i];
+ }
+ rectangle_sort (rectangles, j);
+ rectangles[j] = NULL;
+
+ status = generate (self, renderer, rectangles);
+
+ if (rectangles != rectangles_stack)
+ free (rectangles);
+
+ return status;
+}
+
+static rectangle_t *
+_allocate_rectangle (cairo_rectangular_scan_converter_t *self)
+{
+ rectangle_t *rectangle;
+ struct _cairo_rectangular_scan_converter_chunk *chunk;
+
+ chunk = self->tail;
+ if (chunk->count == chunk->size) {
+ int size;
+
+ size = chunk->size * 2;
+ chunk->next = _cairo_malloc_ab_plus_c (size,
+ sizeof (rectangle_t),
+ sizeof (struct _cairo_rectangular_scan_converter_chunk));
+
+ if (unlikely (chunk->next == NULL))
+ return NULL;
+
+ chunk = chunk->next;
+ chunk->next = NULL;
+ chunk->count = 0;
+ chunk->size = size;
+ chunk->base = chunk + 1;
+ self->tail = chunk;
+ }
+
+ rectangle = chunk->base;
+ return rectangle + chunk->count++;
+}
+
+cairo_status_t
+_cairo_rectangular_scan_converter_add_box (cairo_rectangular_scan_converter_t *self,
+ const cairo_box_t *box,
+ int dir)
+{
+ rectangle_t *rectangle;
+
+ rectangle = _allocate_rectangle (self);
+ if (unlikely (rectangle == NULL))
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+
+ rectangle->dir = dir;
+ rectangle->left = MAX (box->p1.x, self->extents.p1.x);
+ rectangle->right = MIN (box->p2.x, self->extents.p2.x);
+ if (unlikely (rectangle->right <= rectangle->left)) {
+ self->tail->count--;
+ return CAIRO_STATUS_SUCCESS;
+ }
+
+ rectangle->top = MAX (box->p1.y, self->extents.p1.y);
+ rectangle->top_y = _cairo_fixed_integer_floor (rectangle->top);
+ rectangle->bottom = MIN (box->p2.y, self->extents.p2.y);
+ rectangle->bottom_y = _cairo_fixed_integer_floor (rectangle->bottom);
+ if (likely (rectangle->bottom > rectangle->top))
+ self->num_rectangles++;
+ else
+ self->tail->count--;
+
+ return CAIRO_STATUS_SUCCESS;
+}
+
+static void
+_cairo_rectangular_scan_converter_destroy (void *converter)
+{
+ cairo_rectangular_scan_converter_t *self = converter;
+ struct _cairo_rectangular_scan_converter_chunk *chunk, *next;
+
+ for (chunk = self->chunks.next; chunk != NULL; chunk = next) {
+ next = chunk->next;
+ free (chunk);
+ }
+}
+
+void
+_cairo_rectangular_scan_converter_init (cairo_rectangular_scan_converter_t *self,
+ const cairo_rectangle_int_t *extents)
+{
+ self->base.destroy = _cairo_rectangular_scan_converter_destroy;
+ self->base.generate = _cairo_rectangular_scan_converter_generate;
+
+ _cairo_box_from_rectangle (&self->extents, extents);
+
+ self->chunks.base = self->buf;
+ self->chunks.next = NULL;
+ self->chunks.count = 0;
+ self->chunks.size = sizeof (self->buf) / sizeof (rectangle_t);
+ self->tail = &self->chunks;
+
+ self->num_rectangles = 0;
+}