[perf] Add pixman_region_init_rects and use in extract_region

Avoid O(N*N) loop in traps_extract_region by letting us hand pixman
an array of rects all at once.

perf/Makefile.am

@@ -36,7 +36,8 @@ cairo_perf_SOURCES =		\
 	world-map.c		\
 	world-map.h		\
 	zrusin.c		\
-	zrusin-another.h
+	zrusin-another.h	\
+	long-dashed-lines.c
 
 if CAIRO_HAS_WIN32_SURFACE
 cairo_perf_SOURCES += cairo-perf-win32.c

perf/cairo-perf.c

@@ -420,5 +420,6 @@ cairo_perf_case_t perf_cases[] = {
     { long_lines, 100, 100},
     { unaligned_clip, 100, 100},
     { rectangles, 512, 512},
+    { long_dashed_lines, 512, 512},
     { NULL }
 };

perf/cairo-perf.h

@@ -107,5 +107,6 @@ CAIRO_PERF_DECL (mosaic);
 CAIRO_PERF_DECL (long_lines);
 CAIRO_PERF_DECL (unaligned_clip);
 CAIRO_PERF_DECL (rectangles);
+CAIRO_PERF_DECL (long_dashed_lines);
 
 #endif

perf/long-dashed-lines.c

@@ -0,0 +1,67 @@
+/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
+/*
+ * Copyright © 2007 Mozilla Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Vladimir Vukicevic <vladimir@pobox.com>
+ */
+
+#include "cairo-perf.h"
+
+static cairo_perf_ticks_t
+do_long_dashed_lines (cairo_t *cr, int width, int height)
+{
+    double dash[2] = { 2.0, 2.0 };
+    int i;
+
+    cairo_save (cr);
+    cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+    cairo_paint (cr);
+
+    cairo_set_source_rgb (cr, 1.0, 0.0, 0.0);
+    cairo_set_dash (cr, dash, 2, 0.0);
+
+    cairo_perf_timer_start ();
+
+    cairo_new_path (cr);
+    cairo_set_line_width (cr, 1.0);
+
+    for (i = 0; i < height-1; i++) {
+	double y0 = (double) i + 0.5;
+	cairo_move_to (cr, 0.0, y0);
+	cairo_line_to (cr, width, y0);
+    }
+
+    cairo_stroke (cr);
+
+    cairo_perf_timer_stop ();
+
+    cairo_restore (cr);
+
+    return cairo_perf_timer_elapsed ();
+}
+
+void
+long_dashed_lines (cairo_perf_t *perf, cairo_t *cr, int width, int height)
+{
+    cairo_perf_run (perf, "long-dashed-lines", do_long_dashed_lines);
+}

pixman/src/pixman-remap.h

@@ -58,6 +58,7 @@
 #define pixman_region_copy _cairo_pixman_region_copy
 #define pixman_region_init _cairo_pixman_region_init
 #define pixman_region_init_rect _cairo_pixman_region_init_rect
+#define pixman_region_init_rects _cairo_pixman_region_init_rects
 #define pixman_region_init_with_extents _cairo_pixman_region_init_with_extents
 #define pixman_region_fini _cairo_pixman_region_fini
 #define pixman_region_empty _cairo_pixman_region_empty

pixman/src/pixman.h

@@ -141,6 +141,8 @@ pixman_region_init_rect(pixman_region16_t *region,
                         int x, int y, unsigned int width, unsigned int height);
 pixman_private void
 pixman_region_init_with_extents(pixman_region16_t *region, pixman_box16_t *extents);
+pixman_private pixman_region_status_t
+pixman_region_init_rects(pixman_region16_t *region, pixman_box16_t *boxes, int count);
 pixman_private void
 pixman_region_fini (pixman_region16_t *region);
 

pixman/src/pixregion.c

@@ -76,6 +76,8 @@ static pixman_region16_data_t  pixman_brokendata = {0, 0};
 
 static pixman_region_status_t
 pixman_break (pixman_region16_t *pReg);
+static pixman_region_status_t
+pixman_rect_alloc(pixman_region16_t * region, int n);
 
 /*
  * The functions in this file implement the Region abstraction used extensively
@@ -311,6 +313,33 @@ pixman_region_init_with_extents(pixman_region16_t *region, pixman_box16_t *exten
     region->data = NULL;
 }
 
+pixman_region_status_t
+pixman_region_init_rects(pixman_region16_t *region, pixman_box16_t *boxes, int count)
+{
+    int overlap;
+
+    if (count == 1) {
+	pixman_region_init_rect(region,
+				boxes[0].x1,
+				boxes[0].y1,
+				boxes[0].x2 - boxes[0].x1,
+				boxes[0].y2 - boxes[0].y1);
+	return PIXMAN_REGION_STATUS_SUCCESS;
+    }
+
+    pixman_region_init(region);
+    if (!pixman_rect_alloc(region, count))
+	return PIXMAN_REGION_STATUS_FAILURE;
+
+    /* Copy in the rects */
+    memcpy (PIXREGION_RECTS(region), boxes, sizeof(pixman_box16_t) * count);
+    region->data->numRects = count;
+
+    /* Validate */
+    region->extents.x1 = region->extents.x2 = 0;
+    return pixman_region_validate (region, &overlap);
+}
+
 void
 pixman_region_fini (pixman_region16_t *region)
 {

src/cairo-traps.c

@@ -597,7 +597,11 @@ cairo_int_status_t
 _cairo_traps_extract_region (cairo_traps_t     *traps,
 			     pixman_region16_t *region)
 {
-    int i;
+#define NUM_STATIC_BOXES 16
+    pixman_box16_t static_boxes[NUM_STATIC_BOXES];
+    pixman_box16_t *boxes;
+    int i, box_count;
+    pixman_region_status_t status;
 
     for (i = 0; i < traps->num_traps; i++)
 	if (!(traps->traps[i].left.p1.x == traps->traps[i].left.p2.x
@@ -609,26 +613,46 @@ _cairo_traps_extract_region (cairo_traps_t     *traps,
 	    return CAIRO_INT_STATUS_UNSUPPORTED;
 	}
 
-    pixman_region_init (region);
+    if (traps->num_traps <= NUM_STATIC_BOXES) {
+	boxes = static_boxes;
+    } else {
+	/*boxes = _cairo_malloc2 (traps->num_traps, sizeof(pixman_box16_t));*/
+	boxes = malloc (traps->num_traps * sizeof(pixman_box16_t));
+
+	if (boxes == NULL)
+	    return CAIRO_STATUS_NO_MEMORY;
+    }
+
+    box_count = 0;
 
     for (i = 0; i < traps->num_traps; i++) {
-	int x = _cairo_fixed_integer_part(traps->traps[i].left.p1.x);
-	int y = _cairo_fixed_integer_part(traps->traps[i].top);
-	int width = _cairo_fixed_integer_part(traps->traps[i].right.p1.x) - x;
-	int height = _cairo_fixed_integer_part(traps->traps[i].bottom) - y;
+	int x1 = _cairo_fixed_integer_part(traps->traps[i].left.p1.x);
+	int y1 = _cairo_fixed_integer_part(traps->traps[i].top);
+	int x2 = _cairo_fixed_integer_part(traps->traps[i].right.p1.x);
+	int y2 = _cairo_fixed_integer_part(traps->traps[i].bottom);
 
-	/* XXX: Sometimes we get degenerate trapezoids from the tesellator,
-	 * if we call pixman_region_union_rect(), it bizarrly fails on such
-	 * an empty rectangle, so skip them.
+	/* XXX: Sometimes we get degenerate trapezoids from the tesellator;
+	 * skip these.
 	 */
-	if (width == 0 || height == 0)
-	  continue;
+	if (x1 == x2 || y1 == y2)
+	    continue;
 
-	if (pixman_region_union_rect (region, region,
-				      x, y, width, height) != PIXMAN_REGION_STATUS_SUCCESS) {
-	    pixman_region_fini (region);
-	    return CAIRO_STATUS_NO_MEMORY;
-	}
+	boxes[box_count].x1 = (short) x1;
+	boxes[box_count].y1 = (short) y1;
+	boxes[box_count].x2 = (short) x2;
+	boxes[box_count].y2 = (short) y2;
+
+	box_count++;
+    }
+
+    status = pixman_region_init_rects (region, boxes, box_count);
+
+    if (boxes != static_boxes)
+	free (boxes);
+
+    if (status != PIXMAN_REGION_STATUS_SUCCESS) {
+	pixman_region_fini (region);
+	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
     return CAIRO_STATUS_SUCCESS;