Merge branch 'master' into gammagamma

Conflicts:
	pixman/pixman-transformed.c

7 files changed, 516 insertions, 34 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index 33e2200d..cccb6f80 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,19 +1,35 @@
-if HAVE_GTK
+TEST_LDADD = $(top_builddir)/pixman/libpixman-1.la
+INCLUDES = -I$(top_srcdir)/pixman -I$(top_builddir)/pixman 
+
 TESTPROGRAMS =			\
+	region-test		\
+	scaling-test		\
+	fetch-test
+
+fetch_test_LDADD = $(TEST_LDADD)
+region_test_LDADD = $(TEST_LDADD)
+scaling_test_LDADD = $(TEST_LDADD)
+
+# GTK using test programs
+
+if HAVE_GTK
+
+GTK_LDADD = $(TEST_LDADD) $(GTK_LIBS)
+
+TESTPROGRAMS +=			\
 	clip-test		\
 	composite-test		\
 	gradient-test		\
-	region-test		\
-	fetch-test
+	trap-test
 
 noinst_PROGRAMS = $(TESTPROGRAMS)
 
-INCLUDES = -I$(top_srcdir)/pixman -I$(top_builddir)/pixman $(GTK_CFLAGS)
+INCLUDES += $(GTK_CFLAGS)
 
-composite_test_LDADD =	$(top_builddir)/pixman/libpixman-1.la $(GTK_LIBS)
-gradient_test_LDADD = $(top_builddir)/pixman/libpixman-1.la $(GTK_LIBS)
-fetch_test_LDADD = $(top_builddir)/pixman/libpixman-1.la
-region_test_LDADD = $(top_builddir)/pixman/libpixman-1.la
-clip_test_LDADD = $(top_builddir)/pixman/libpixman-1.la $(GTK_LIBS)
+composite_test_LDADD = $(GTK_LDADD)
+gradient_test_LDADD = $(GTK_LDADD)
+clip_test_LDADD = $(GTK_LDADD)
+trap_test_LDADD = $(GTK_LDADD)
 
 endif
+
diff --git a/test/clip-test.c b/test/clip-test.c
index 457e97a2..4995083c 100644
--- a/test/clip-test.c
+++ b/test/clip-test.c
@@ -20,14 +20,27 @@ pixbuf_from_argb32 (uint32_t *bits,
 	for (w = 0; w < width; ++w)
 	{
 	    uint32_t argb = bits[h * stride + w];
-	    guint32 abgr;
-	    
-	    abgr = (argb & 0xff000000) |
-		(argb & 0xff) << 16 |
-		(argb & 0x00ff00) |
-		(argb & 0xff0000) >> 16;
-	    
-	    p_bits[h * (p_stride / 4) + w] = abgr;
+	    guint r, g, b, a;
+	    char *pb = p_bits;
+
+	    pb += h * p_stride + w * 4;
+
+	    r = (argb & 0x00ff0000) >> 16;
+	    g = (argb & 0x0000ff00) >> 8;
+	    b = (argb & 0x000000ff) >> 0;
+	    a = (argb & 0xff000000) >> 24;
+
+	    if (a)
+	    {
+		r = (r * 255) / a;
+		g = (g * 255) / a;
+		b = (b * 255) / a;
+	    }
+
+	    pb[0] = r;
+	    pb[1] = g;
+	    pb[2] = b;
+	    pb[3] = a;
 	}
     }
     
diff --git a/test/composite-test.c b/test/composite-test.c
index d6596f49..388c8e64 100644
--- a/test/composite-test.c
+++ b/test/composite-test.c
@@ -1,10 +1,9 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include "pixman.h"
-
 #include <gtk/gtk.h>
 
-static GdkPixbuf *
+GdkPixbuf *
 pixbuf_from_argb32 (uint32_t *bits,
 		    int width,
 		    int height,
@@ -15,20 +14,36 @@ pixbuf_from_argb32 (uint32_t *bits,
     int p_stride = gdk_pixbuf_get_rowstride (pixbuf);
     guint32 *p_bits = (guint32 *)gdk_pixbuf_get_pixels (pixbuf);
     int w, h;
-
+    
     for (h = 0; h < height; ++h)
     {
 	for (w = 0; w < width; ++w)
 	{
 	    uint32_t argb = bits[h * stride + w];
-	    guint32 rgba;
-
-	    rgba = (argb << 8) | (argb >> 24);
-
-	    p_bits[h * (p_stride / 4) + w] = rgba;
+	    guint r, g, b, a;
+	    char *pb = p_bits;
+
+	    pb += h * p_stride + w * 4;
+
+	    r = (argb & 0x00ff0000) >> 16;
+	    g = (argb & 0x0000ff00) >> 8;
+	    b = (argb & 0x000000ff) >> 0;
+	    a = (argb & 0xff000000) >> 24;
+
+	    if (a)
+	    {
+		r = (r * 255) / a;
+		g = (g * 255) / a;
+		b = (b * 255) / a;
+	    }
+
+	    pb[0] = r;
+	    pb[1] = g;
+	    pb[2] = b;
+	    pb[3] = a;
 	}
     }
-
+    
     return pixbuf;
 }
 
diff --git a/test/gradient-test.c b/test/gradient-test.c
index 8a99ff0e..806256bb 100644
--- a/test/gradient-test.c
+++ b/test/gradient-test.c
@@ -20,14 +20,27 @@ pixbuf_from_argb32 (uint32_t *bits,
 	for (w = 0; w < width; ++w)
 	{
 	    uint32_t argb = bits[h * stride + w];
-	    guint32 abgr;
-	    
-	    abgr = (argb & 0xff000000) |
-		(argb & 0xff) << 16 |
-		(argb & 0x00ff00) |
-		(argb & 0xff0000) >> 16;
-	    
-	    p_bits[h * (p_stride / 4) + w] = abgr;
+	    guint r, g, b, a;
+	    char *pb = p_bits;
+
+	    pb += h * p_stride + w * 4;
+
+	    r = (argb & 0x00ff0000) >> 16;
+	    g = (argb & 0x0000ff00) >> 8;
+	    b = (argb & 0x000000ff) >> 0;
+	    a = (argb & 0xff000000) >> 24;
+
+	    if (a)
+	    {
+		r = (r * 255) / a;
+		g = (g * 255) / a;
+		b = (b * 255) / a;
+	    }
+
+	    pb[0] = r;
+	    pb[1] = g;
+	    pb[2] = b;
+	    pb[3] = a;
 	}
     }
     
diff --git a/test/scaling-test-bisect.rb b/test/scaling-test-bisect.rb
new file mode 100644
index 00000000..2e4aff30
--- /dev/null
+++ b/test/scaling-test-bisect.rb
@@ -0,0 +1,38 @@
+#!/usr/bin/env ruby
+
+if not ARGV[0] or not ARGV[1] then
+    printf("Please provide two 'scaling-test' static binaries in the command line.\n\n")
+    printf("The first should be linked with the correct reference pixman library.\n")
+    printf("The second binrary should be linked with the pixman library to be tested.\n")
+    exit(0)
+end
+
+$MAX = 10000
+$MIN = 1
+$AVG = 0
+
+if `#{ARGV[0]} #{$MAX} 2>/dev/null` == `#{ARGV[1]} #{$MAX} 2>/dev/null` then
+    printf("test ok\n")
+    exit(0)
+end
+
+printf("test failed, bisecting...\n")
+
+while $MAX != $MIN + 1 do
+    $AVG = (($MIN + $MAX) / 2).to_i
+    res1 = `#{ARGV[0]} #{$AVG} 2>/dev/null`
+    res2 = `#{ARGV[1]} #{$AVG} 2>/dev/null`
+    if res1 != res2 then
+        $MAX = $AVG
+    else
+        $MIN = $AVG
+    end
+end
+
+printf("-- ref --\n")
+printf("%s\n", `#{ARGV[0]} -#{$MAX}`)
+printf("-- new --\n")
+printf("%s\n", `#{ARGV[1]} -#{$MAX}`)
+
+printf("\nFailed test number is %d, you can reproduce the problematic conditions\n", $MAX)
+printf("by running 'scaling-test -%d'\n", $MAX)
diff --git a/test/scaling-test.c b/test/scaling-test.c
new file mode 100644
index 00000000..ff24b1d4
--- /dev/null
+++ b/test/scaling-test.c
@@ -0,0 +1,261 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "pixman.h"
+
+/* A primitive pseudorandom number generator, taken from POSIX.1-2001 example */
+
+static uint32_t lcg_seed;
+
+uint32_t lcg_rand(void)
+{
+    lcg_seed = lcg_seed * 1103515245 + 12345;
+    return ((uint32_t)(lcg_seed / 65536) % 32768);
+}
+
+void lcg_srand(uint32_t seed)
+{
+    lcg_seed = seed;
+}
+
+uint32_t lcg_rand_n(int max)
+{
+    return lcg_rand() % max;
+}
+
+/*----------------------------------------------------------------------------*\
+ *  CRC-32 version 2.0.0 by Craig Bruce, 2006-04-29.
+ *
+ *  This program generates the CRC-32 values for the files named in the
+ *  command-line arguments.  These are the same CRC-32 values used by GZIP,
+ *  PKZIP, and ZMODEM.  The Crc32_ComputeBuf() can also be detached and
+ *  used independently.
+ *
+ *  THIS PROGRAM IS PUBLIC-DOMAIN SOFTWARE.
+ *
+ *  Based on the byte-oriented implementation "File Verification Using CRC"
+ *  by Mark R. Nelson in Dr. Dobb's Journal, May 1992, pp. 64-67.
+ *
+ *  v1.0.0: original release.
+ *  v1.0.1: fixed printf formats.
+ *  v1.0.2: fixed something else.
+ *  v1.0.3: replaced CRC constant table by generator function.
+ *  v1.0.4: reformatted code, made ANSI C.  1994-12-05.
+ *  v2.0.0: rewrote to use memory buffer & static table, 2006-04-29.
+\*----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------*\
+ *  NAME:
+ *     Crc32_ComputeBuf() - computes the CRC-32 value of a memory buffer
+ *  DESCRIPTION:
+ *     Computes or accumulates the CRC-32 value for a memory buffer.
+ *     The 'inCrc32' gives a previously accumulated CRC-32 value to allow
+ *     a CRC to be generated for multiple sequential buffer-fuls of data.
+ *     The 'inCrc32' for the first buffer must be zero.
+ *  ARGUMENTS:
+ *     inCrc32 - accumulated CRC-32 value, must be 0 on first call
+ *     buf     - buffer to compute CRC-32 value for
+ *     bufLen  - number of bytes in buffer
+ *  RETURNS:
+ *     crc32 - computed CRC-32 value
+ *  ERRORS:
+ *     (no errors are possible)
+\*----------------------------------------------------------------------------*/
+
+static uint32_t Crc32_ComputeBuf( uint32_t inCrc32, const void *buf,
+                                       size_t bufLen )
+{
+    static const uint32_t crcTable[256] = {
+   0x00000000,0x77073096,0xEE0E612C,0x990951BA,0x076DC419,0x706AF48F,0xE963A535,
+   0x9E6495A3,0x0EDB8832,0x79DCB8A4,0xE0D5E91E,0x97D2D988,0x09B64C2B,0x7EB17CBD,
+   0xE7B82D07,0x90BF1D91,0x1DB71064,0x6AB020F2,0xF3B97148,0x84BE41DE,0x1ADAD47D,
+   0x6DDDE4EB,0xF4D4B551,0x83D385C7,0x136C9856,0x646BA8C0,0xFD62F97A,0x8A65C9EC,
+   0x14015C4F,0x63066CD9,0xFA0F3D63,0x8D080DF5,0x3B6E20C8,0x4C69105E,0xD56041E4,
+   0xA2677172,0x3C03E4D1,0x4B04D447,0xD20D85FD,0xA50AB56B,0x35B5A8FA,0x42B2986C,
+   0xDBBBC9D6,0xACBCF940,0x32D86CE3,0x45DF5C75,0xDCD60DCF,0xABD13D59,0x26D930AC,
+   0x51DE003A,0xC8D75180,0xBFD06116,0x21B4F4B5,0x56B3C423,0xCFBA9599,0xB8BDA50F,
+   0x2802B89E,0x5F058808,0xC60CD9B2,0xB10BE924,0x2F6F7C87,0x58684C11,0xC1611DAB,
+   0xB6662D3D,0x76DC4190,0x01DB7106,0x98D220BC,0xEFD5102A,0x71B18589,0x06B6B51F,
+   0x9FBFE4A5,0xE8B8D433,0x7807C9A2,0x0F00F934,0x9609A88E,0xE10E9818,0x7F6A0DBB,
+   0x086D3D2D,0x91646C97,0xE6635C01,0x6B6B51F4,0x1C6C6162,0x856530D8,0xF262004E,
+   0x6C0695ED,0x1B01A57B,0x8208F4C1,0xF50FC457,0x65B0D9C6,0x12B7E950,0x8BBEB8EA,
+   0xFCB9887C,0x62DD1DDF,0x15DA2D49,0x8CD37CF3,0xFBD44C65,0x4DB26158,0x3AB551CE,
+   0xA3BC0074,0xD4BB30E2,0x4ADFA541,0x3DD895D7,0xA4D1C46D,0xD3D6F4FB,0x4369E96A,
+   0x346ED9FC,0xAD678846,0xDA60B8D0,0x44042D73,0x33031DE5,0xAA0A4C5F,0xDD0D7CC9,
+   0x5005713C,0x270241AA,0xBE0B1010,0xC90C2086,0x5768B525,0x206F85B3,0xB966D409,
+   0xCE61E49F,0x5EDEF90E,0x29D9C998,0xB0D09822,0xC7D7A8B4,0x59B33D17,0x2EB40D81,
+   0xB7BD5C3B,0xC0BA6CAD,0xEDB88320,0x9ABFB3B6,0x03B6E20C,0x74B1D29A,0xEAD54739,
+   0x9DD277AF,0x04DB2615,0x73DC1683,0xE3630B12,0x94643B84,0x0D6D6A3E,0x7A6A5AA8,
+   0xE40ECF0B,0x9309FF9D,0x0A00AE27,0x7D079EB1,0xF00F9344,0x8708A3D2,0x1E01F268,
+   0x6906C2FE,0xF762575D,0x806567CB,0x196C3671,0x6E6B06E7,0xFED41B76,0x89D32BE0,
+   0x10DA7A5A,0x67DD4ACC,0xF9B9DF6F,0x8EBEEFF9,0x17B7BE43,0x60B08ED5,0xD6D6A3E8,
+   0xA1D1937E,0x38D8C2C4,0x4FDFF252,0xD1BB67F1,0xA6BC5767,0x3FB506DD,0x48B2364B,
+   0xD80D2BDA,0xAF0A1B4C,0x36034AF6,0x41047A60,0xDF60EFC3,0xA867DF55,0x316E8EEF,
+   0x4669BE79,0xCB61B38C,0xBC66831A,0x256FD2A0,0x5268E236,0xCC0C7795,0xBB0B4703,
+   0x220216B9,0x5505262F,0xC5BA3BBE,0xB2BD0B28,0x2BB45A92,0x5CB36A04,0xC2D7FFA7,
+   0xB5D0CF31,0x2CD99E8B,0x5BDEAE1D,0x9B64C2B0,0xEC63F226,0x756AA39C,0x026D930A,
+   0x9C0906A9,0xEB0E363F,0x72076785,0x05005713,0x95BF4A82,0xE2B87A14,0x7BB12BAE,
+   0x0CB61B38,0x92D28E9B,0xE5D5BE0D,0x7CDCEFB7,0x0BDBDF21,0x86D3D2D4,0xF1D4E242,
+   0x68DDB3F8,0x1FDA836E,0x81BE16CD,0xF6B9265B,0x6FB077E1,0x18B74777,0x88085AE6,
+   0xFF0F6A70,0x66063BCA,0x11010B5C,0x8F659EFF,0xF862AE69,0x616BFFD3,0x166CCF45,
+   0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,
+   0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,
+   0x47B2CF7F,0x30B5FFE9,0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,
+   0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,
+   0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D };
+    uint32_t crc32;
+    unsigned char *byteBuf;
+    size_t i;
+
+    /** accumulate crc32 for buffer **/
+    crc32 = inCrc32 ^ 0xFFFFFFFF;
+    byteBuf = (unsigned char*) buf;
+    for (i=0; i < bufLen; i++) {
+        crc32 = (crc32 >> 8) ^ crcTable[ (crc32 ^ byteBuf[i]) & 0xFF ];
+    }
+    return( crc32 ^ 0xFFFFFFFF );
+}
+
+
+#define MAX_SRC_WIDTH  100
+#define MAX_SRC_HEIGHT 100
+#define MAX_DST_WIDTH  100
+#define MAX_DST_HEIGHT 100
+#define MAX_STRIDE     16
+
+/*
+ * Composite operation with pseudorandom images
+ */
+uint32_t test_composite(uint32_t initcrc, int testnum, int verbose)
+{
+    int i;
+    pixman_image_t *src_img;
+    pixman_image_t *dst_img;
+    pixman_transform_t transform;
+    pixman_region16_t clip;
+    int src_width, src_height;
+    int dst_width, dst_height;
+    int src_stride, dst_stride;
+    int src_x, src_y;
+    int dst_x, dst_y;
+    int src_bpp;
+    int dst_bpp;
+    int w, h;
+    int scale_x = 32768, scale_y = 32768;
+    int op;
+    int repeat = 0;
+    int src_fmt, dst_fmt;
+    uint32_t *srcbuf;
+    uint32_t *dstbuf;
+    uint32_t crc32;
+
+    lcg_srand(testnum);
+
+    src_bpp = /*(lcg_rand_n(2) == 0) ? 2 :*/ 4;
+    dst_bpp = /*(lcg_rand_n(2) == 0) ? 2 :*/ 4;
+    op = (lcg_rand_n(2) == 0) ? PIXMAN_OP_SRC : PIXMAN_OP_OVER;
+
+    src_width = lcg_rand_n(MAX_SRC_WIDTH) + 1;
+    src_height = lcg_rand_n(MAX_SRC_HEIGHT) + 1;
+    dst_width = lcg_rand_n(MAX_DST_WIDTH) + 1;
+    dst_height = lcg_rand_n(MAX_DST_HEIGHT) + 1;
+    src_stride = src_width * src_bpp + lcg_rand_n(MAX_STRIDE) * src_bpp;
+    dst_stride = dst_width * dst_bpp + lcg_rand_n(MAX_STRIDE) * dst_bpp;
+
+    src_x = -src_width + lcg_rand_n(src_width * 3);
+    src_y = -src_height + lcg_rand_n(src_height * 3);
+    dst_x = -dst_width + lcg_rand_n(dst_width * 2);
+    dst_y = -dst_height + lcg_rand_n(dst_height * 3);
+
+    srcbuf = (uint32_t *)malloc(src_stride * src_height);
+    dstbuf = (uint32_t *)malloc(dst_stride * dst_height);
+    for (i = 0; i < src_stride * src_height; i++)
+        *((uint8_t *)srcbuf + i) = lcg_rand_n(256);
+    for (i = 0; i < dst_stride * dst_height; i++)
+        *((uint8_t *)dstbuf + i) = lcg_rand_n(256);
+
+    src_fmt = src_bpp == 4 ? (lcg_rand_n(2) == 0 ?
+        PIXMAN_a8r8g8b8 : PIXMAN_x8r8g8b8) : PIXMAN_r5g6b5;
+
+    dst_fmt = dst_bpp == 4 ? (lcg_rand_n(2) == 0 ?
+        PIXMAN_a8r8g8b8 : PIXMAN_x8r8g8b8) : PIXMAN_r5g6b5;
+
+    src_img = pixman_image_create_bits(
+        src_fmt, src_width, src_height, srcbuf, src_stride);
+
+    dst_img = pixman_image_create_bits(
+        dst_fmt, dst_width, dst_height, dstbuf, dst_stride);
+
+    if (lcg_rand_n(2) == 0) {
+	scale_x = 32768 + lcg_rand_n(65536);
+	scale_y = 32768 + lcg_rand_n(65536);
+        pixman_transform_init_scale(&transform, scale_x, scale_y);
+        pixman_image_set_transform(src_img, &transform);
+    }
+
+    switch (lcg_rand_n(4)) {
+        case 0: repeat = PIXMAN_REPEAT_NONE; break;
+        case 1: repeat = PIXMAN_REPEAT_NORMAL; break;
+        case 2: repeat = PIXMAN_REPEAT_PAD; break;
+        case 3: repeat = PIXMAN_REPEAT_REFLECT; break;
+    }
+    pixman_image_set_repeat(src_img, repeat);
+
+    w = lcg_rand_n(MAX_DST_WIDTH * 2);
+    h = lcg_rand_n(MAX_DST_HEIGHT * 2);
+
+    if (verbose) {
+        printf("op=%d, scale_x=%d, scale_y=%d, repeat=%d\n",
+            op, scale_x, scale_y, repeat);
+        printf("src_width=%d, src_height=%d, dst_width=%d, dst_height=%d\n",
+            src_width, src_height, dst_width, dst_height);
+        printf("src_x=%d, src_y=%d, dst_x=%d, dst_y=%d\n",
+            src_x, src_y, dst_x, dst_y);
+        printf("w=%d, h=%d\n", w, h);
+    }
+
+    pixman_image_composite (op, src_img, NULL, dst_img,
+                            src_x, src_y, 0, 0, dst_x, dst_y, w, h);
+
+    if (verbose) {
+        int j;
+        for (i = 0; i < dst_height; i++) {
+            for (j = 0; j < dst_stride; j++) {
+                printf("%02X ", *((uint8_t *)dstbuf + i * dst_stride + j));
+            }
+            printf("\n");
+        }
+    }
+
+    pixman_image_unref (src_img);
+    pixman_image_unref (dst_img);
+
+    crc32 = Crc32_ComputeBuf(initcrc, dstbuf, dst_stride * dst_height);
+    free(srcbuf);
+    free(dstbuf);
+    return crc32;
+}
+
+int main(int argc, char *argv[])
+{
+    int i, n = 0;
+    uint32_t crc = 0;
+
+    if (argc >= 2)
+        n = atoi(argv[1]);
+
+    if (n == 0) n = 10000;
+
+    if (n < 0) {
+        crc = test_composite(0, -n, 1);
+        printf("crc32=%08X\n", crc);
+    }
+    else {
+        for (i = 1; i <= n; i++)
+        {
+            crc = test_composite(crc, i, 0);
+        }
+        printf("crc32=%08X\n", crc);
+    }
+    return 0;
+}
diff --git a/test/trap-test.c b/test/trap-test.c
new file mode 100644
index 00000000..7750e5a2
--- /dev/null
+++ b/test/trap-test.c
@@ -0,0 +1,126 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <gtk/gtk.h>
+#include "pixman.h"
+
+GdkPixbuf *
+pixbuf_from_argb32 (uint32_t *bits,
+		    int width,
+		    int height,
+		    int stride)
+{
+    GdkPixbuf *pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE,
+					8, width, height);
+    int p_stride = gdk_pixbuf_get_rowstride (pixbuf);
+    guint32 *p_bits = (guint32 *)gdk_pixbuf_get_pixels (pixbuf);
+    int w, h;
+    
+    for (h = 0; h < height; ++h)
+    {
+	for (w = 0; w < width; ++w)
+	{
+	    uint32_t argb = bits[h * stride + w];
+	    guint r, g, b, a;
+	    char *pb = p_bits;
+
+	    pb += h * p_stride + w * 4;
+
+	    r = (argb & 0x00ff0000) >> 16;
+	    g = (argb & 0x0000ff00) >> 8;
+	    b = (argb & 0x000000ff) >> 0;
+	    a = (argb & 0xff000000) >> 24;
+
+	    if (a)
+	    {
+		r = (r * 255) / a;
+		g = (g * 255) / a;
+		b = (b * 255) / a;
+	    }
+
+	    pb[0] = r;
+	    pb[1] = g;
+	    pb[2] = b;
+	    pb[3] = a;
+	}
+    }
+    
+    return pixbuf;
+}
+
+static gboolean
+on_expose (GtkWidget *widget, GdkEventExpose *expose, gpointer data)
+{
+    GdkPixbuf *pixbuf = data;
+    
+    gdk_draw_pixbuf (widget->window, NULL,
+		     pixbuf, 0, 0, 0, 0,
+		     gdk_pixbuf_get_width (pixbuf),
+		     gdk_pixbuf_get_height (pixbuf),
+		     GDK_RGB_DITHER_NONE,
+		     0, 0);
+    
+    return TRUE;
+}
+
+static void
+show_window (uint32_t *bits, int w, int h, int stride)
+{
+    GdkPixbuf *pixbuf;
+    
+    GtkWidget *window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+    
+    pixbuf = pixbuf_from_argb32 (bits, w, h, stride);
+    
+    g_signal_connect (window, "expose_event", G_CALLBACK (on_expose), pixbuf);
+    g_signal_connect (window, "delete_event", G_CALLBACK (gtk_main_quit), NULL);
+    
+    gtk_widget_show (window);
+    
+    gtk_main ();
+}
+
+int
+main (int argc, char **argv)
+{
+#define WIDTH 200
+#define HEIGHT 200
+
+    pixman_image_t *src_img;
+    pixman_image_t *mask_img;
+    pixman_image_t *dest_img;
+    pixman_trap_t trap;
+    pixman_color_t white = { 0x0000, 0xffff, 0x0000, 0xffff };
+    uint32_t *bits = malloc (WIDTH * HEIGHT * 4);
+    uint32_t *mbits = malloc (WIDTH * HEIGHT);
+
+    memset (mbits, 0, WIDTH * HEIGHT);
+    memset (bits, 0xff, WIDTH * HEIGHT * 4);
+    
+    trap.top.l = pixman_int_to_fixed (50) + 0x8000;
+    trap.top.r = pixman_int_to_fixed (150) + 0x8000;
+    trap.top.y = pixman_int_to_fixed (30);
+
+    trap.bot.l = pixman_int_to_fixed (50) + 0x8000;
+    trap.bot.r = pixman_int_to_fixed (150) + 0x8000;
+    trap.bot.y = pixman_int_to_fixed (150);
+
+    mask_img = pixman_image_create_bits (PIXMAN_a8, WIDTH, HEIGHT, mbits, WIDTH);
+    src_img = pixman_image_create_solid_fill (&white);
+    dest_img = pixman_image_create_bits (PIXMAN_a8r8g8b8, WIDTH, HEIGHT, bits, WIDTH * 4);
+    
+    pixman_add_traps (mask_img, 0, 0, 1, &trap);
+
+    pixman_image_composite (PIXMAN_OP_OVER,
+			    src_img, mask_img, dest_img,
+			    0, 0, 0, 0, 0, 0, WIDTH, HEIGHT);
+    
+    gtk_init (&argc, &argv);
+    
+    show_window (bits, WIDTH, HEIGHT, WIDTH);
+    
+    pixman_image_unref (src_img);
+    pixman_image_unref (dest_img);
+    free (bits);
+    
+    return 0;
+}