1 files changed, 306 insertions, 0 deletions
diff --git a/test/buffer-diff.c b/test/buffer-diff.c
new file mode 100644
index 00000000..b59b5e89
--- /dev/null
+++ b/test/buffer-diff.c
@@ -0,0 +1,306 @@
+/* imagediff - Compare two images
+ *
+ * Copyright © 2004 Richard D. Worth
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Richard Worth
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.
+ * Richard Worth makes no representations about the suitability of this
+ * software for any purpose.  It is provided "as is" without express
+ * or implied warranty.
+ *
+ * RICHARD WORTH DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL RICHARD WORTH BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author: Richard D. Worth <richard@theworths.org> */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <errno.h>
+#include <string.h>
+#include <pixman.h>
+
+#include "cairo-test.h"
+
+#include "buffer-diff.h"
+#include "xmalloc.h"
+
+static void
+xunlink (const char *pathname)
+{
+    if (unlink (pathname) < 0 && errno != ENOENT) {
+	cairo_test_log ("  Error: Cannot remove %s: %s\n",
+			pathname, strerror (errno));
+	exit (1);
+    }
+}
+
+/* This function should be rewritten to compare all formats supported by
+ * cairo_format_t instead of taking a mask as a parameter.
+ */
+static int
+buffer_diff_core (unsigned char *_buf_a,
+		  unsigned char *_buf_b,
+		  unsigned char *_buf_diff,
+		  int		width,
+		  int		height,
+		  int		stride_a,
+		  int		stride_b,
+		  int		stride_diff,
+		  pixman_bits_t mask)
+{
+    int x, y;
+    pixman_bits_t *row_a, *row_b, *row;
+    int pixels_changed = 0;
+    pixman_bits_t *buf_a = (pixman_bits_t*)_buf_a;
+    pixman_bits_t *buf_b = (pixman_bits_t*)_buf_b;
+    pixman_bits_t *buf_diff = (pixman_bits_t*)_buf_diff;
+
+    stride_a /= sizeof(pixman_bits_t);
+    stride_b /= sizeof(pixman_bits_t);
+    stride_diff /= sizeof(pixman_bits_t);
+    for (y = 0; y < height; y++)
+    {
+	row_a = buf_a + y * stride_a;
+	row_b = buf_b + y * stride_b;
+	row = buf_diff + y * stride_diff;
+	for (x = 0; x < width; x++)
+	{
+	    /* check if the pixels are the same */
+	    if ((row_a[x] & mask) != (row_b[x] & mask)) {
+		int channel;
+		pixman_bits_t diff_pixel = 0;
+
+		/* calculate a difference value for all 4 channels */
+		for (channel = 0; channel < 4; channel++) {
+		    int value_a = (row_a[x] >> (channel*8)) & 0xff;
+		    int value_b = (row_b[x] >> (channel*8)) & 0xff;
+		    unsigned int diff;
+		    diff = abs (value_a - value_b);
+		    diff *= 4;  /* emphasize */
+		    if (diff)
+		        diff += 128; /* make sure it's visible */
+		    if (diff > 255)
+		        diff = 255;
+		    diff_pixel |= diff << (channel*8);
+		}
+
+		pixels_changed++;
+		row[x] = diff_pixel;
+	    } else {
+		row[x] = 0;
+	    }
+	    row[x] |= 0xff000000; /* Set ALPHA to 100% (opaque) */
+	}
+    }
+
+    return pixels_changed;
+}
+
+int
+buffer_diff (unsigned char *buf_a,
+	     unsigned char *buf_b,
+	     unsigned char *buf_diff,
+	     int	   width,
+	     int	   height,
+	     int	   stride_a,
+	     int	   stride_b,
+	     int	   stride_diff)
+{
+    return buffer_diff_core(buf_a, buf_b, buf_diff,
+			    width, height, stride_a, stride_b, stride_diff, 0xffffffff);
+}
+
+int
+buffer_diff_noalpha (unsigned char *buf_a,
+		     unsigned char *buf_b,
+		     unsigned char *buf_diff,
+		     int	   width,
+		     int	   height,
+		     int	   stride_a,
+		     int	   stride_b,
+		     int	   stride_diff)
+{
+    return buffer_diff_core(buf_a, buf_b, buf_diff,
+			    width, height, stride_a, stride_b, stride_diff, 0x00ffffff);
+}
+
+static cairo_status_t
+stdio_write_func (void *closure, const unsigned char *data, unsigned int length)
+{
+    FILE *file = closure;
+
+    if (fwrite (data, 1, length, file) != length)
+	return CAIRO_STATUS_WRITE_ERROR;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+/* Flatten an ARGB surface by blending it over white. The resulting
+ * surface, (still in ARGB32 format, but with only alpha==1.0
+ * everywhere) is returned in the same surface pointer.
+ *
+ * The original surface will be destroyed.
+ *
+ * The (x,y) value specify an origin of interest for the original
+ * image. The flattened image will be generated only from the box
+ * extending from (x,y) to (width,height).
+ */
+static void
+flatten_surface (cairo_surface_t **surface, int x, int y)
+{
+    cairo_surface_t *flat;
+    cairo_t *cr;
+
+    flat = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+				       cairo_image_surface_get_width (*surface) - x,
+				       cairo_image_surface_get_height (*surface) - y);
+    cairo_surface_set_device_offset (flat, -x, -y);
+
+    cr = cairo_create (flat);
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+    cairo_set_source_surface (cr, *surface, 0, 0);
+    cairo_paint (cr);
+    cairo_destroy (cr);
+
+    cairo_surface_destroy (*surface);
+    *surface = flat;
+}
+
+/* Image comparison code courtesy of Richard Worth <richard@theworths.org>
+ * Returns number of pixels changed, (or -1 on error).
+ * Also saves a "diff" image intended to visually show where the
+ * images differ.
+ */
+static int
+image_diff_core (const char *filename_a,
+		 const char *filename_b,
+		 const char *filename_diff,
+		 int		ax,
+		 int		ay,
+		 int		bx,
+		 int		by,
+		 cairo_bool_t	flatten)
+{
+    int pixels_changed;
+    unsigned int width_a, height_a, stride_a;
+    unsigned int width_b, height_b, stride_b;
+    cairo_surface_t *surface_a, *surface_b, *surface_diff;
+
+    surface_a = cairo_image_surface_create_from_png (filename_a);
+    if (cairo_surface_status (surface_a))
+	return -1;
+
+    surface_b = cairo_image_surface_create_from_png (filename_b);
+    if (cairo_surface_status (surface_b)) {
+	cairo_surface_destroy (surface_a);
+	return -1;
+    }
+
+    width_a = cairo_image_surface_get_width (surface_a) - ax;
+    height_a = cairo_image_surface_get_height (surface_a) - ay;
+    width_b = cairo_image_surface_get_width (surface_b) - bx;
+    height_b = cairo_image_surface_get_height (surface_b) - by;
+
+    if (width_a  != width_b  ||
+	height_a != height_b)
+    {
+	cairo_test_log ("Error: Image size mismatch: (%dx%d) vs. (%dx%d)\n"
+			"       for %s vs. %s\n",
+			width_a, height_a,
+			width_b, height_b,
+			filename_a, filename_b);
+	cairo_surface_destroy (surface_a);
+	cairo_surface_destroy (surface_b);
+	return -1;
+    }
+
+    if (flatten) {
+	flatten_surface (&surface_a, ax, ay);
+	flatten_surface (&surface_b, bx, by);
+	ax = ay = bx = by = 0;
+    }
+
+    surface_diff = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+					       width_a, height_a);
+
+    stride_a = cairo_image_surface_get_stride (surface_a);
+    stride_b = cairo_image_surface_get_stride (surface_b);
+
+    pixels_changed = buffer_diff (cairo_image_surface_get_data (surface_a)
+				  + (ay * stride_a) + ax * 4,
+                                  cairo_image_surface_get_data (surface_b)
+				  + (by * stride_b) + by * 4,
+                                  cairo_image_surface_get_data (surface_diff),
+                                  width_a, height_a,
+				  stride_a, stride_b,
+				  cairo_image_surface_get_stride (surface_diff));
+
+    if (pixels_changed) {
+	FILE *png_file;
+
+	if (filename_diff)
+	    png_file = fopen (filename_diff, "wb");
+	else
+	    png_file = stdout;
+
+	cairo_surface_write_to_png_stream (surface_diff, stdio_write_func, png_file);
+
+	if (png_file != stdout)
+	    fclose (png_file);
+    } else {
+	if (filename_diff)
+	    xunlink (filename_diff);
+    }
+
+    cairo_surface_destroy (surface_a);
+    cairo_surface_destroy (surface_b);
+    cairo_surface_destroy (surface_diff);
+
+    return pixels_changed;
+}
+
+int
+image_diff (const char *filename_a,
+	    const char *filename_b,
+	    const char *filename_diff,
+	    int		ax,
+	    int		ay,
+	    int		bx,
+	    int		by)
+{
+    return image_diff_core (filename_a, filename_b, filename_diff,
+			    ax, ay, bx, by,
+			    FALSE);
+}
+
+int
+image_diff_flattened (const char *filename_a,
+		      const char *filename_b,
+		      const char *filename_diff,
+		      int	  ax,
+		      int	  ay,
+		      int	  bx,
+		      int	  by)
+{
+    return image_diff_core (filename_a, filename_b, filename_diff,
+			    ax, ay, bx, by,
+			    TRUE);
+}