Add fuzzy image matching tool for Linux pixel tests

Review URL: http://codereview.chromium.org/13159


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6444 0039d316-1c4b-4281-b951-d872f2087c98

third_party/fuzzymatch/SConstruct

@@ -0,0 +1 @@
+Program('fuzzymatch.c', LIBS = ['lept', 'png', 'jpeg', 'tiff', 'z', 'm'])

third_party/fuzzymatch/fuzzymatch.c

@@ -0,0 +1,98 @@
+// Copyright (c) 2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/* Fuzzy pixel test matching.
+ *
+ * This is designed to compare two layout test images (RGB 800x600) and manage
+ * to ignore the noise caused by the font renderers choosing slightly different
+ * pixels.
+ *
+ *    A             B
+ *    |             |
+ *    |--->delta<---|
+ *           |
+ *           V
+ *          gray
+ *           |
+ *           V
+ *         binary
+ *           |
+ *    |-------------|
+ *    |             |
+ *   1x3           3x1   Morphological openings
+ *    |             |
+ *    |-----OR------|
+ *           |
+ *           V
+ *     count pixels
+ *
+ * The result is that three different pixels in a row (vertically or
+ * horizontally) will cause the match to fail and the binary exits with code 1.
+ * Otherwise the binary exists with code 0.
+ *
+ * This requires leptonica to be installed. On Ubuntu do
+ *   # apt-get install libleptonica libleptonica-dev
+ *
+ * Build with:
+ *   % gcc -o fuzzymatch fuzzymatch.c -llept -ljpeg -ltiff -lpng -lz -lm -Wall -O2
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <leptonica/allheaders.h>
+
+static int
+usage(const char *argv0) {
+  fprintf(stderr, "Usage: %s <input a> <input b>\n", argv0);
+  return 1;
+}
+
+int
+main(int argc, char **argv) {
+  if (argc != 3)
+    return usage(argv[0]);
+
+  PIX *a = pixRead(argv[1]);
+  PIX *b = pixRead(argv[2]);
+
+  if (!a) {
+    fprintf(stderr, "Failed to open %s\n", argv[1]);
+    return 1;
+  }
+
+  if (!b) {
+    fprintf(stderr, "Failed to open %s\n", argv[1]);
+    return 1;
+  }
+
+  if (pixGetWidth(a) != pixGetWidth(b) ||
+      pixGetHeight(a) != pixGetHeight(b)) {
+    fprintf(stderr, "Inputs are difference sizes\n");
+    return 1;
+  }
+
+  PIX *delta = pixAbsDifference(a, b);
+  pixInvert(delta, delta);
+  pixDestroy(&a);
+  pixDestroy(&b);
+
+  PIX *deltagray = pixConvertRGBToGray(delta, 0, 0, 0);
+  pixDestroy(&delta);
+
+  PIX *deltabinary = pixThresholdToBinary(deltagray, 254);
+
+  PIX *hopened = pixOpenBrick(NULL, deltabinary, 3, 1);
+  PIX *vopened = pixOpenBrick(NULL, deltabinary, 1, 3);
+  pixDestroy(&deltabinary);
+
+  PIX *opened = pixOr(NULL, hopened, vopened);
+  pixDestroy(&hopened);
+  pixDestroy(&vopened);
+
+  l_int32 count;
+  pixCountPixels(opened, &count, NULL);
+  fprintf(stderr, "%d\n", count);
+
+  return count;
+}

webkit/tools/layout_tests/layout_package/test_failures.py

@@ -202,3 +202,10 @@ def Message():
     # to the PNGs rather than the checksums.
     return "Image mismatch"
 
+class FailureFuzzyFailure(FailureWithType):
+  """Image hashes didn't match."""
+  OUT_FILENAMES = ["-actual-win.png", "-expected.png"]
+
+  @staticmethod
+  def Message():
+    return "Fuzzy image match also failed"

webkit/tools/layout_tests/run_webkit_tests.py

@@ -39,6 +39,7 @@
 from layout_package import path_utils
 from layout_package import test_failures
 from layout_package import test_shell_thread
+from test_types import fuzzy_image_diff
 from test_types import image_diff
 from test_types import test_type_base
 from test_types import text_diff
@@ -597,6 +598,8 @@ def main(options, args):
   test_runner.AddTestType(simplified_text_diff.SimplifiedTextDiff)
   if not options.no_pixel_tests:
     test_runner.AddTestType(image_diff.ImageDiff)
+    if options.fuzzy_pixel_tests:
+      test_runner.AddTestType(fuzzy_image_diff.FuzzyImageDiff)
   has_new_failures = test_runner.Run()
   logging.info("Exit status: %d" % has_new_failures)
   sys.exit(has_new_failures)
@@ -606,6 +609,10 @@ def main(options, args):
   option_parser.add_option("", "--no-pixel-tests", action="store_true",
                            default=False,
                            help="disable pixel-to-pixel PNG comparisons")
+  option_parser.add_option("", "--fuzzy-pixel-tests", action="store_true",
+                           default=False,
+                           help="Also use fuzzy matching to compare pixel test "
+                                "outputs.")
   option_parser.add_option("", "--results-directory",
                            default="layout-test-results",
                            help="Output results directory source dir,"