X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=scripts%2Fsnapdiff.py;h=0ed3937a8f8e669accf577c4b06d6472784e3c57;hb=ae2b4d32ed56e3ac193cc7205aeb58082c448ce8;hp=fa634fcf49c9a444d891f2dee0436cb542f4a9ba;hpb=0c881f7e9fd139ed13f9e81d761b9393bb08ed15;p=apitrace

diff --git a/scripts/snapdiff.py b/scripts/snapdiff.py
index fa634fc..0ed3937 100755
--- a/scripts/snapdiff.py
+++ b/scripts/snapdiff.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 ##########################################################################
 #
+# Copyright 2011 Jose Fonseca
 # Copyright 2008-2009 VMware, Inc.
 # All Rights Reserved.
 #
@@ -25,23 +26,73 @@
 ##########################################################################/
 
 
+'''Snapshot (image) comparison script.
+'''
+
+
 import sys
 import os.path
-import subprocess
 import optparse
+import math
+import operator
 
-import Image
+from PIL import Image
+from PIL import ImageChops
+from PIL import ImageEnhance
 
 
 thumb_size = 320, 320
 
 
-def compare(im, ref):
-    import ImageMath
-    # See http://www.pythonware.com/library/pil/handbook/imagemath.htm
-    mask = ImageMath.eval("min(abs(a - b), 1)", a=im, b=ref)
-    gray = ref.convert('L')
-    # TODO
+class Comparer:
+    '''Image comparer.'''
+
+    def __init__(self, ref_image, src_image, alpha = False):
+        if isinstance(ref_image, basestring):
+            self.ref_im = Image.open(ref_image)
+        else:
+            self.ref_im = ref_image
+
+        if isinstance(src_image, basestring):
+            self.src_im = Image.open(src_image)
+        else:
+            self.src_im = src_image
+
+        # Ignore
+        if not alpha:
+            self.ref_im = self.ref_im.convert('RGB')
+            self.src_im = self.src_im.convert('RGB')
+
+        self.diff = ImageChops.difference(self.src_im, self.ref_im)
+
+    def write_diff(self, diff_image, fuzz = 0.05):
+        # make a difference image similar to ImageMagick's compare utility
+        mask = ImageEnhance.Brightness(self.diff).enhance(1.0/fuzz)
+        mask = mask.convert('L')
+
+        lowlight = Image.new('RGB', self.src_im.size, (0xff, 0xff, 0xff))
+        highlight = Image.new('RGB', self.src_im.size, (0xf1, 0x00, 0x1e))
+        diff_im = Image.composite(highlight, lowlight, mask)
+
+        diff_im = Image.blend(self.src_im, diff_im, 0xcc/255.0)
+        diff_im.save(diff_image)
+
+    def precision(self):
+        # See also http://effbot.org/zone/pil-comparing-images.htm
+        h = self.diff.histogram()
+        square_error = 0
+        for i in range(1, 256):
+            square_error += sum(h[i : 3*256: 256])*i*i
+        rel_error = float(square_error*2 + 1) / float(self.diff.size[0]*self.diff.size[1]*3*255*255*2)
+        bits = -math.log(rel_error)/math.log(2.0)
+        return bits
+
+    def ae(self):
+        # Compute absolute error
+        # TODO: this is approximate due to the grayscale conversion
+        h = self.diff.convert('L').histogram()
+        ae = sum(h[int(255 * fuzz) + 1 : 256])
+        return ae
 
 
 def surface(html, image):
@@ -84,17 +135,23 @@ def find_images(prefix):
 
 
 def main():
+    global options
+
     optparser = optparse.OptionParser(
         usage="\n\t%prog [options] <ref_prefix> <src_prefix>",
         version="%%prog")
     optparser.add_option(
         '-o', '--output', metavar='FILE',
-        type="string", dest="output",
-        help="output filename [stdout]")
+        type="string", dest="output", default='index.html',
+        help="output filename [default: %default]")
     optparser.add_option(
         '-f', '--fuzz',
-        type="string", dest="fuzz", default='5%',
-        help="fuzz [default: %default]")
+        type="float", dest="fuzz", default=0.05,
+        help="fuzz ratio [default: %default]")
+    optparser.add_option(
+        '--overwrite',
+        action="store_true", dest="overwrite", default=False,
+        help="overwrite")
 
     (options, args) = optparser.parse_args(sys.argv[1:])
 
@@ -123,10 +180,13 @@ def main():
         root, ext = os.path.splitext(src_image)
         delta_image = "%s.diff.png" % (root, )
         if os.path.exists(ref_image) and os.path.exists(src_image):
-            if not os.path.exists(delta_image) \
+            if options.overwrite \
+               or not os.path.exists(delta_image) \
                or (os.path.getmtime(delta_image) < os.path.getmtime(ref_image) \
                    and os.path.getmtime(delta_image) < os.path.getmtime(src_image)):
-                subprocess.call(["compare", '-metric', 'AE', '-fuzz', options.fuzz, ref_image, src_image, delta_image])
+
+                comparer = Comparer(ref_image, src_image)
+                comparer.write_diff(delta_image, fuzz=options.fuzz)
 
             html.write('      <tr>\n')
             surface(html, ref_image)