Compute image diff even if image dimensions differ

bokeh · bryevdv · Mar 26, 2018 · Jul 10, 2017 · Mar 24, 2018 · Mar 25, 2018
commit d161a418f80170deb418c0bd4c910db580e49a0f
diff --git a/tests/examples/collect_examples.py b/tests/examples/collect_examples.py
@@ -179,10 +179,6 @@ def upload_imgs(self):
     def images_differ(self):
         return self.pixels != 0
 
-    @property
-    def dimensions_differ(self):
-        return self.pixels == -1
-
 def add_examples(list_of_examples, path, examples_dir, example_type=None, slow=None, skip=None, no_js=None, no_diff=None):
     if path == '*':
         example_path = examples_dir

diff --git a/tests/examples/examples_report.jinja b/tests/examples/examples_report.jinja
@@ -77,9 +77,7 @@
               {% if not skipped and not example.no_js %}
                 <a href="{{ example.img_path_or_url }}"><img class="thumbnail" src="{{ example.img_path_or_url }}"></img></a>
                 {% if not example.no_diff %}
-                  {% if example.dimensions_differ %}
-                  <div class="thumbnail">Dimensions differ</div>
-                  {% elif example.images_differ %}
+                  {% if example.images_differ %}
                   <a href="{{ example.diff_path_or_url }}"><img class="thumbnail" src="{{ example.diff_path_or_url }}"></img></a>
                   {% else %}
                   <div class="thumbnail">No diff</div>

diff --git a/tests/examples/test_examples.py b/tests/examples/test_examples.py
@@ -113,7 +113,7 @@ def _get_pdiff(example):
 
         example.pixels = image_diff(diff_path, img_path, ref_path)
         if example.pixels != 0:
-            comment = "dimensions don't match" if example.pixels == -1 else white("%.02f%%" % example.pixels) + " of pixels"
+            comment = white("%.02f%%" % example.pixels) + " of pixels"
             warn("generated and reference images differ: %s" % comment)
         else:
             ok("generated and reference images match")

diff --git a/tests/plugins/image_diff.py b/tests/plugins/image_diff.py
@@ -4,17 +4,23 @@
 logging.getLogger('PIL.PngImagePlugin').setLevel(logging.INFO)
 
 def image_diff(diff_path, before_path, after_path, superimpose=False):
-    """ Returns the percentage of differing pixels or -1 if dimensions differ. """
+    """ Returns the percentage of differing pixels. """
     before = Image.open(before_path)
     after = Image.open(after_path)
 
-    if before.size != after.size:
-        return -1
-
     before = before.convert('RGBA')
     after = after.convert('RGBA')
 
-    mask = ImageChops.difference(before, after)
+    width = max(before.width, after.width)
+    height = max(before.height, after.height)
+
+    resized_before = Image.new("RGBA", (width, height), "white")
+    resized_after = Image.new("RGBA", (width, height), "white")
+
+    resized_before.paste(before)
+    resized_after.paste(after)
+
+    mask = ImageChops.difference(resized_before, resized_after)
     mask = mask.convert('L')
     mask = mask.point(lambda k: 0 if k == 0 else 255)
 
@@ -23,16 +29,15 @@ def image_diff(diff_path, before_path, after_path, superimpose=False):
     else:
         diff = mask.convert('RGB')
         if superimpose:
-            diff.paste(after, mask=mask)
+            diff.paste(resized_after, mask=mask)
         else:
             diff.paste((0, 0, 255), mask=mask)
         diff.save(diff_path)
 
-        w, h = after.size
         pixels = 0
 
         for v in mask.getdata():
             if v == 255:
                 pixels += 1
 
-        return float(pixels)/(w*h)*100
+        return float(pixels)/(width*height)*100