Merge branch 'coreman14/master'

Close #144

Author: whtsky

pixelmatch/contrib/PIL.py

@@ -17,6 +17,7 @@ def pixelmatch(
     aa_color: RGBTuple = (255, 255, 0),
     diff_color: RGBTuple = (255, 0, 0),
     diff_mask: bool = False,
+    fail_fast: bool = False,
 ) -> int:
     """
     Compares two images, writes the output diff and returns the number of mismatched pixels.
@@ -36,7 +37,8 @@ def pixelmatch(
         defaults to (255, 0, 0) (red)
     :param diff_mask: whether or not to draw the diff over a transparent background (a mask),
         defaults to False
-    :return: number of pixels that are different
+    :param fail_fast: if true, will return after first different pixel. Defaults to false
+    :return: number of pixels that are different or 1 if fail_fast == true
     """
     width, height = img1.size
     img1 = from_PIL_to_raw_data(img1)
@@ -59,6 +61,7 @@ def pixelmatch(
         aa_color=aa_color,
         diff_color=diff_color,
         diff_mask=diff_mask,
+        fail_fast=fail_fast,
     )
 
     if raw_output is not None and output is not None:

pixelmatch/core.py

@@ -16,6 +16,7 @@ def pixelmatch(
     aa_color: RGBTuple = (255, 255, 0),
     diff_color: RGBTuple = (255, 0, 0),
     diff_mask: bool = False,
+    fail_fast: bool = False,
 ) -> int:
     """
     Compares two images, writes the output diff and returns the number of mismatched pixels.
@@ -37,7 +38,8 @@ def pixelmatch(
         defaults to (255, 0, 0) (red)
     :param diff_mask: whether or not to draw the diff over a transparent background (a mask),
         defaults to False
-    :return: number of pixels that are different
+    :param fail_fast: if true, will return after first different pixel. Defaults to false
+    :return: number of pixels that are different or 1 if fail_fast == true
     """
 
     if len(img1) != len(img2):
@@ -93,6 +95,8 @@ def pixelmatch(
                     # found substantial difference not caused by anti-aliasing; draw it as red
                     if output:
                         draw_pixel(output, pos, diffR, diffG, diffB)
+                    if fail_fast:
+                        return 1
                     diff += 1
 
             elif output:

test_pixelmatch.py

@@ -83,6 +83,25 @@ def test_pixelmatch(
     assert mismatch == mismatch2, "number of mismatched pixels without diff"
 
 
+@pytest.mark.parametrize(
+    "img_path_1,img_path_2,diff_path,options,expected_mismatch", testdata
+)
+def test_pixelmatch_failfast(
+    img_path_1: str,
+    img_path_2: str,
+    diff_path: str,
+    options: Dict,
+    expected_mismatch: int,
+    benchmark,
+):
+    img1 = read_img(img_path_1)
+    img2 = read_img(img_path_2)
+    width, height = img1.size
+    img1_data = pil_to_flatten_data(img1)
+    img2_data = pil_to_flatten_data(img2)
+    if expected_mismatch:
+        assert benchmark(pixelmatch, img1_data, img2_data, width, height, fail_fast=True, **options) == 1
+
 @pytest.mark.parametrize(
     "img_path_1,img_path_2,diff_path,options,expected_mismatch", testdata
 )