Merge pull request #1 from radarhere/gif_test

Test that background colours read are equal to saved colours

Tests/test_file_gif.py

@@ -317,18 +317,20 @@ def test_save_dispose(self):
 
  def test_dispose2_diff(self):
  out = self.tempfile('temp.gif')
+
  # 4 backgrounds: White, Grey, Black, Red
- im_list = [
- Image.new('RGB', (100, 100), '#fff'),
- Image.new('RGB', (100, 100), '#999'),
- Image.new('RGB', (100, 100), '#000'),
- Image.new('RGB', (100, 100), '#f00'),
- ]
- # Red circle in center of each frame
- for img in im_list:
+ backgrounds = [(255, 255, 255), (153, 153, 153), (0, 0, 0), (255, 0, 0)]
+
+ im_list = []
+ for background in backgrounds:
+ img = Image.new('RGB', (100, 100), background)
+
+ # Red circle in center of each frame
  d = ImageDraw.Draw(img)
  d.ellipse([(40, 40), (60, 60)], fill='#f00')
 
+ im_list.append(img)
+
  im_list[0].save(
  out,
  save_all=True,
@@ -337,24 +339,16 @@ def test_dispose2_diff(self):
  )
 
  img = Image.open(out)
- top_left_pixels = []
- center_pixels = []
 
- for i in range(3):
+ for i, background in enumerate(backgrounds):
+ img.seek(i)
  rgb_img = img.convert('RGB')
- # Get pixel in top left
- r, g, b = rgb_img.getpixel((1, 1))
- top_left_pixels += [(r, g, b)]
- # Get pixel in center
- r, g, b = rgb_img.getpixel((50, 50))
- center_pixels += [(r, g, b)]
- for prev in top_left_pixels[:i]:
- # Change background every frame
- self.assertNotEqual((r, g, b), prev)
- for prev in center_pixels[:i]:
- # Center remains red every frame
- self.assertEqual((r, g, b), (255, 0, 0))
- img.seek(img.tell() + 1)
+
+ # Check top left pixel matches background
+ self.assertEqual(rgb_img.getpixel((0, 0)), background)
+
+ # Center remains red every frame
+ self.assertEqual(rgb_img.getpixel((50, 50)), (255, 0, 0))
 
  def test_iss634(self):
  img = Image.open("Tests/images/iss634.gif")