Merge pull request #5562 from radarhere/expand

Corrected border position for P mode in ImageOps.expand()

Tests/test_imageops.py

@@ -161,7 +161,13 @@ def test_expand_palette():
     im_expanded = ImageOps.expand(im, 10, (255, 0, 0))
 
     px = im_expanded.convert("RGB").load()
-    assert px[0, 0] == (255, 0, 0)
+    for b in range(10):
+        for x in range(im_expanded.width):
+            assert px[x, b] == (255, 0, 0)
+            assert px[x, im_expanded.height - 1 - b] == (255, 0, 0)
+        for y in range(im_expanded.height):
+            assert px[b, x] == (255, 0, 0)
+            assert px[b, im_expanded.width - 1 - b] == (255, 0, 0)
 
     im_cropped = im_expanded.crop(
         (10, 10, im_expanded.width - 10, im_expanded.height - 10)

src/PIL/ImageOps.py

@@ -399,7 +399,7 @@ def expand(image, border=0, fill=0):
         out.paste(image, (left, top))
 
         draw = ImageDraw.Draw(out)
-        draw.rectangle((0, 0, width, height), outline=color, width=border)
+        draw.rectangle((0, 0, width - 1, height - 1), outline=color, width=border)
     else:
         out = Image.new(image.mode, (width, height), color)
         out.paste(image, (left, top))