From e97c26e893908243d16518e52cf9dec21ce93f3e Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Tue, 5 Jan 2021 20:26:55 +1100
Subject: [PATCH] Only draw each rectangle outline pixel once

---
 .../imagedraw_rectangle_translucent_outline.png  | Bin 0 -> 235 bytes
 Tests/test_imagedraw.py                          |  15 +++++++++++++++
 src/libImaging/Draw.c                            |   4 ++--
 3 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 Tests/images/imagedraw_rectangle_translucent_outline.png

diff --git a/Tests/images/imagedraw_rectangle_translucent_outline.png b/Tests/images/imagedraw_rectangle_translucent_outline.png
new file mode 100644
index 0000000000000000000000000000000000000000..845648762ccab1e1d2047f653a9bb6bda4e22e65
GIT binary patch
literal 235
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xg`1c*QWG{!ozG_X+w+aCy0!oaazk99u!FI65z|XXO|?{zfTydU%Q~loCIBtCO<Mo}

literal 0
HcmV?d00001

diff --git a/Tests/test_imagedraw.py b/Tests/test_imagedraw.py
index a87c1f2be44..c88b1ac233d 100644
--- a/Tests/test_imagedraw.py
+++ b/Tests/test_imagedraw.py
@@ -699,6 +699,21 @@ def test_rectangle_I16():
     )
 
 
+def test_rectangle_translucent_outline():
+    # Arrange
+    im = Image.new("RGB", (W, H))
+    draw = ImageDraw.Draw(im, "RGBA")
+
+    # Act
+    draw.rectangle(BBOX1, fill="black", outline=(0, 255, 0, 127), width=5)
+
+    # Assert
+    with Image.open(
+        "Tests/images/imagedraw_rectangle_translucent_outline.png"
+    ) as expected:
+        assert_image_equal(im, expected)
+
+
 def test_floodfill():
     red = ImageColor.getrgb("red")
 
diff --git a/src/libImaging/Draw.c b/src/libImaging/Draw.c
index 8471ffb178d..b6f63b7e804 100644
--- a/src/libImaging/Draw.c
+++ b/src/libImaging/Draw.c
@@ -724,8 +724,8 @@ ImagingDrawRectangle(
         for (i = 0; i < width; i++) {
             draw->hline(im, x0, y0 + i, x1, ink);
             draw->hline(im, x0, y1 - i, x1, ink);
-            draw->line(im, x1 - i, y0, x1 - i, y1, ink);
-            draw->line(im, x0 + i, y1, x0 + i, y0, ink);
+            draw->line(im, x1 - i, y0 + width, x1 - i, y1 - width + 1, ink);
+            draw->line(im, x0 + i, y0 + width, x0 + i, y1 - width + 1, ink);
         }
     }