order ImageDraw.rounded_rectangle() points

Tests/test_imagedraw.py

@@ -735,6 +735,22 @@ def test_rounded_rectangle(xy):
     assert_image_equal_tofile(im, "Tests/images/imagedraw_rounded_rectangle.png")
 
 
+@pytest.mark.parametrize(
+    "xy",
+    ((10, 20, 190, 180), (190, 20, 10, 180), (190, 180, 10, 20), (10, 180, 190, 20)),
+)
+def test_rounded_rectangle_unordered_points(xy):
+    # Arrange
+    im = Image.new("RGB", (200, 200))
+    draw = ImageDraw.Draw(im)
+
+    # Act
+    draw.rounded_rectangle(xy, 30, fill="red", outline="green", width=5)
+
+    # Assert
+    assert_image_equal_tofile(im, "Tests/images/imagedraw_rounded_rectangle.png")
+
+
 @pytest.mark.parametrize(
     "xy, radius, type",
     [

src/PIL/ImageDraw.py

@@ -301,6 +301,7 @@ class ImageDraw:
             (x0, y0), (x1, y1) = xy
         else:
             x0, y0, x1, y1 = xy
+        x0, y0, x1, y1 = min(x0, x1), min(y0, y1), max(x0, x1), max(y0, y1)
 
         d = radius * 2