Added rounded_rectangle method

Tests/test_imagedraw.py

@@ -699,6 +699,35 @@ def test_rectangle_I16():
     )
 
 
+@pytest.mark.parametrize(
+    "xy",
+    [(10, 20, 190, 180), ([10, 20], [190, 180]), ((10, 20), (190, 180))],
+)
+def test_rounded_rectangle(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(im, Image.open("Tests/images/imagedraw_rounded_rectangle.png"))
+
+
+def test_rounded_rectangle_zero_radius():
+    # Arrange
+    im = Image.new("RGB", (W, H))
+    draw = ImageDraw.Draw(im)
+    expected = "Tests/images/imagedraw_rectangle_width_fill.png"
+
+    # Act
+    draw.rounded_rectangle(BBOX1, 0, fill="blue", outline="green", width=5)
+
+    # Assert
+    assert_image_equal(im, Image.open(expected))
+
+
 def test_floodfill():
     red = ImageColor.getrgb("red")
 

docs/reference/ImageDraw.rst

@@ -285,6 +285,20 @@ Methods
 
         .. versionadded:: 5.3.0
 
+.. py:method:: ImageDraw.rounded_rectangle(xy, radius=0, fill=None, outline=None, width=1)
+
+    Draws a rounded rectangle.
+
+    :param xy: Two points to define the bounding box. Sequence of either
+            ``[(x0, y0), (x1, y1)]`` or ``[x0, y0, x1, y1]``. The second point
+            is just outside the drawn rectangle.
+    :param radius: Radius of the corners.
+    :param outline: Color to use for the outline.
+    :param fill: Color to use for the fill.
+    :param width: The line width, in pixels.
+
+        .. versionadded:: 8.2.0
+
 .. py:method:: ImageDraw.shape(shape, fill=None, outline=None)
 
     .. warning:: This method is experimental.

src/PIL/ImageDraw.py

@@ -257,6 +257,53 @@ def rectangle(self, xy, fill=None, outline=None, width=1):
         if ink is not None and ink != fill and width != 0:
             self.draw.draw_rectangle(xy, ink, 0, width)
 
+    def rounded_rectangle(self, xy, radius=0, fill=None, outline=None, width=1):
+        """Draw a rounded rectangle."""
+        if isinstance(xy[0], (list, tuple)):
+            (x0, y0), (x1, y1) = xy
+        else:
+            x0, y0, x1, y1 = xy
+
+        # Do not allow the diameter to be greater than the width or height
+        d = min(radius * 2, x1 - x0, y1 - y0)
+        if d == 0:
+            return self.rectangle(xy, fill, outline, width)
+
+        ink, fill = self._getink(outline, fill)
+        if fill is not None:
+            self.draw.draw_pieslice((x1 - d, y0, x1, y0 + d), 270, 360, fill, 1)
+            self.draw.draw_pieslice((x1 - d, y1 - d, x1, y1), 0, 90, fill, 1)
+            self.draw.draw_pieslice((x0, y1 - d, x0 + d, y1), 90, 180, fill, 1)
+            self.draw.draw_pieslice((x0, y0, x0 + d, y0 + d), 180, 270, fill, 1)
+
+            self.draw.draw_rectangle(
+                (x0 + d / 2 + 1, y0 + width, x1 - d / 2 - 1, y1 - width), fill, 1
+            )
+            self.draw.draw_rectangle(
+                (x0 + width, y0 + d / 2 + 1, x0 + d / 2, y1 - d / 2 - 1), fill, 1
+            )
+            self.draw.draw_rectangle(
+                (x1 - d / 2, y0 + d / 2 + 1, x1 - width, y1 - d / 2 - 1), fill, 1
+            )
+        if ink is not None and ink != fill and width != 0:
+            self.draw.draw_arc((x1 - d, y0, x1, y0 + d), 270, 360, ink, width)
+            self.draw.draw_arc((x1 - d, y1 - d, x1, y1), 0, 90, ink, width)
+            self.draw.draw_arc((x0, y1 - d, x0 + d, y1), 90, 180, ink, width)
+            self.draw.draw_arc((x0, y0, x0 + d, y0 + d), 180, 270, ink, width)
+
+            self.draw.draw_rectangle(
+                (x1 - width + 1, y0 + d / 2 + 1, x1, y1 - d / 2 - 1), ink, 1
+            )
+            self.draw.draw_rectangle(
+                (x0 + d / 2 + 1, y1 - width + 1, x1 - d / 2 - 1, y1), ink, 1
+            )
+            self.draw.draw_rectangle(
+                (x0, y0 + d / 2 + 1, x0 + width - 1, y1 - d / 2 - 1), ink, 1
+            )
+            self.draw.draw_rectangle(
+                (x0 + d / 2 + 1, y0, x1 - d / 2 - 1, y0 + width - 1), ink, 1
+            )
+
     def _multiline_check(self, text):
         """Draw text."""
         split_character = "\n" if isinstance(text, str) else b"\n"