Allow explicit zero width to hide outline

Tests/test_imagedraw.py

@@ -214,6 +214,18 @@ class TestImageDraw(PillowTestCase):
         # Assert
         self.assert_image_similar(im, Image.open(expected), 1)
 
+    def test_chord_zero_width(self):
+        # Arrange
+        im = Image.new("RGB", (W, H))
+        draw = ImageDraw.Draw(im)
+
+        # Act
+        draw.chord(BBOX1, 10, 260, fill="red", outline="yellow", width=0)
+
+        # Assert
+        with Image.open("Tests/images/imagedraw_chord_zero_width.png") as expected:
+            self.assert_image_equal(im, expected)
+
     def helper_ellipse(self, mode, bbox):
         # Arrange
         im = Image.new(mode, (W, H))
@@ -290,6 +302,18 @@ class TestImageDraw(PillowTestCase):
         # Assert
         self.assert_image_similar(im, Image.open(expected), 1)
 
+    def test_ellipse_zero_width(self):
+        # Arrange
+        im = Image.new("RGB", (W, H))
+        draw = ImageDraw.Draw(im)
+
+        # Act
+        draw.ellipse(BBOX1, fill="green", outline="blue", width=0)
+
+        # Assert
+        with Image.open("Tests/images/imagedraw_ellipse_zero_width.png") as expected:
+            self.assert_image_equal(im, expected)
+
     def helper_line(self, points):
         # Arrange
         im = Image.new("RGB", (W, H))
@@ -392,6 +416,18 @@ class TestImageDraw(PillowTestCase):
         # Assert
         self.assert_image_similar(im, Image.open(expected), 1)
 
+    def test_pieslice_zero_width(self):
+        # Arrange
+        im = Image.new("RGB", (W, H))
+        draw = ImageDraw.Draw(im)
+
+        # Act
+        draw.pieslice(BBOX1, 10, 260, fill="white", outline="blue", width=0)
+
+        # Assert
+        with Image.open("Tests/images/imagedraw_pieslice_zero_width.png") as expected:
+            self.assert_image_equal(im, expected)
+
     def helper_point(self, points):
         # Arrange
         im = Image.new("RGB", (W, H))
@@ -496,6 +532,18 @@ class TestImageDraw(PillowTestCase):
         # Assert
         self.assert_image_equal(im, Image.open(expected))
 
+    def test_rectangle_zero_width(self):
+        # Arrange
+        im = Image.new("RGB", (W, H))
+        draw = ImageDraw.Draw(im)
+
+        # Act
+        draw.rectangle(BBOX1, fill="blue", outline="green", width=0)
+
+        # Assert
+        with Image.open("Tests/images/imagedraw_rectangle_zero_width.png") as expected:
+            self.assert_image_equal(im, expected)
+
     def test_rectangle_I16(self):
         # Arrange
         im = Image.new("I;16", (W, H))

docs/reference/ImageDraw.rst

@@ -154,7 +154,7 @@ Methods
     To paste pixel data into an image, use the
     :py:meth:`~PIL.Image.Image.paste` method on the image itself.
 
-.. py:method:: PIL.ImageDraw.ImageDraw.chord(xy, start, end, fill=None, outline=None, width=0)
+.. py:method:: PIL.ImageDraw.ImageDraw.chord(xy, start, end, fill=None, outline=None, width=1)
 
     Same as :py:meth:`~PIL.ImageDraw.ImageDraw.arc`, but connects the end points
     with a straight line.
@@ -168,7 +168,7 @@ Methods
 
         .. versionadded:: 5.3.0
 
-.. py:method:: PIL.ImageDraw.ImageDraw.ellipse(xy, fill=None, outline=None, width=0)
+.. py:method:: PIL.ImageDraw.ImageDraw.ellipse(xy, fill=None, outline=None, width=1)
 
     Draws an ellipse inside the given bounding box.
 
@@ -198,7 +198,7 @@ Methods
 
         .. versionadded:: 5.3.0
 
-.. py:method:: PIL.ImageDraw.ImageDraw.pieslice(xy, start, end, fill=None, outline=None, width=0)
+.. py:method:: PIL.ImageDraw.ImageDraw.pieslice(xy, start, end, fill=None, outline=None, width=1)
 
     Same as arc, but also draws straight lines between the end points and the
     center of the bounding box.
@@ -236,7 +236,7 @@ Methods
     :param outline: Color to use for the outline.
     :param fill: Color to use for the fill.
 
-.. py:method:: PIL.ImageDraw.ImageDraw.rectangle(xy, fill=None, outline=None, width=0)
+.. py:method:: PIL.ImageDraw.ImageDraw.rectangle(xy, fill=None, outline=None, width=1)
 
     Draws a rectangle.
 

src/PIL/ImageDraw.py

@@ -134,20 +134,20 @@ class ImageDraw:
         if ink is not None:
             self.draw.draw_bitmap(xy, bitmap.im, ink)
 
-    def chord(self, xy, start, end, fill=None, outline=None, width=0):
+    def chord(self, xy, start, end, fill=None, outline=None, width=1):
         """Draw a chord."""
         ink, fill = self._getink(outline, fill)
         if fill is not None:
             self.draw.draw_chord(xy, start, end, fill, 1)
-        if ink is not None and ink != fill:
+        if ink is not None and ink != fill and width != 0:
             self.draw.draw_chord(xy, start, end, ink, 0, width)
 
-    def ellipse(self, xy, fill=None, outline=None, width=0):
+    def ellipse(self, xy, fill=None, outline=None, width=1):
         """Draw an ellipse."""
         ink, fill = self._getink(outline, fill)
         if fill is not None:
             self.draw.draw_ellipse(xy, fill, 1)
-        if ink is not None and ink != fill:
+        if ink is not None and ink != fill and width != 0:
             self.draw.draw_ellipse(xy, ink, 0, width)
 
     def line(self, xy, fill=None, width=0, joint=None):
@@ -219,12 +219,12 @@ class ImageDraw:
         if ink is not None and ink != fill:
             self.draw.draw_outline(shape, ink, 0)
 
-    def pieslice(self, xy, start, end, fill=None, outline=None, width=0):
+    def pieslice(self, xy, start, end, fill=None, outline=None, width=1):
         """Draw a pieslice."""
         ink, fill = self._getink(outline, fill)
         if fill is not None:
             self.draw.draw_pieslice(xy, start, end, fill, 1)
-        if ink is not None and ink != fill:
+        if ink is not None and ink != fill and width != 0:
             self.draw.draw_pieslice(xy, start, end, ink, 0, width)
 
     def point(self, xy, fill=None):
@@ -241,12 +241,12 @@ class ImageDraw:
         if ink is not None and ink != fill:
             self.draw.draw_polygon(xy, ink, 0)
 
-    def rectangle(self, xy, fill=None, outline=None, width=0):
+    def rectangle(self, xy, fill=None, outline=None, width=1):
         """Draw a rectangle."""
         ink, fill = self._getink(outline, fill)
         if fill is not None:
             self.draw.draw_rectangle(xy, fill, 1)
-        if ink is not None and ink != fill:
+        if ink is not None and ink != fill and width != 0:
             self.draw.draw_rectangle(xy, ink, 0, width)
 
     def _multiline_check(self, text):