Add a feature to ImageDraw.text() to stroke text

PIL/ImageDraw.py

@@ -217,12 +217,11 @@ def _multiline_split(self, text):
 
         return text.split(split_character)
 
-    def text(self, xy, text, fill=None, font=None, anchor=None,
-             *args, **kwargs):
+    def text(self, xy, text, fill=None, font=None, anchor=None, spacing=4, 
+             align="left", outline=None):
         if self._multiline_check(text):
             return self.multiline_text(xy, text, fill, font, anchor,
-                                       *args, **kwargs)
-
+                                       spacing, align, outline)
         ink, fill = self._getink(fill)
         if font is None:
             font = self.getfont()
@@ -237,10 +236,17 @@ def text(self, xy, text, fill=None, font=None, anchor=None,
                     mask = font.getmask(text, self.fontmode)
                 except TypeError:
                     mask = font.getmask(text)
+            if outline is not None:
+                color, _ = self._getink(outline)
+                for offset in range(0, 2):
+                    tmp_xy = list(xy)
+                    for difference in [-1, 1]:
+                        tmp_xy[offset] = xy[offset] + difference
+                        self.draw.draw_bitmap(tmp_xy, mask, color)
             self.draw.draw_bitmap(xy, mask, ink)
 
     def multiline_text(self, xy, text, fill=None, font=None, anchor=None,
-                       spacing=4, align="left"):
+                       spacing=4, align="left", outline=None):
         widths = []
         max_width = 0
         lines = self._multiline_split(text)
@@ -259,10 +265,9 @@ def multiline_text(self, xy, text, fill=None, font=None, anchor=None,
                 left += (max_width - widths[idx])
             else:
                 assert False, 'align must be "left", "center" or "right"'
-            self.text((left, top), line, fill, font, anchor)
+            self.text((left, top), line, fill, font, anchor, outline=outline)
             top += line_spacing
             left = xy[0]
-
     def textsize(self, text, font=None, *args, **kwargs):
         """Get the size of a given string, in pixels."""
         if self._multiline_check(text):

Tests/test_imagefont.py

@@ -127,6 +127,18 @@ def test_textsize_equal(self):
             target_img = Image.open(target)
             self.assert_image_similar(im, target_img, .5)
 
+        def test_stroke_text(self):
+            im = Image.new(mode='RGB', size=(300, 100))
+            draw = ImageDraw.Draw(im)
+            ttf = ImageFont.truetype(FONT_PATH, FONT_SIZE)
+
+            draw.text((5, 5), TEST_TEXT, 'black', font=ttf,
+                      outline='white')
+
+            target = 'Tests/images/stroked_text_image.png'
+            target_img = Image.open(target)
+            self.assert_image_similar(im, target_img, .5)
+
         def test_render_multiline(self):
             im = Image.new(mode='RGB', size=(300, 100))
             draw = ImageDraw.Draw(im)

docs/reference/ImageDraw.rst

@@ -240,6 +240,7 @@ Methods
                     the number of pixels between lines.
     :param align: If the text is passed on to multiline_text(),
                   "left", "center" or "right".
+    :param outline: Color to use to draw an outline around the text.
 
 
 .. py:method:: PIL.ImageDraw.Draw.multiline_text(xy, text, fill=None, font=None, anchor=None, spacing=0, align="left")
@@ -252,6 +253,7 @@ Methods
     :param font: An :py:class:`~PIL.ImageFont.ImageFont` instance.
     :param spacing: The number of pixels between lines.
     :param align: "left", "center" or "right".
+    :param outline: Color to use to draw an outline around the text.
 
 .. py:method:: PIL.ImageDraw.Draw.textsize(text, font=None, spacing=0)
 

docs/releasenotes/3.5.0.rst

@@ -0,0 +1,10 @@
+3.5.0
+-----
+
+New text-outlining feature
+==========================
+
+Both ``ImageDraw.text()`` and ``ImageDraw.multiline_text()`` now supports
+text-stroking.
+Passing in a color value to the methods using the ``outline`` keyword argument
+will now outline the text in that color.

docs/releasenotes/index.rst

@@ -6,6 +6,7 @@ Release Notes
 .. toctree::
   :maxdepth: 2
 
+  3.5.0
   3.4.0
   3.3.2
   3.3.0