Allow RGBA value for P image putpixel

Tests/test_image_access.py

@@ -175,10 +175,11 @@ class TestImageGetPixel(AccessTest):
             self.check(mode, 2**15+1)
             self.check(mode, 2**16-1)
 
-    def test_p_putpixel_rgb(self):
-        im = Image.new("P", (1, 1), 0)
-        im.putpixel((0, 0), (255, 0, 0))
-        self.assertEqual(im.convert("RGB").getpixel((0, 0)), (255, 0, 0))
+    def test_p_putpixel_rgb_rgba(self):
+        for color in [(255, 0, 0), (255, 0, 0, 255)]:
+            im = Image.new("P", (1, 1), 0)
+            im.putpixel((0, 0), color)
+            self.assertEqual(im.convert("RGB").getpixel((0, 0)), (255, 0, 0))
 
 
 @unittest.skipIf(cffi is None, "No cffi")
@@ -299,11 +300,12 @@ class TestCffi(AccessTest):
                 # pixels can contain garbage if image is released
                 self.assertEqual(px[i, 0], 0)
 
-    def test_p_putpixel_rgb(self):
-        im = Image.new("P", (1, 1), 0)
-        access = PyAccess.new(im, False)
-        access.putpixel((0, 0), (255, 0, 0))
-        self.assertEqual(im.convert("RGB").getpixel((0, 0)), (255, 0, 0))
+    def test_p_putpixel_rgb_rgba(self):
+        for color in [(255, 0, 0), (255, 0, 0, 255)]:
+            im = Image.new("P", (1, 1), 0)
+            access = PyAccess.new(im, False)
+            access.putpixel((0, 0), color)
+            self.assertEqual(im.convert("RGB").getpixel((0, 0)), (255, 0, 0))
 
 
 class TestEmbeddable(unittest.TestCase):

docs/reference/PixelAccess.rst

@@ -65,8 +65,8 @@ Access using negative indexes is also possible.
 
         Modifies the pixel at x,y. The color is given as a single
         numerical value for single band images, and a tuple for
-        multi-band images. In addition to this, RGB tuples are accepted
-        for P images.
+        multi-band images. In addition to this, RGB and RGBA tuples
+        are accepted for P images.
 
         :param xy: The pixel coordinate, given as (x, y).
         :param color: The pixel value according to its mode. e.g. tuple (r, g, b) for RGB mode)

src/PIL/Image.py

@@ -1651,8 +1651,8 @@ class Image(object):
         """
         Modifies the pixel at the given position. The color is given as
         a single numerical value for single-band images, and a tuple for
-        multi-band images. In addition to this, RGB tuples are accepted
-        for P images.
+        multi-band images. In addition to this, RGB and RGBA tuples are
+        accepted for P images.
 
         Note that this method is relatively slow.  For more extensive changes,
         use :py:meth:`~PIL.Image.Image.paste` or the :py:mod:`~PIL.ImageDraw`
@@ -1677,8 +1677,8 @@ class Image(object):
             return self.pyaccess.putpixel(xy, value)
 
         if self.mode == "P" and \
-           isinstance(value, (list, tuple)) and len(value) == 3:
-            # RGB value for a P image
+           isinstance(value, (list, tuple)) and len(value) in [3, 4]:
+            # RGB or RGBA value for a P image
             value = self.palette.getcolor(value)
         return self.im.putpixel(xy, value)
 

src/PIL/PyAccess.py

@@ -84,8 +84,8 @@ class PyAccess(object):
         (x, y) = self.check_xy((x, y))
 
         if self._im.mode == "P" and \
-           isinstance(color, (list, tuple)) and len(color) == 3:
-            # RGB value for a P image
+           isinstance(color, (list, tuple)) and len(color) in [3, 4]:
+            # RGB or RGBA value for a P image
             color = self._palette.getcolor(color)
 
         return self.set_pixel(x, y, color)