Get background color from savefig.facecolor

mdboom · mdboom · commit 3dea66d9e591 · 2015-10-27T12:41:43.000-04:00
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -38,6 +38,7 @@
 from matplotlib.mathtext import MathTextParser
 from matplotlib.path import Path
 from matplotlib.transforms import Bbox, BboxBase
+from matplotlib import colors as mcolors
 
 from matplotlib.backends._backend_agg import RendererAgg as _RendererAgg
 from matplotlib import _png
@@ -575,7 +576,10 @@ def print_jpg(self, filename_or_obj, *args, **kwargs):
             # The image is "pasted" onto a white background image to safely
             # handle any transparency
             image = Image.frombuffer('RGBA', size, buf, 'raw', 'RGBA', 0, 1)
-            background = Image.new('RGB', size, (255, 255, 255))
+            color = mcolors.colorConverter.to_rgb(
+                rcParams.get('savefig.facecolor', 'white'))
+            color = tuple([int(x * 255.0) for x in color])
+            background = Image.new('RGB', size, color)
             background.paste(image, image)
             options = restrict_dict(kwargs, ['quality', 'optimize',
                                              'progressive'])
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -8,7 +8,7 @@
 from matplotlib.testing.decorators import image_comparison, knownfailureif, cleanup
 from matplotlib.image import BboxImage, imread, NonUniformImage
 from matplotlib.transforms import Bbox
-from matplotlib import rcParams
+from matplotlib import rcParams, rc_context
 import matplotlib.pyplot as plt
 from nose.tools import assert_raises
 from numpy.testing import assert_array_equal, assert_array_almost_equal
@@ -465,14 +465,18 @@ def test_jpeg_alpha():
     plt.figimage(im)
 
     buff = io.BytesIO()
-    plt.savefig(buff, transparent=True, format='jpg', dpi=300)
+    with rc_context({'savefig.facecolor': 'red'}):
+        plt.savefig(buff, transparent=True, format='jpg', dpi=300)
 
     buff.seek(0)
     image = Image.open(buff)
 
     # If this fails, there will be only one color (all black). If this
     # is working, we should have all 256 shades of grey represented.
-    assert len(image.getcolors(256)) == 256
+    assert len(image.getcolors(256)) == 179
+    # The fully transparent part should be red, not white or black
+    # or anything else
+    assert image.getpixel(0, 0) == (0, 0, 255)
 
 
 if __name__=='__main__':
