Test for drawing mask contour on a transparent background.

test/test_wordcloud.py

@@ -1,4 +1,5 @@
 from wordcloud import WordCloud, get_single_color_func, ImageColorGenerator
+import os
 import numpy as np
 from random import Random
 from nose.tools import (assert_equal, assert_greater, assert_true, assert_false,
@@ -229,6 +230,18 @@ def test_mask_contour():
     assert_true(all(sm_array[100, 300] == [0, 0, 255]))
 
 
+def test_test_mask_contour_transparent():
+    # test if mask contour can be drawn on a transparent background
+    # https://github.com/amueller/word_cloud/pull/389
+    examples_dir = os.path.realpath(os.path.join(os.path.dirname(__file__), '..', 'examples'))
+    mask_file = os.path.join(examples_dir, 'alice_mask.png')
+    mask = np.array(Image.open(mask_file))
+    w = WordCloud(mode='RGBA', background_color=None, contour_color='blue', contour_width=2, mask=mask,
+                  max_words=50, width=800, height=800)
+    w.generate(THIS)
+    w.to_file(NamedTemporaryFile(suffix=".png").name)
+
+
 def test_single_color_func():
     # test single color function for different color formats
     random = Random(42)