Issue 5588: fix color-profile warning in output-distance (issue 545100043 by address@hidden)

[nine . fierce . ballads]

Reviewers: ,

Description:
https://sourceforge.net/p/testlilyissues/issues/5588/

The warning is "RGB color space not permitted on grayscale PNG" and the
solution is to strip the profile from the image.

Please review this at https://codereview.appspot.com/545100043/

Affected files (+4, -2 lines):
  M scripts/build/output-distance.py


Index: scripts/build/output-distance.py
diff --git a/scripts/build/output-distance.py  
b/scripts/build/output-distance.py
index  
395fa65a6d6cb11105efb502a861816565884df8..5cf1def9af4a09b245add9d0caa6cf0d6958bc7a  
100755
--- a/scripts/build/output-distance.py
+++ b/scripts/build/output-distance.py
@@ -94,8 +94,10 @@ def compare_png_images (old, new, dest_dir):
             min (dims1[1], dims2[1]))

     dir = get_temp_dir ()
-    system ('convert -depth 8 -crop %dx%d+0+0 %s %s/crop1.png' % (dims +  
(old, dir)))
-    system ('convert -depth 8 -crop %dx%d+0+0 %s %s/crop2.png' % (dims +  
(new, dir)))
+    # "+profile icc" strips the ICC profile, which suppresses the
+    # warning "RGB color space not permitted on grayscale PNG."
+    system ('convert +profile icc -depth 8  
-crop %dx%d+0+0 %s %s/crop1.png' % (dims + (old, dir)))
+    system ('convert +profile icc -depth 8  
-crop %dx%d+0+0 %s %s/crop2.png' % (dims + (new, dir)))

     system1 ('compare -depth 8 -dissimilarity-threshold  
1 %(dir)s/crop1.png %(dir)s/crop2.png %(dir)s/diff.png' % locals ())