misc: write down license and author in the png files

wcs/qommon/static/images/categories/generate.py

@@ -4,6 +4,9 @@ from optparse import OptionParser
 import subprocess
 import tempfile
 import xml.etree.ElementTree as ET
+import re
+from PIL import Image
+from PIL import PngImagePlugin
 
 mapping = {
     '207': 'trash',
@@ -53,3 +56,20 @@ for icon_id, icon_name in mapping.items():
         '--file', svg_path,
         '--export-png', output_filename,
         '--export-width', '42'])
+
+    # write down licensing info in the png file
+    meta = PngImagePlugin.PngInfo()
+    license_txt = open('src/icon_%s/license.txt' % icon_id).read()
+    try:
+        meta.add_text('Author', re.findall('by(.*)', license_txt)[0], 0)
+    except IndexError:
+        pass
+    license_txt = license_txt.replace('\n', ' ')
+    for license in ['Public Domain', 'Creative Commons Attribution']:
+        if license in license_txt:
+            meta.add_text('Licence', license, 0)
+            break
+    else:
+        print >> sys.stderr, 'Warning: no license known for', svg_path
+    png_file = Image.open(output_filename)
+    png_file.save(output_filename, "PNG", pnginfo=meta)