Use the appropriate PNG rendered given the types of image present

2015-02-11 03:32:00 -08:00
parent f7db8d9aff
commit 638c6db05d
1 changed files with 9 additions and 1 deletions
@@ -308,12 +308,20 @@ def convert_to_png(input_file, output_file):
 def unpack_with_ghostscript(
        input_file,
        output_file):
+    device = 'png16m'  # 24-bit
+    if all(image['comp'] == 1 for image in pageinfo['images']):
+        if all(image['bpc'] == 1 for image in pageinfo['images']):
+            device = 'pngmono'
+        elif not any(image['color'] == 'color'
+                     for image in pageinfo['images']):
+            device = 'pnggray'
+
    args_gs = [
        'gs',
        '-dBATCH', '-dNOPAUSE',
        '-dFirstPage=%i' % pageno,
        '-dLastPage=%i' % pageno,
-        '-sDEVICE=pngalpha',
+        '-sDEVICE=%s' % device,
        '-o', output_file,
        '-r{0}x{1}'.format(str(pageinfo['xres']), str(pageinfo['yres'])),
        input_file