MSS: fix save_img() on Windows 8.1

BoboTiG · BoboTiG · commit d70708985e75 · 2015-04-16T15:50:46.000+02:00
diff --git a/mss.py b/mss.py
@@ -11,7 +11,7 @@
     If that URL should fail, try contacting the author.
 '''
 
-from __future__ import unicode_literals, print_function, division
+from __future__ import division, print_function, unicode_literals
 
 __version__ = '1.0.0'
 __author__ = "Mickaël 'Tiger-222' Schoentgen"
@@ -190,31 +190,33 @@ def save_img(self, data, width, height, output):
             http://inaps.org/journal/comment-fonctionne-le-png
         '''
 
-        zcrc32 = crc32
-        zcompr = compress
-        len_sl = width * 3
+        len_sl = (width * 3 + 3) & -4
+        padding = 0 if len_sl % 8 == 0 else (len_sl % 8) // 2
         scanlines = b''.join(
-            [b'0' + data[y * len_sl:y * len_sl + len_sl]
+            [b'0' + data[y * len_sl:y * len_sl + len_sl - padding]
              for y in range(height)])
+        zcrc32 = crc32
+        zcompr = compress
+        b = pack
 
-        magic = pack(b'>8B', 137, 80, 78, 71, 13, 10, 26, 10)
+        magic = b(b'>8B', 137, 80, 78, 71, 13, 10, 26, 10)
 
         # Header: size, marker, data, CRC32
         ihdr = [b'', b'IHDR', b'', b'']
-        ihdr[2] = pack(b'>2I5B', width, height, 8, 2, 0, 0, 0)
-        ihdr[3] = pack(b'>I', zcrc32(b''.join(ihdr[1:3])) & 0xffffffff)
-        ihdr[0] = pack(b'>I', len(ihdr[2]))
+        ihdr[2] = b(b'>2I5B', width, height, 8, 2, 0, 0, 0)
+        ihdr[3] = b(b'>I', zcrc32(b''.join(ihdr[1:3])) & 0xffffffff)
+        ihdr[0] = b(b'>I', len(ihdr[2]))
 
         # Data: size, marker, data, CRC32
         idat = [b'', b'IDAT', b'', b'']
         idat[2] = zcompr(scanlines, 9)
-        idat[3] = pack(b'>I', zcrc32(b''.join(idat[1:3])) & 0xffffffff)
-        idat[0] = pack(b'>I', len(idat[2]))
+        idat[3] = b(b'>I', zcrc32(b''.join(idat[1:3])) & 0xffffffff)
+        idat[0] = b(b'>I', len(idat[2]))
 
         # Footer: size, marker, None, CRC32
         iend = [b'', b'IEND', b'', b'']
-        iend[3] = pack(b'>I', zcrc32(iend[1]) & 0xffffffff)
-        iend[0] = pack(b'>I', len(iend[2]))
+        iend[3] = b(b'>I', zcrc32(iend[1]) & 0xffffffff)
+        iend[0] = b(b'>I', len(iend[2]))
 
         with open(output, 'wb') as fileh:
             fileh.write(
