Implement PNG optimizer with pillow

overviewer_core/optimizeimages.py

@@ -15,6 +15,7 @@
 
 import os
 import subprocess
+from PIL import Image
 
 
 class Optimizer:
@@ -209,6 +210,27 @@ def is_crusher(self):
         return True
 
 
+class pillowpng(Optimizer, PNGOptimizer):
+
+    def __init__(self, colors=256, dither=True):
+        if colors < 2:
+            raise Exception("You can't use less than 2 colors")
+        self.colors = colors
+        self.dither = dither
+
+    def optimize(self, img):
+        orig = Image.open(img)
+        conv = orig.convert('P', palette=Image.ADAPTIVE, colors=self.colors,
+                            dither=Image.FLOYDSTEINBERG if self.dither else Image.NONE)
+        conv.save(img, format='PNG', optimize=True)
+
+    def check_availability(self):
+        return True
+
+    def is_crusher(self):
+        return True
+
+
 def optimize_image(imgpath, imgformat, optimizers):
     for opt in optimizers:
         if imgformat == 'png':

overviewer_core/settingsDefinition.py

@@ -47,7 +47,7 @@
 
 from .settingsValidators import *
 from .observer import ProgressBarObserver, LoggingObserver, JSObserver
-from .optimizeimages import pngnq, optipng, pngcrush
+from .optimizeimages import pngnq, optipng, pngcrush, pillowpng
 import platform
 import sys