#!/usr/bin/python3
import PIL
+import PIL.ImageFilter
import difflib
import io
import logging
return thumbnail
- def _generate_thumbnail(self, size):
+ def _generate_thumbnail(self, size, **args):
image = PIL.Image.open(io.BytesIO(self.blob))
+ # Remove any alpha-channels
+ if image.format == "JPEG" and not image.mode == "RGB":
+ # Make a white background
+ background = PIL.Image.new("RGBA", image.size, (255,255,255))
+
+ # Flatten both images together
+ flattened_image = PIL.Image.alpha_composite(background, image)
+
+ # Remove the alpha channel
+ image = flattened_image.convert("RGB")
+
# Resize the image to the desired resolution
- image.thumbnail((size, size), PIL.Image.ANTIALIAS)
+ image.thumbnail((size, size), PIL.Image.LANCZOS)
+
+ if image.format == "JPEG":
+ # Apply a gaussian blur to make compression easier
+ image = image.filter(PIL.ImageFilter.GaussianBlur(radius=0.05))
+
+ # Arguments to optimise the compression
+ args.update({
+ "subsampling" : "4:2:0",
+ "quality" : 70,
+ })
with io.BytesIO() as f:
# If writing out the image does not work with optimization,
# we try to write it out without any optimization.
try:
- image.save(f, image.format, optimize=True, quality=98)
+ image.save(f, image.format, optimize=True, **args)
except:
- image.save(f, image.format, quality=98)
+ image.save(f, image.format, **args)
return f.getvalue()