def quantize(img, colors=256, alpha=False, defaults=None, quantizer=None):
if hasattr(Image, 'FASTOCTREE') and quantizer in (None, 'fastoctree'):
if not alpha:
img = img.convert('RGB')
try:
img = img.quantize(colors, Image.FASTOCTREE)
except ValueError:
pass
else:
if alpha and img.mode == 'RGBA':
img.load() # split might fail if image is not loaded
alpha = img.split()[3]
img = img.convert('RGB').convert('P',
palette=Image.ADAPTIVE,
colors=colors - 1)
mask = Image.eval(alpha, lambda a: 255 if a <= 128 else 0)
img.paste(255, mask)
if defaults is not None:
defaults['transparency'] = 255
else:
img = img.convert('RGB').convert('P',
palette=Image.ADAPTIVE,
colors=colors)
return img
def _make_transparent(img, color, tolerance=10):
img.load()
if img.mode == 'P':
img = img.convert('RGBA')
channels = img.split()
mask_channels = []
for ch, c in zip(channels, color):
# create bit mask for each matched color
low_c, high_c = c - tolerance, c + tolerance
mask_channels.append(
Image.eval(ch, lambda x: 255 if low_c <= x <= high_c else 0))
# multiply channel bit masks to get a single mask
alpha = reduce(ImageChops.multiply, mask_channels)
# invert to get alpha channel
alpha = ImageChops.invert(alpha)
if len(channels) == 4:
# multiply with existing alpha
alpha = ImageChops.multiply(alpha, channels[-1])
img.putalpha(alpha)
return img
def quantize(img, colors=256, alpha=False, defaults=None, quantizer=None):
if hasattr(Image, 'FASTOCTREE') and quantizer in (None, 'fastoctree'):
if not alpha:
img = img.convert('RGB')
img = img.quantize(colors, Image.FASTOCTREE)
else:
if alpha and img.mode == 'RGBA':
img.load() # split might fail if image is not loaded
alpha = img.split()[3]
img = img.convert('RGB').convert('P', palette=Image.ADAPTIVE, colors=colors-1)
mask = Image.eval(alpha, lambda a: 255 if a <=128 else 0)
img.paste(255, mask)
if defaults is not None:
defaults['transparency'] = 255
else:
img = img.convert('RGB').convert('P', palette=Image.ADAPTIVE, colors=colors)
return img
def _make_transparent(img, color, tolerance=10):
img.load()
if img.mode == 'P':
img = img.convert('RGBA')
channels = img.split()
mask_channels = []
for ch, c in zip(channels, color):
# create bit mask for each matched color
low_c, high_c = c-tolerance, c+tolerance
mask_channels.append(Image.eval(ch, lambda x: 255 if low_c <= x <= high_c else 0))
# multiply channel bit masks to get a single mask
alpha = reduce(ImageChops.multiply, mask_channels)
# invert to get alpha channel
alpha = ImageChops.invert(alpha)
if len(channels) == 4:
# multiply with existing alpha
alpha = ImageChops.multiply(alpha, channels[-1])
img.putalpha(alpha)
return img
