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Transparency conversion for L, RGP and P images, fixes #510

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wiredfool 2014-03-25 23:34:41 -07:00
parent 89c24e971c
commit 8ea903ec59
1 changed files with 53 additions and 6 deletions
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59
PIL/Image.py
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@ -738,21 +738,62 @@ class Image:
if mode == "P" and self.mode == "RGBA":
return self.quantize(colors)
trns = None
delete_trns = False
# transparency handling
if "transparency" in self.info and self.info['transparency'] is not None:
if self.mode in ('L', 'RGB') and mode == 'RGBA':
# Use transparent conversion to promote from transparent
# color to an alpha channel.
return self._new(self.im.convert_transparent(
mode, self.info['transparency']))
elif self.mode in ('L', 'RGB', 'P') and mode in ('L', 'RGB', 'P'):
t = self.info['transparency']
if isinstance(t, bytes):
# Dragons. This can't be represented by a single color
warnings.warn('Palette images with Transparency expressed '+
' in bytes should be converted to RGBA images')
delete_trns = True
else:
# get the new transparency color.
# use existing conversions
trns_im = Image()._new(core.new(self.mode, (1,1)))
if self.mode == 'P':
trns_im.putpalette(self.palette)
trns_im.putpixel((0,0), t)
if mode in ('L','RGB'):
trns_im = trns_im.convert(mode)
else:
# can't just retrieve the palette number, got to do it
# after quantization.
trns_im = trns_im.convert('RGB')
trns = trns_im.getpixel((0,0))
if mode == "P" and palette == ADAPTIVE:
im = self.im.quantize(colors)
new = self._new(im)
from PIL import ImagePalette
new.palette = ImagePalette.raw("RGB", new.im.getpalette("RGB"))
if delete_trns:
# This could possibly happen if we requantize to fewer colors.
# The transparency would be totally off in that case.
del(new.info['transparency'])
if trns is not None:
try:
new.info['transparency'] = new.palette.getcolor(trns)
except:
# if we can't make a transparent color, don't leave the old
# transparency hanging around to mess us up.
del(new.info['transparency'])
warnings.warn("Couldn't allocate palette entry for transparency")
return new
# colorspace conversion
if dither is None:
dither = FLOYDSTEINBERG
# Use transparent conversion to promote from transparent color to an alpha channel.
if self.mode in ("L", "RGB") and mode == "RGBA" and "transparency" in self.info:
return self._new(self.im.convert_transparent(mode, self.info['transparency']))
try:
im = self.im.convert(mode, dither)
except ValueError:
@ -763,7 +804,13 @@ class Image:
except KeyError:
raise ValueError("illegal conversion")
return self._new(im)
new_im = self._new(im)
if delete_trns:
#crash fail if we leave a bytes transparency in an rgb/l mode.
del(new.info['transparency'])
if trns is not None:
new_im.info['transparency'] = trns
return new_im
def quantize(self, colors=256, method=None, kmeans=0, palette=None):