Merge pull request #574 from wiredfool/convert_trns

Indexed Transparency handled for conversions between L, RGB, and P modes
This commit is contained in:
wiredfool 2014-03-31 21:40:22 -07:00
commit 6e2075e25d
5 changed files with 151 additions and 10 deletions

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@ -4,6 +4,12 @@ Changelog (Pillow)
2.4.0 (unreleased)
------------------
- Indexed Transparency handled for conversions between L, RGB, and P modes. Fixes #510
[wiredfool]
- Conversions enabled from RGBA->P, Fixes #544
[wiredfool]
- Improved icns support
[al45tair]

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@ -735,21 +735,65 @@ class Image:
im = self.im.convert_matrix(mode, matrix)
return self._new(im)
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:
@ -760,9 +804,22 @@ 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:
if new_im.mode == 'P':
try:
new_im.info['transparency'] = new_im.palette.getcolor(trns)
except:
del(new_im.info['transparency'])
warnings.warn("Couldn't allocate palette entry for transparency")
else:
new_im.info['transparency'] = trns
return new_im
def quantize(self, colors=256, method=0, kmeans=0, palette=None):
def quantize(self, colors=256, method=None, kmeans=0, palette=None):
# methods:
# 0 = median cut
@ -773,7 +830,18 @@ class Image:
# quantizer interface in a later version of PIL.
self.load()
if method is None:
# defaults:
method = 0
if self.mode == 'RGBA':
method = 2
if self.mode == 'RGBA' and method != 2:
# Caller specified an invalid mode.
raise ValueError('Fast Octree (method == 2) is the ' +
' only valid method for quantizing RGBA images')
if palette:
# use palette from reference image
palette.load()

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@ -46,5 +46,67 @@ def test_16bit_workaround():
im = Image.open('Tests/images/16bit.cropped.tif')
_test_float_conversion(im.convert('I'))
def test_rgba_p():
im = lena('RGBA')
im.putalpha(lena('L'))
converted = im.convert('P')
comparable = converted.convert('RGBA')
assert_image_similar(im, comparable, 20)
def test_trns_p():
im = lena('P')
im.info['transparency']=0
f = tempfile('temp.png')
l = im.convert('L')
assert_equal(l.info['transparency'], 0) # undone
assert_no_exception(lambda: l.save(f))
rgb = im.convert('RGB')
assert_equal(rgb.info['transparency'], (0,0,0)) # undone
assert_no_exception(lambda: rgb.save(f))
def test_trns_l():
im = lena('L')
im.info['transparency'] = 128
f = tempfile('temp.png')
rgb = im.convert('RGB')
assert_equal(rgb.info['transparency'], (128,128,128)) # undone
assert_no_exception(lambda: rgb.save(f))
p = im.convert('P')
assert_true('transparency' in p.info)
assert_no_exception(lambda: p.save(f))
p = assert_warning(UserWarning,
lambda: im.convert('P', palette = Image.ADAPTIVE))
assert_false('transparency' in p.info)
assert_no_exception(lambda: p.save(f))
def test_trns_RGB():
im = lena('RGB')
im.info['transparency'] = im.getpixel((0,0))
f = tempfile('temp.png')
l = im.convert('L')
assert_equal(l.info['transparency'], l.getpixel((0,0))) # undone
assert_no_exception(lambda: l.save(f))
p = im.convert('P')
assert_true('transparency' in p.info)
assert_no_exception(lambda: p.save(f))
p = assert_warning(UserWarning,
lambda: im.convert('P', palette = Image.ADAPTIVE))
assert_false('transparency' in p.info)
assert_no_exception(lambda: p.save(f))

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@ -19,4 +19,9 @@ def test_octree_quantize():
im = im.quantize(100, Image.FASTOCTREE)
assert_image(im, "P", im.size)
assert len(im.getcolors()) == 100
assert len(im.getcolors()) == 100
def test_rgba_quantize():
im = lena('RGBA')
assert_no_exception(lambda: im.quantize())
assert_exception(Exception, lambda: im.quantize(method=0))

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@ -121,9 +121,9 @@ def assert_no_exception(func):
def assert_warning(warn_class, func):
# note: this assert calls func three times!
import warnings
def warn_error(message, category, **options):
def warn_error(message, category=UserWarning, **options):
raise category(message)
def warn_ignore(message, category, **options):
def warn_ignore(message, category=UserWarning, **options):
pass
warn = warnings.warn
result = None