Pillow/PIL/ImagePalette.py
David Schmidt 93a8bc9bd3 * fix palette handling for converted gifs
* fix gif optimization
* better auto convert paramter for gif save
2014-03-04 21:44:32 -08:00

207 lines
5.7 KiB
Python

#
# The Python Imaging Library.
# $Id$
#
# image palette object
#
# History:
# 1996-03-11 fl Rewritten.
# 1997-01-03 fl Up and running.
# 1997-08-23 fl Added load hack
# 2001-04-16 fl Fixed randint shadow bug in random()
#
# Copyright (c) 1997-2001 by Secret Labs AB
# Copyright (c) 1996-1997 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#
import array
from PIL import Image, ImageColor
class ImagePalette:
"Color palette for palette mapped images"
def __init__(self, mode = "RGB", palette = None, size = 0):
self.mode = mode
self.rawmode = None # if set, palette contains raw data
self.palette = palette or list(range(256))*len(self.mode)
self.colors = {}
self.dirty = None
if ((size == 0 and len(self.mode)*256 != len(self.palette)) or
(size != 0 and size != len(self.palette))):
raise ValueError("wrong palette size")
def getdata(self):
"""
Get palette contents in format suitable # for the low-level
``im.putpalette`` primitive.
.. warning:: This method is experimental.
"""
if self.rawmode:
return self.rawmode, self.palette
return self.mode + ";L", self.tobytes()
def tobytes(self):
"""Convert palette to bytes.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(self.palette, bytes):
return self.palette
arr = array.array("B", self.palette)
if hasattr(arr, 'tobytes'):
#py3k has a tobytes, tostring is deprecated.
return arr.tobytes()
return arr.tostring()
# Declare tostring as an alias for tobytes
tostring = tobytes
def getcolor(self, color):
"""Given an rgb tuple, allocate palette entry.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(color, tuple):
try:
return self.colors[color]
except KeyError:
# allocate new color slot
if isinstance(self.palette, bytes):
self.palette = [int(x) for x in self.palette]
index = len(self.colors)
if index >= 256:
raise ValueError("cannot allocate more than 256 colors")
self.colors[color] = index
self.palette[index] = color[0]
self.palette[index+256] = color[1]
self.palette[index+512] = color[2]
self.dirty = 1
return index
else:
raise ValueError("unknown color specifier: %r" % color)
def save(self, fp):
"""Save palette to text file.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(fp, str):
fp = open(fp, "w")
fp.write("# Palette\n")
fp.write("# Mode: %s\n" % self.mode)
for i in range(256):
fp.write("%d" % i)
for j in range(i, len(self.palette), 256):
fp.write(" %d" % self.palette[j])
fp.write("\n")
fp.close()
# --------------------------------------------------------------------
# Internal
def raw(rawmode, data):
palette = ImagePalette()
palette.rawmode = rawmode
palette.palette = data
palette.dirty = 1
return palette
# --------------------------------------------------------------------
# Factories
def _make_linear_lut(black, white):
lut = []
if black == 0:
for i in range(256):
lut.append(white*i//255)
else:
raise NotImplementedError # FIXME
return lut
def _make_gamma_lut(exp, mode="RGB"):
lut = []
for i in range(256):
lut.append(int(((i / 255.0) ** exp) * 255.0 + 0.5))
return lut
def new(mode, data):
return Image.core.new_palette(mode, data)
def negative(mode="RGB"):
palette = list(range(256))
palette.reverse()
return ImagePalette(mode, palette * len(mode))
def random(mode="RGB"):
from random import randint
palette = []
for i in range(256*len(mode)):
palette.append(randint(0, 255))
return ImagePalette(mode, palette)
def sepia(white="#fff0c0"):
r, g, b = ImageColor.getrgb(white)
r = _make_linear_lut(0, r)
g = _make_linear_lut(0, g)
b = _make_linear_lut(0, b)
return ImagePalette("RGB", r + g + b)
def wedge(mode="RGB"):
return ImagePalette(mode, list(range(256)) * len(mode))
def load(filename):
# FIXME: supports GIMP gradients only
fp = open(filename, "rb")
lut = None
if not lut:
try:
from PIL import GimpPaletteFile
fp.seek(0)
p = GimpPaletteFile.GimpPaletteFile(fp)
lut = p.getpalette()
except (SyntaxError, ValueError):
#import traceback
#traceback.print_exc()
pass
if not lut:
try:
from PIL import GimpGradientFile
fp.seek(0)
p = GimpGradientFile.GimpGradientFile(fp)
lut = p.getpalette()
except (SyntaxError, ValueError):
#import traceback
#traceback.print_exc()
pass
if not lut:
try:
from PIL import PaletteFile
fp.seek(0)
p = PaletteFile.PaletteFile(fp)
lut = p.getpalette()
except (SyntaxError, ValueError):
import traceback
traceback.print_exc()
pass
if not lut:
raise IOError("cannot load palette")
return lut # data, rawmode