222 lines
6.2 KiB
Python
222 lines
6.2 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# image palette object
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#
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# History:
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# 1996-03-11 fl Rewritten.
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# 1997-01-03 fl Up and running.
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# 1997-08-23 fl Added load hack
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# 2001-04-16 fl Fixed randint shadow bug in random()
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#
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# Copyright (c) 1997-2001 by Secret Labs AB
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# Copyright (c) 1996-1997 by Fredrik Lundh
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#
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# See the README file for information on usage and redistribution.
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#
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import array
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from . import GimpGradientFile, GimpPaletteFile, ImageColor, PaletteFile
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class ImagePalette:
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"""
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Color palette for palette mapped images
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:param mode: The mode to use for the Palette. See:
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:ref:`concept-modes`. Defaults to "RGB"
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:param palette: An optional palette. If given, it must be a bytearray,
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an array or a list of ints between 0-255 and of length ``size``
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times the number of colors in ``mode``. The list must be aligned
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by channel (All R values must be contiguous in the list before G
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and B values.) Defaults to 0 through 255 per channel.
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:param size: An optional palette size. If given, it cannot be equal to
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or greater than 256. Defaults to 0.
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"""
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def __init__(self, mode="RGB", palette=None, size=0):
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self.mode = mode
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self.rawmode = None # if set, palette contains raw data
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self.palette = palette or bytearray(range(256)) * len(self.mode)
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self.colors = {}
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self.dirty = None
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if (size == 0 and len(self.mode) * 256 != len(self.palette)) or (
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size != 0 and size != len(self.palette)
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):
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raise ValueError("wrong palette size")
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def copy(self):
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new = ImagePalette()
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new.mode = self.mode
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new.rawmode = self.rawmode
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if self.palette is not None:
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new.palette = self.palette[:]
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new.colors = self.colors.copy()
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new.dirty = self.dirty
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return new
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def getdata(self):
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"""
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Get palette contents in format suitable for the low-level
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``im.putpalette`` primitive.
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.. warning:: This method is experimental.
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"""
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if self.rawmode:
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return self.rawmode, self.palette
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return self.mode + ";L", self.tobytes()
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def tobytes(self):
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"""Convert palette to bytes.
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.. warning:: This method is experimental.
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"""
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if self.rawmode:
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raise ValueError("palette contains raw palette data")
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if isinstance(self.palette, bytes):
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return self.palette
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arr = array.array("B", self.palette)
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if hasattr(arr, "tobytes"):
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return arr.tobytes()
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return arr.tostring()
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# Declare tostring as an alias for tobytes
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tostring = tobytes
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def getcolor(self, color):
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"""Given an rgb tuple, allocate palette entry.
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.. warning:: This method is experimental.
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"""
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if self.rawmode:
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raise ValueError("palette contains raw palette data")
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if isinstance(color, tuple):
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try:
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return self.colors[color]
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except KeyError as e:
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# allocate new color slot
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if isinstance(self.palette, bytes):
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self.palette = bytearray(self.palette)
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index = len(self.colors)
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if index >= 256:
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raise ValueError("cannot allocate more than 256 colors") from e
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self.colors[color] = index
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self.palette[index] = color[0]
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self.palette[index + 256] = color[1]
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self.palette[index + 512] = color[2]
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self.dirty = 1
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return index
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else:
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raise ValueError(f"unknown color specifier: {repr(color)}")
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def save(self, fp):
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"""Save palette to text file.
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.. warning:: This method is experimental.
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"""
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if self.rawmode:
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raise ValueError("palette contains raw palette data")
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if isinstance(fp, str):
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fp = open(fp, "w")
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fp.write("# Palette\n")
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fp.write(f"# Mode: {self.mode}\n")
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for i in range(256):
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fp.write(f"{i}")
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for j in range(i * len(self.mode), (i + 1) * len(self.mode)):
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try:
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fp.write(f" {self.palette[j]}")
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except IndexError:
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fp.write(" 0")
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fp.write("\n")
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fp.close()
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# --------------------------------------------------------------------
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# Internal
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def raw(rawmode, data):
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palette = ImagePalette()
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palette.rawmode = rawmode
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palette.palette = data
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palette.dirty = 1
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return palette
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# --------------------------------------------------------------------
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# Factories
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def make_linear_lut(black, white):
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lut = []
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if black == 0:
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for i in range(256):
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lut.append(white * i // 255)
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else:
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raise NotImplementedError # FIXME
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return lut
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def make_gamma_lut(exp):
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lut = []
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for i in range(256):
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lut.append(int(((i / 255.0) ** exp) * 255.0 + 0.5))
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return lut
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def negative(mode="RGB"):
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palette = list(range(256))
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palette.reverse()
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return ImagePalette(mode, palette * len(mode))
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def random(mode="RGB"):
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from random import randint
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palette = []
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for i in range(256 * len(mode)):
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palette.append(randint(0, 255))
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return ImagePalette(mode, palette)
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def sepia(white="#fff0c0"):
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r, g, b = ImageColor.getrgb(white)
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r = make_linear_lut(0, r)
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g = make_linear_lut(0, g)
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b = make_linear_lut(0, b)
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return ImagePalette("RGB", r + g + b)
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def wedge(mode="RGB"):
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return ImagePalette(mode, list(range(256)) * len(mode))
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def load(filename):
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# FIXME: supports GIMP gradients only
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with open(filename, "rb") as fp:
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for paletteHandler in [
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GimpPaletteFile.GimpPaletteFile,
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GimpGradientFile.GimpGradientFile,
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PaletteFile.PaletteFile,
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]:
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try:
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fp.seek(0)
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lut = paletteHandler(fp).getpalette()
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if lut:
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break
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except (SyntaxError, ValueError):
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# import traceback
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# traceback.print_exc()
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pass
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else:
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raise OSError("cannot load palette")
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return lut # data, rawmode
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