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projecten1/lib/python3.6/site-packages/PIL/ImagePalette.py

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+#
+# 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 . import ImageColor, GimpPaletteFile, GimpGradientFile, PaletteFile
+
+
+class ImagePalette(object):
+    """
+    Color palette for palette mapped images
+
+    :param mode: The mode to use for the Palette. See:
+        :ref:`concept-modes`. Defaults to "RGB"
+    :param palette: An optional palette. If given, it must be a bytearray,
+        an array or a list of ints between 0-255 and of length ``size``
+        times the number of colors in ``mode``. The list must be aligned
+        by channel (All R values must be contiguous in the list before G
+        and B values.) Defaults to 0 through 255 per channel.
+    :param size: An optional palette size. If given, it cannot be equal to
+        or greater than 256. Defaults to 0.
+    """
+
+    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 bytearray(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 copy(self):
+        new = ImagePalette()
+
+        new.mode = self.mode
+        new.rawmode = self.rawmode
+        if self.palette is not None:
+            new.palette = self.palette[:]
+        new.colors = self.colors.copy()
+        new.dirty = self.dirty
+
+        return new
+
+    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'):
+            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 = bytearray(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.mode), (i+1)*len(self.mode)):
+                try:
+                    fp.write(" %d" % self.palette[j])
+                except IndexError:
+                    fp.write(" 0")
+            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):
+    lut = []
+    for i in range(256):
+        lut.append(int(((i / 255.0) ** exp) * 255.0 + 0.5))
+    return lut
+
+
+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
+
+    with open(filename, "rb") as fp:
+
+        for paletteHandler in [
+            GimpPaletteFile.GimpPaletteFile,
+            GimpGradientFile.GimpGradientFile,
+            PaletteFile.PaletteFile
+        ]:
+            try:
+                fp.seek(0)
+                lut = paletteHandler(fp).getpalette()
+                if lut:
+                    break
+            except (SyntaxError, ValueError):
+                # import traceback
+                # traceback.print_exc()
+                pass
+        else:
+            raise IOError("cannot load palette")
+
+    return lut  # data, rawmode