XpmImagePlugin.py

#
# The Python Imaging Library.
# $Id$
#
# XPM File handling
#
# History:
# 1996-12-29 fl   Created
# 2001-02-17 fl   Use 're' instead of 'regex' (Python 2.1) (0.7)
#
# Copyright (c) Secret Labs AB 1997-2001.
# Copyright (c) Fredrik Lundh 1996-2001.
#
# See the README file for information on usage and redistribution.
#


__version__ = "0.2"


import re, string
import Image, ImageFile, ImagePalette

# XPM header
xpm_head = re.compile("\"([0-9]*) ([0-9]*) ([0-9]*) ([0-9]*)")


def _accept(prefix):
    return prefix[:9] == "/* XPM */"

##
# Image plugin for X11 pixel maps.

class XpmImageFile(ImageFile.ImageFile):

    format = "XPM"
    format_description = "X11 Pixel Map"

    def _open(self):

        if not _accept(self.fp.read(9)):
            raise SyntaxError, "not an XPM file"

        # skip forward to next string
        while 1:
            s = self.fp.readline()
            if not s:
                raise SyntaxError, "broken XPM file"
            m = xpm_head.match(s)
            if m:
                break

        self.size = int(m.group(1)), int(m.group(2))

        pal = int(m.group(3))
        bpp = int(m.group(4))

        if pal > 256 or bpp != 1:
            raise ValueError, "cannot read this XPM file"

        #
        # load palette description

        palette = ["\0\0\0"] * 256

        for i in range(pal):

            s = self.fp.readline()
            if s[-2:] == '\r\n':
                s = s[:-2]
            elif s[-1:] in '\r\n':
                s = s[:-1]

            c = ord(s[1])
            s = string.split(s[2:-2])

            for i in range(0, len(s), 2):

                if s[i] == "c":

                    # process colour key
                    rgb = s[i+1]
                    if rgb == "None":
                        self.info["transparency"] = c
                    elif rgb[0] == "#":
                        # FIXME: handle colour names (see ImagePalette.py)
                        rgb = string.atoi(rgb[1:], 16)
                        palette[c] = chr((rgb >> 16) & 255) +\
                                     chr((rgb >> 8) & 255) +\
                                     chr(rgb & 255)
                    else:
                        # unknown colour
                        raise ValueError, "cannot read this XPM file"
                    break

            else:

                # missing colour key
                raise ValueError, "cannot read this XPM file"

        self.mode = "P"
        self.palette = ImagePalette.raw("RGB", string.join(palette, ""))

        self.tile = [("raw", (0, 0)+self.size, self.fp.tell(), ("P", 0, 1))]

    def load_read(self, bytes):

        #
        # load all image data in one chunk

        xsize, ysize = self.size

        s = [None] * ysize

        for i in range(ysize):
            s[i] = string.ljust(self.fp.readline()[1:xsize+1], xsize)

        self.fp = None

        return string.join(s, "")

#
# Registry

Image.register_open("XPM", XpmImageFile, _accept)

Image.register_extension("XPM", ".xpm")

Image.register_mime("XPM", "image/xpm")