# Source code for PIL.XbmImagePlugin

    #
    # The Python Imaging Library.
    # $Id$
    #
    # XBM File handling
    #
    # History:
    # 1995-09-08 fl   Created
    # 1996-11-01 fl   Added save support
    # 1997-07-07 fl   Made header parser more tolerant
    # 1997-07-22 fl   Fixed yet another parser bug
    # 2001-02-17 fl   Use 're' instead of 'regex' (Python 2.1) (0.4)
    # 2001-05-13 fl   Added hotspot handling (based on code from Bernhard Herzog)
    # 2004-02-24 fl   Allow some whitespace before first #define
    #
    # Copyright (c) 1997-2004 by Secret Labs AB
    # Copyright (c) 1996-1997 by Fredrik Lundh
    #
    # See the README file for information on usage and redistribution.
    #

    import re

    from . import Image, ImageFile

    # XBM header
    xbm_head = re.compile(
        br"\s*#define[ \t]+.*_width[ \t]+(?P<width>[0-9]+)[\r\n]+"
        b"#define[ \t]+.*_height[ \t]+(?P<height>[0-9]+)[\r\n]+"
        b"(?P<hotspot>"
        b"#define[ \t]+[^_]*_x_hot[ \t]+(?P<xhot>[0-9]+)[\r\n]+"
        b"#define[ \t]+[^_]*_y_hot[ \t]+(?P<yhot>[0-9]+)[\r\n]+"
        b")?"
        b"[\\000-\\377]*_bits\\[\\]"
    )

    def _accept(prefix):
        return prefix.lstrip()[:7] == b"#define"

    ##
    # Image plugin for X11 bitmaps.

    class XbmImageFile(ImageFile.ImageFile):

        format = "XBM"
        format_description = "X11 Bitmap"

        def _open(self):

            m = xbm_head.match(self.fp.read(512))

            if m:

                xsize = int(m.group("width"))
                ysize = int(m.group("height"))

                if m.group("hotspot"):
                    self.info["hotspot"] = (int(m.group("xhot")), int(m.group("yhot")))

                self.mode = "1"
                self._size = xsize, ysize

                self.tile = [("xbm", (0, 0) + self.size, m.end(), None)]

    def _save(im, fp, filename):

        if im.mode != "1":
            raise OSError(f"cannot write mode {im.mode} as XBM")

        fp.write(f"#define im_width {im.size[0]}\n".encode("ascii"))
        fp.write(f"#define im_height {im.size[1]}\n".encode("ascii"))

        hotspot = im.encoderinfo.get("hotspot")
        if hotspot:
            fp.write(f"#define im_x_hot {hotspot[0]}\n".encode("ascii"))
            fp.write(f"#define im_y_hot {hotspot[1]}\n".encode("ascii"))

        fp.write(b"static char im_bits[] = {\n")

        ImageFile._save(im, fp, [("xbm", (0, 0) + im.size, 0, None)])

        fp.write(b"};\n")

    Image.register_open(XbmImageFile.format, XbmImageFile, _accept)
    Image.register_save(XbmImageFile.format, _save)

    Image.register_extension(XbmImageFile.format, ".xbm")

    Image.register_mime(XbmImageFile.format, "image/xbm")