#
# The Python Imaging Library.
# $Id$
#
# PIL raster font management
#
# History:
# 96-08-07 fl	created (experimental)
# 97-08-25 fl	minor adjustments to handle fonts from pilfont 0.3
# 99-02-06 fl	rewrote most font management stuff in C
# 99-03-17 fl	take pth files into account in load_path (from Richard Jones)
#
# Todo:
# Adapt to PILFONT2 format (16-bit fonts, compressed, single file)
#
# Copyright (c) Secret Labs AB 1997-99
# Copyright (c) Fredrik Lundh 1996-97
#
# See the README file for information on usage and redistribution.
#

import Image
import glob, os, string, sys

# --------------------------------------------------------------------
# Font metrics format:
#	"PILfont" LF
#	fontdescriptor LF
#	(optional) key=value... LF
#	"DATA" LF
#	binary data: 256*10*2 bytes (dx, dy, dstbox, srcbox)
#
# To place a character, cut out srcbox and paste at dstbox,
# relative to the character position.  Then move the character
# position according to dx, dy.
# --------------------------------------------------------------------

class ImageFont:

    def _load_pilfont(self, filename):

	fp = open(filename, "rb")

	# read PILfont header
	if fp.readline() != "PILfont\n":
	    raise SyntaxError, "Not a PILfont file"
	d = string.split(fp.readline(), ";")
	self.info = [] # FIXME: should be a dictionary
	s = fp.readline()
	while s and s != "DATA\n":
	    self.info.append(s)

	# read PILfont metrics
	data = fp.read(256*20)

	# read PILfont bitmap
	image = None
	for ext in (".png", ".gif", ".pbm"):
	    try:
		image = Image.open(os.path.splitext(filename)[0] + ext)
	    except:
		pass
	    if image:
		break
	if image is None:
	    raise IOError, "cannot find glyph data file"

	image.load()
	self.font = Image.core.font(image.im, data)

	# delegate critical operations to internal type
	self.getsize = self.font.getsize
	self.getmask = self.font.getmask

#
# --------------------------------------------------------------------

def load(filename):
    "Load a font file."
    f = ImageFont()
    f._load_pilfont(filename)
    return f

def load_path(filename):
    "Load a font file, searching along the Python path."
    for dir in sys.path:
	try:
	    return load(os.path.join(dir, filename))
	except IOError:
	    pass
	for extra in glob.glob(os.path.join(dir, "*.pth")):
	    try:
		dir = os.path.join(dir, string.strip(open(extra).read()))
		return load(os.path.join(dir, filename))
	    except IOError:
		pass
    raise IOError, "cannot find font file"