# mk_font.py
#
# Translate Font BDF file into a C header.
# 
# Written & released by Keir Fraser <keir.xen@gmail.com>
# 
# This is free and unencumbered software released into the public domain.
# See the file COPYING for more details, or visit <http://unlicense.org>.

import re, sys

# Range of char codes we are interested in
first = 0x20
last = 0x7e

def main(argv):
    in_f = open(argv[1], "r")
    out_f = open(argv[2] + ".c", "w")
    out_f.write("/* Autogenerated by " + argv[0] + " */\n")
    prev = first - 1
    # Find font size
    for line in in_f:
        match = re.match("^FONTBOUNDINGBOX ([0-9]+) ([0-9]+) ([0-9]+) ([-0-9]+)", line)
        if match:
            break
    width = int(match.group(1))
    height = int(match.group(2))
    y_base = int(match.group(4))
    gap = 16 - height
    tgap = gap // 2
    bgap = gap - tgap
    out_f.write("const uint8_t %s[] aligned(4) = {\n" % argv[2])
    for line in in_f:
        # Look for a new character encoding
        match = re.match("^ENCODING ([0-9]+)", line)
        #match = re.match("[ \t]*([A-Za-z0-9-]+)[ \t]*=[ \t]*"
        #                 "([A-Za-z0-9-]+|\".*\")", line)
        if not match:
            continue
        # Extract the decimal character code point
        code = int(match.group(1))
        # Skip uninteresting code points
        if code < first or code > last:
            continue
        # This script assumes the char set is in code-point order
        assert code == prev + 1
        prev = code
        # Scan for start of bitmap data
        x_shift = 0
        top_space = 0
        bottom_space = 0
        for line in in_f:
            bbx = re.match("^BBX ([0-9]+) ([0-9]+) ([0-9]+) ([-0-9]+)", line)
            if bbx:
                x_shift = int(bbx.group(3))
                y_height = int(bbx.group(2))
                y_shift = int(bbx.group(4))
                bottom_space = y_shift - y_base
                top_space = height - (bottom_space + y_height)
            if re.match("BITMAP", line):
                break
        # Process bitmap data up to end-char
        char = []
        top_space += tgap
        for i in range(top_space):
            char.append(0)
        for line in in_f:
            if re.match("ENDCHAR", line):
                break
            match = re.match("([0-9A-F]+)", line)
            char.append(int(match.group(1), 16) >> x_shift)
        bottom_space += bgap
        for i in range(bottom_space):
            char.append(0)
        # Convert row-wise data to column-wise
        while char:
            out_f.write("    ")
            mask = 0x80
            for i in range(width):
                col = 0
                for j in range(8):
                    col //= 2
                    if char[j] & mask:
                        col = col + 0x80
                out_f.write("0x%02x, " % (col))
                mask //= 2
            char = char[8:]
            if not char:
                out_f.write(" /* '%c' %02u */" % (code, code-first))
            out_f.write("\n")
    out_f.write("};\n");
    # Assert we found all interesting code points
    assert prev == last

if __name__ == "__main__":
    main(sys.argv)