#!/usr/bin/perl

#  unihex2png - program to turn a GNU Unifont hex glyph page of 256 code
#               points into a PNG file
#
#  Synopsis: unihex2png [-i in_file.hex] [-o out_file.png]
#
#
#  Author: Paul Hardy, unifoundry <at> unifoundry.com, December 2007
#
#  Perl conversion: Andrew Miller, August 2013
#
#
#   Copyright (C) 2007-2008 Paul Hardy
#
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.

use Getopt::Long;
use GD;

$result = GetOptions (
	"help|?",
	"input|i=s" => \$input,
	"output|o=s" => \$output,
	"page|p=s" => \$page,
	"rows|r=i" => \$charheight
);

if ($opt_help) {
	print << "END" or die ("Cannot print to stdout.\n");

Turn a GNU Unifont hex glyph page of 256 code points into a PNG file

Syntax:

   unihex2png -i <Input_File> [-o <Output_File>] [-p <Page>] [-r <Rows>]

   -i, --input      the input hex file (read from STDIN if not specified)
   -o, --output     the output PNG file
   -p, --page       the Unicode page to convert - valid values are
                    0 to 10FF (default is 0)
   -r, --rows       the height of the output glyphs in pixel rows -
                    valid values are 16, 24 and 32 (default is 16)
   -?, --help       display this help and exit


Example:

   unihex2png -i unifont.hex -o u83.png -p 83

END
	exit ()
}

#if (not $input) {
#	die ("No input file specified\n")
#}

if (not $output) {
	die ("No output file specified\n")
}

if (not $page) {
	$page = 0
}

$pagenum = hex ($page);

if ($pagenum > 0x10FF) {
	die ("Invalid page\n");
}

$charxoffset = 4;
$gridxoffset = 48;
$gridyoffset = 32;

if (not $charheight) {
	$charheight = 16;
}

if ($charheight == 16) {
	$charyoffset = 7;
	$boxsize = 32;
	$xmax = 2;
	$ymax = 1;
	$charmaxwidth = 6;
} elsif ($charheight == 24) {
	$charyoffset = 4;
	$boxsize = 32;
	$xmax = 2;
	$ymax = 2;
	$charmaxwidth = 6;
} elsif ($charheight == 32) {
	$charyoffset = 4;
	$boxsize = 40;
	$xmax = 3;
	$ymax = 3;
	$charmaxwidth = 8;
} else {
	die ("Invalid height\n");
}

# Create box and set as tile pattern

$box = new GD::Image ($boxsize, $boxsize);

$black = $box->colorAllocate (0, 0, 0);
$white = $box->colorAllocate (255, 255, 255);

$box->filledRectangle (1, 1, $boxsize - 1, $boxsize - 1, $white);

# Draw dots at 8 pixel boundaries
 for ($count = 0; $count <= $xmax; $count++) {
	$box->setPixel (($count * 8) + $charxoffset + 1, 0, $white);
	$box->setPixel (($count * 8) + $charxoffset + 8, 0, $white);
}

for ($count = 0; $count <= $ymax; $count++) {
	$box->setPixel (0, ($count * 8) + $charyoffset + 1, $white);
	$box->setPixel (0, ($count * 8) + $charyoffset + 8, $white);
}

# Draw grid

$im = new GD::Image ($boxsize * 16 + $gridxoffset, $boxsize * 16 + $gridyoffset);

$black = $im->colorAllocate (0, 0, 0);
$white = $im->colorAllocate (255, 255, 255);

$im->fill (0, 0, $white);

for ($xcount = 0; $xcount <= 16; $xcount++) {
	for ($ycount = 0; $ycount <= 16; $ycount++) {
		$im->copy ($box, $xcount * $boxsize + $gridxoffset - 1, $ycount * $boxsize + $gridyoffset - 1, 0, 0, $boxsize, $boxsize);
	}
}

# Print plane
$im->string (gdLargeFont, 8, 9, sprintf ('U+%02X', $pagenum >> 8), $black);

# Print row headers
for ($count = 0; $count <= 15; $count++) {
	$im->string (gdLargeFont, 32, ($count * $boxsize) + (($boxsize - 16) / 2) + $gridyoffset, sprintf ('%X', $count), $black);
}

# Print column headers
for ($count = 0; $count <= 15; $count++) {
	$im->string (gdLargeFont, ($count * $boxsize) + (($boxsize - 24) / 2) + $gridxoffset, 9, sprintf ('%03X', (($pagenum & 0xFF) << 4) + $count), $black);
}

if ($input) {
	open (HEXFILE, "$input") or die ('Cannot open hex file for input.\n');
} else {
   *HEXFILE = *STDIN;
}

while (<HEXFILE>) {
	chomp;
	@data = split (':', $_);
	$codepoint = hex ($data[0]);

	# Calculate if codepoint is within page
	if ($codepoint >> 8 == $pagenum) {
		$char = $data[1];

		# Calculate character width, column and row
		$charwidth = length ($char) / $charheight;
		
		if ($charwidth <= $charmaxwidth) {
			$col = ($codepoint >> 4) & 0xF;
			$row = $codepoint & 0xF;

			for ($j = 0; $j < $charheight; $j++) {
				# Get character row
				$r = hex (substr ($char, $j * $charwidth, $charwidth));

				# Draw character
				for ($i = 0; $i < $charwidth * 4; $i++) {
					if ($r & 1 << $i) {
						$im->setPixel (($col * $boxsize) + ($charwidth * 4 - $i) + $charxoffset + $gridxoffset - 1, ($row * $boxsize) + $j + $charyoffset + $gridyoffset, $black);
					}
				}
			}
		}
	}
}
# Only close input file handler if it isn't STDIN.
if ($input) {
	close HEXFILE or die ("Cannot properly close input file.\n");
}

# Save image
open (PICTURE, ">$output") or die ("Cannot save image.\n");
binmode PICTURE;
print PICTURE $im->png or die ("Cannot write to picture file.\n");
close PICTURE or die ("Cannot properly close output file.\n");