Trying to pull a font out of a bitmap

genfont.pl

#!/usr/bin/env perl
use strict;
use warnings;

use Graphics::Magick;
use Data::Dumper;
use Getopt::Long;

my $code;
my $font = "reg-bold-italic-full.png";
my $make_font;
GetOptions(
    'code+' => \$code,
    'font=s' => \$font,
    'make=s' => \$make_font,
);

my $row_offset = shift;
my $col_offset = shift;

my $gm = Graphics::Magick->new;

$gm->read($font);

my ($width, $height) = $gm->[0]->Get('columns', 'rows');


$row_offset = 0 if not defined $row_offset;
$col_offset = 0 if not defined $col_offset;

my $char_width = $width / 80;
my $char_height = $height / 25;

print "Image is $width by $height pixels\n";
print "Computed character box: [$char_width, $char_height]\n";
my $base_x = 0;
my $base_y = 0;

my $min_val = 300;
my $max_val = -1;

for (my $row = 0; $row < $height; $row += 1) {
    for (my $col = 0; $col < $width; $col += 1) {
        my $x = $col;
        my $y = $row;
        my ($pixel) = $gm->[0]->Get("pixel[$x,$y]");
        my ($g) = $pixel =~ /\d+,(\d+),\d+/;
        $g = ($g >> 8) & 0xff;
        $min_val = $g if ($g < $min_val);
        $max_val = $g if ($g > $max_val);
    }
}
print "For the image, min, max => $min_val, $max_val\n";
my $rng = ($max_val - $min_val);
my $scale = 255.0 / $rng;
printf "Dynamic range : %d, scaling %f\n", $rng, $scale;

if (defined $make_font) {
    if ($make_font eq "r") {
        all_font($gm, 1, 0, "regular-font.c");
    } elsif ($make_font eq "b") {
        all_font($gm, 1, 8 * $char_height + 1, "bold-font.c");
    }
}

print "\t{ \n" if defined $code;
for (my $row = 0; $row < $char_height; $row += 1) {
    print "\t" if defined $code;
    for (my $col = 0; $col < $char_width; $col += 1) {
        my $x = $col + $base_x + $col_offset * $char_width;
        my $y = $row + $base_y + $row_offset * $char_height;
        my ($pixel) = $gm->[0]->Get("pixel[$x,$y]");
        my ($g) = $pixel =~ /\d+,(\d+),\d+/;
        $g = ($g >> 8) & 0xff;
        if (defined $code) {
            printf("0x%x", $g);
            if ($col < 9) {
                print ", ";
            } else {
                print "},";
            }
        } else {
            printf "0x%02X ", $g;
        }
    }
    print "\n";
}

#
# 
#
#
my $num_chars = 7;

for (my $dash = 0; $dash < ($num_chars * $char_width) + 1; $dash += 1) {
    if (($dash % $char_width) == 0) {
        print "+";
    }
    print "-";
}
print "\n";
for (my $row = 0; $row < $char_height; $row += 1) {
    for (my $col = 0; $col < (7 * $char_width) + 1; $col += 1) {
        my $x = $col + $base_x + $col_offset * $char_width;
        my $y = $row + $base_y + $row_offset * $char_height;
        my ($pixel) = $gm->[0]->Get("pixel[$x,$y]");
        my ($g) = $pixel =~ /\d+,(\d+),\d+/;
        if (($col % $char_width) == 0) {
            print "|";
        }
        $g = ($g >> 8) & 0xff;
        if ($g < 127) {
            print "*";
        } else {
            print " ";
        }
    }
    print "\n";
}
for (my $dash = 0; $dash < ($num_chars * $char_width) + 1; $dash += 1) {
    if (($dash % $char_width) == 0) {
        print "+";
    }
    print "-";
}
print "\n";

sub all_font {
    my ($img, $bx, $by, $file) = @_;

    my $cw = $char_width;
    my $ch = $char_height - 3;
    print "Generating font into $file\n";

    open (my $fh, ">", $file);
    print $fh "#include <stdint.h>\n";
    print $fh "\n/* program generated font code */\n";
    print $fh "#define CHAR_WIDTH $cw\n";
    print $fh "#define CHAR_HEIGHT $ch\n";

    print $fh "const uint8_t font_glyphs[256][CHAR_HEIGHT][CHAR_WIDTH] = {\n";
    for (my $row = 0; $row < 8; $row += 1) {
        for (my $col = 0; $col < 32; $col += 1) {
            code_glyph($fh, $img, $row, $col, $ch, $cw, $bx, $by);
        }
    }
    print $fh "};\n";
    close $fh;
}
sub code_glyph {
    my ($fh, $img, $ro, $co, $ch, $cw, $bx, $by) = @_;

    my @pic;

    print $fh "\t{\n";
    for (my $row = 0; $row < $ch; $row += 1) {
        my $y = $by + $row + $ro * $char_height;
        print $fh "\t\t{";
        @pic = ();
        for (my $col = 0; $col < $cw; $col += 1) {
            my $x = $bx + $col + $co * $cw;
            my ($pixel) = $img->[0]->Get("pixel[$x,$y]");
            my ($g) = $pixel =~ /\d+,(\d+),\d+/;
            $g = ($g >> 8) & 0xff;
            my $v = (($g - $min_val) < 0) ? 0 : $g - $min_val;
            $v = ($v * $scale) > 255 ? 255 : $v * $scale;
            $v = 255 - $v; 
            if ($v < 64) {
                push @pic, " ";
            } elsif ($v < 128) { 
                push @pic, "-";
            } elsif ($v < 192) {
                push @pic, "*"; 
            } else { 
                push @pic, "@";
            }
            printf $fh ("0x%02x", $v);
            if ($col < ($char_width - 1)) {
                print $fh ", ";
            } else {
                print $fh "},";
            } 
        }       
        print $fh "/* " . join("", @pic) . " */\n";
    }           
    print $fh "\t},\n";
}