fontconverter

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

use Data::Dumper;

my $fontname = "Terminal11x16";
## https://github.com/moononournation/Arduino_GFX/blob/master/src/Arduino_GFX.cpp: baseline = yadvance * 2 / 3
## so we have to set yadvance = (baseline * 3 / 2).
## baseofs is baseline offset from bottom, i.e. baseline = height - baseofs
## so lets try... (for Terminal11x16, baseline is 14 pixel from top, height is 16)
my $baseofs = 4;

my @data;
# read font bitmap
while(<>) {
   my @dt = map { $_=~/(0x..)/ ? (hex($1)) : () } split(/,/,$_);
   push @data, @dt;
}

my $width = shift @data;
my $height = shift @data;
my $first = shift @data;
my $count = shift @data;
my $nbrows = int(($height+7)/8);
my $charofs = $width * $nbrows + 1;

## process all glyphs
my @bitmap;
my @glyph;
my $bitofs = 0;

#$count=2;

sub optimize_glyph {
  my $w = shift;
  my $h = shift;
  my $pix = shift;
  my $xofs = 0;
  my $yofs = 0;

  # shrink 2D pixel array if possible
  while(@$pix) {
    if ( @{$pix->[0]} == grep { $_ == 0 } @{$pix->[0]} ) { shift(@$pix); $yofs++; $h--; }
    else { last; }
  }
  while(@$pix) {
    if ( @{$pix->[-1]} == grep { $_ == 0 } @{$pix->[-1]} ) { pop(@$pix); $h--; }
    else { last; }
  }

  # transform 2D pixel array into compact byte sequence
  my @all;
  for(@$pix) { push @all, @$_; }
  #print("pix size: ".(@all)."\n");
  my @res;
  while(@all) {
    my @b = splice(@all,0,8);
    while(@b<8) { push @b,0; }
    my $res = 0;
    while(@b) { $res = ($res*2) + (shift(@b)?1:0); }
    push @res,$res;
  }
  return ($w, $h, \@res, $xofs, $yofs);
}

for my $c ($first .. $first+$count-1) {
  # Convert char $c
  my @gly = splice(@data,0,$charofs);
  my $glywidth = shift @gly;
  my @pixmap;
  # print("Converting $c ($width x $height => nbrows=$nbrows)");
  for my $x (0..$glywidth-1) {
    for my $y (0..$height-1) {
      my $g = $gly[$x * $nbrows + int($y/8)];
      $pixmap[$y]->[$x] = (($g >> ($y%8))&1) ? 1 : 0;
      #print("$x, $y : $pixmap[$y]->[$x]\n");
    }
  } 
  # pixmap is now my glyph
  my ($w, $h, $d, $xofs, $yofs) = optimize_glyph($glywidth, $height, \@pixmap);

  my $glyph = {
    "offset" => $bitofs,
    "width" => $w,
    "height" => $h,
    "xadv" => $w+1,
    "xofs" => $xofs,
    "yofs" => -$height + $yofs + $baseofs,
    "c" => $c,
  };
  push @bitmap, @$d;
  $bitofs += @$d;
  push @glyph, $glyph;

  #print(Dumper($glyph,$d));
}

#print(Dumper(\@glyph));

printf("const uint8_t %sBitmap[] = {\n", $fontname);
while(my @bm = splice(@bitmap,0,12)) { print( "  ".join(", ", map { sprintf("0x%02X",$_) } @bm ).",\n" ); }
print("};\n\n");

printf("const GFXglyph %sGlyphs[] = {\n", $fontname);
for my $gl (@glyph) {
  printf("  { %5d, %3d, %3d, %3d, %4d, %4d },  // 0x%02x '%c'\n ", $gl->{"offset"}, $gl->{"width"}, $gl->{"height"},
	$gl->{"xadv"}, $gl->{"xofs"}, $gl->{"yofs"}, $gl->{"c"}, $gl->{"c"});
}
print("};\n");

printf("const GFXfont %sFont = {\n", $fontname);
printf("  (uint8_t  *)%sBitmap,\n", $fontname);
printf("  (GFXglyph *)%sGlyphs,\n", $fontname);
printf("  0x%02X, 0x%02X, %d };\n", $first, $first+$count-1, ($height-$baseofs)*3/2);