#!/usr/bin/perl
use GD;
use CGI;
use constant font_directories => </var/lib/defoma/x-ttcidfont-conf.d/dirs/*>;

use constant default_font => 'Junkyard';
use constant default_size => 50;
use constant default_text => 'font->png test';
use constant default_wrap => 0;
use constant default_fore => qw(0 0 0); # black
use constant default_back => undef; # transparent
use constant default_over => 0; # don't overflow large words for text wrap

my $q = new CGI;

my $size = $q->url_param('size') || default_size;
my $text = $q->url_param('text') || default_text;
my $wrap = $q->url_param('wrap') || default_wrap;
my $over = $q->url_param('over') || default_over;

# TODO: support named colors with GD::Simple

my @fg = default_fore;
if ($q->url_param('fgcolor') =~ m/^(?:0x)([0-9a-z]{2})([0-9a-z]{2})([0-9a-z]{2})$/i) {
  @fg = map { hex } ($1, $2, $3);
}

my @bg = default_back;
if ($q->url_param('bgcolor') =~ m/^(?:0x)([0-9a-z]{2})([0-9a-z]{2})([0-9a-z]{2})$/i) {
  @bg = map { hex } ($1, $2, $3);
}

# TODO: support GD::Image->useFontConfig for finding fonts

font: for $font ($q->url_param('font'), default_font) {
  for $dir (font_directories) {
    warn "checking $dir/$font*";
    if ((@matches = <$dir/$font*>) && -f $matches[0])
    {
      $fontfile = $matches[0];
      last font;
    }
    warn "nope";
  }
}

die unless -r $fontfile;
die unless $size > 0;
die unless $text;

if ($wrap > 0) {
  use Text::Wrap qw(wrap $columns $huge);

  $columns = $wrap + 1;
  $huge = $over ? 'overflow' : 'wrap';

  $text = wrap('', '', $text);
}

my @bounds = GD::Image->stringFT(0, $fontfile, $size, 0,0,0, $text)
  or die "$! $fontfile";
my ($width, $height) = ($bounds[2] - $bounds[6],
			$bounds[3] - $bounds[7]);
my ($x, $y) = map {-$_} @bounds[6,7];

my $im = new GD::Image($width, $height) or die;

if (@bg == 3) {
  $bg = $im->colorAllocate(@bg);
} else {
  @bg = map { abs(255 - $_) } @fg; # this color isn't actually used, just set to transparent
  $im->transparent($im->colorAllocate(@bg)); # N.B. transparent color must be first color allocated; this is not documented!
}

$fg = $im->colorAllocate(@fg);
$im->stringFT($fg, $fontfile, $size, 0, $x, $y, $text);

print "Content-Type: image/png\n\n";
print $im->png or die;