gimp/plug-ins/perl/examples/fire

#!/usr/bin/perl

use Gimp;
use Gimp::Fu;

sub fire {
   my ($image, $drawable, $threshold, $strength, $gradient, $displace) = @_;

   my ($w,$h) = ($drawable->width, $drawable->height);

   $drawable->is_layer or die "sorry, this function needs to call functions that work only for layers :(\n";

   $image->undo_push_group_start;
   $drawable->wind($threshold, 0, $strength, 0, 1);
   $drawable->wind($threshold, 1, $strength, 0, 1);
   $drawable->layer_rot270;
   $drawable->wind($threshold, 0, $strength, 0, 1);
   $drawable->wind($threshold, 1, $strength, 0, 1);
   $drawable->layer_rot90;
   $drawable->gauss_rle(($w**2+*$h**2)**0.5*0.003+1,1,1);
   $drawable->desaturate if $drawable->is_rgb;
   $drawable->ripple($w*0.05,$w*0.002,0,2,1,1,0);
   $drawable->ripple($h*0.05,$h*0.002,1,2,1,1,0);
   $drawable->displace($w*0.05,$w*0.05,1,1,$drawable,$drawable,BLACK) if $displace;
   $drawable->c_astretch;
   $drawable->map_to_gradient($gradient);
   $image->undo_push_group_end;

   ();
}

register "fire",
	 "Create a burning (depending on the gradient) halo around an object.",
	 "=pod(DESCRIPTION)",
	 "Marc Lehmann <pcg\@goof.com>",
	 "Marc Lehmann",
	 "19990802",
	 N_"<Image>/Filters/Colors/Fire",
	 "*",
	 [
          [PF_SLIDER,	"threshold",	"Intensity at which to start smearing", 10, [0,255,1]],
          [PF_SLIDER,	"strength",	"The strength (length) of the bursts", 30, [1,300,5]],
          [PF_GRADIENT,	"gradient",	"The gradient to use for the colour, e.g. 'Incandescent' or 'Burning_Paper'", 'Burning_Transparency'],
          [PF_TOGGLE,	"displace",	"Additionally displace with itself?", 0],
         ],
         [],
         ['gimp-1.1'],
         \&fire;

register "firetext",
	 "Create a burning (depending on the gradient) halo around a string (see <Image>/Filters/Color/Fire).",
	 "=pod(DESCRIPTION)",
	 "Marc Lehmann <pcg\@goof.com>",
	 "Marc Lehmann",
	 "19990802",
	 N_"<Toolbox>/Xtns/Render/Logos/Firetext",
	 "*",
	 [
          [PF_TEXT,	"text",		"The text to render (can be multi-line)", "burn,\nBurn,\nBURN!"],
          [PF_FONT,	"font",		"The font to use"],
          [PF_TOGGLE,	"inverse",	"Invert source mask?", 1],
          [PF_SLIDER,	"strength",	"The strength (length) of the bursts", 10, [1,300,5]],
          [PF_GRADIENT,	"gradient",	"The gradient to use for the colour, e.g. 'Incandescent' or 'Burning_Paper'", 'Burning_Transparency'],
          [PF_TOGGLE,	"displace",	"Additionally displace with itself?", 0],
         ],
         [PF_IMAGE],
         ['gimp-1.1'],
	 sub {
   my ($text, $font, $inverse, $strength, $gradient, $displace) = @_;

   $text =~ s/[\r\n]+$//;
   
   if ($inverse) {
      Palette->set_foreground('black');
      Palette->set_background('white');
   } else {
      Palette->set_foreground('white');
      Palette->set_background('black');
   }

   my ($w,$h) = Gimp->text_get_extents_fontname($text, xlfd_size $font, $font);
   my $image = new Image $w+40, $h+40, RGB;

   $image->undo_disable;
   
   my $layer = new Layer $image, $w+40, $h+40, RGBA_IMAGE, "text layer", 100, NORMAL_MODE;
   $layer->fill(BG_IMAGE_FILL);
   $layer->add_layer(0);
   $layer->text_fontname(20,20, $text,0, 1, xlfd_size $font, $font)->anchor;

   fire($image,$layer,5,$strength,$gradient,$displace);

   Palette->set_foreground('black');
   $image->text_fontname(-1,20-10*$displace,20-10*$displace, $text,0, 1, xlfd_size $font, $font);

   $image->undo_enable;
   $image->clean_all;

   ($image);
};

exit main;

=head1 DESCRIPTION

This plug-in creates a kind of "burning" effect around a drawable. Both
black-on-white and white-on-black source images make sense and create
different effects (do not use displace with black-on-white drawables,
though ;).

Although the original colour of the image does not matter, supplying a
greyscale drawable (though working) does not look very cool.