Gimp::Util - some handy routines for Gimp-Perl users

Gimp documentation Contained in the Gimp distribution.

Index

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NAME

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 Gimp::Util - some handy routines for Gimp-Perl users

SYNOPSIS

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 use Gimp;
 use Gimp::Util;

DESCRIPTION

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Gimp-Perl is nice, but when you have to write everytime 10 lines just to get some simple functions done, it very quickly becomes tedious :-/

This module tries to define some functions that aim to automate frequently used tasks, i.e. its a sort of catch-all-bag for (possibly) useful macro functions. If you want to add a function just mail the author of the Gimp-Perl extension (see below).

In Gimp-Perl (but not in Gimp as seen by the enduser) it is possible to have layers that are NOT attached to an image. This is, IMHO a bad idea, you end up with them and the user cannot see them or delete them. So we always attach our created layers to an image here, too avoid memory leaks and debugging times.

These functions try to preserve the current settings like colors, but not all do.

These functions can also be handled in exactly the same way as PDB-Functions, i.e. the (hypothetical) function gimp_image_xyzzy can be called as $image->xyzzy, if the module is available.

The need to explicitly use Gimp::Util will go away in the future.

FUNCTIONS

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get_state (), set_state state

get_state returns a scalar representing most of gimps global state (at the moment foreground colour, background colour, active gradient, pattern and brush). The state can later be restored by a call to set_state. This is ideal for library functions such as the ones used here, at least when it includes more state in the future.

layer_create image,name,color,pos

create a colored layer, insert into image and return layer

text_draw image,layer,text,font,size,fgcolor

Create a colored text, draw over a background, add to img, ret img.

image_create_text text,font,size,fgcolor,bgcolor

Create an image, add colored text layer on a background layer, return img.

layer_add_layer_as_mask image,layer,layermask

Take a layer and add it as a mask to another layer, return mask.

gimp_text_wh $text,$fontname

returns the width and height of the "$text" of the given font (XLFD format)

gimp_image_layertype $alpha

returns the corresponding layer type for an image, alpha controls wether the layer type is with alpha or not. Example: imagetype: RGB -> RGB_IMAGE (or RGBA_IMAGE).

gimp_layer2imagetype $layertype

returns the corresponding layer type for an image, alpha controls wether the layer type is with alpha or not. Example: imagetype: RGB -> RGB_IMAGE (or RGBA_IMAGE).

gimp_image_add_new_layer $image,$index,$fill_type,$alpha

creates a new layer and adds it at position $index (default 0) to the image, after filling it with gimp_drawable_fill $fill_type (default BG_IMAGE_FILL). If $alpha is non-zero (default 1), the new layer has alpha.

gimp_image_set_visible $image,@layers, gimp_image_set_invisible $image,@layers

mark the given layers visible (invisible) and all others invisible (visible).

gimp_layer_get_position $layer

return the position the layer has in the image layer stack.

gimp_layer_set_position $layer,$new_index

moves the layer to a new position in the layer stack.

AUTHOR

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Various, version 1.000 written mainly by Tels (http://bloodgate.com/). The author of the Gimp-Perl extension (contact him to include new functions) is Marc Lehmann <pcg@goof.com>

Gimp documentation Contained in the Gimp distribution. 
package      Gimp::Util;
require      Exporter;
@ISA       = qw(Exporter);
@EXPORT    = qw(
                layer_create 
                text_draw 
                image_create_text
                layer_add_layer_as_mask
               );
#@EXPORT_OK = qw();

use Gimp;

$VERSION=1.211;

##############################################################################

sub get_state() {
   [
    Palette->get_foreground,
    Palette->get_background,
    Gradients->get_active,
    scalar Patterns->get_pattern,
    scalar Brushes->get_brush,
   ]
}

sub set_state($) {
   my $s = shift;
   Palette->set_foreground($s->[0]);
   Palette->set_background($s->[1]);
   Gradients->set_active($s->[2]);
   Patterns->set_pattern($s->[3]);
   Brushes->set_brush($s->[4]);
}

##############################################################################

# [12/23/98] v0.0.1 Tels - First version
sub layer_create {
  my ($image,$name,$color,$pos) = @_;
  my $layer;
  my $tcol; # scratch color

  # create a colored layer
  $layer = Gimp->layer_new ($image,Gimp->image_width($image),
                           Gimp->image_height($image),
                           RGB_IMAGE,$name,100,NORMAL_MODE);
  $tcol = Gimp->palette_get_background ();
  Gimp->palette_set_background ($color);
  Gimp->drawable_fill ($layer,BG_IMAGE_FILL);
  Gimp->image_add_layer($image, $layer, $pos);
  Gimp->palette_set_background ($tcol); # reset
  $layer;  
  }

##############################################################################

# [12/23/98] v0.0.1 Tels - First version
sub text_draw {
  my ($image,$layer,$text,$font,$size,$fgcolor) = @_;
  my ($bg_layer,$text_layer);
  my $tcol; # temp. color

  warn __"text string is empty" if $text eq "";
  warn __"no font specified, using default" if $font eq "";
  $font = "Helvetica" if ($font eq "");

  $tcol = Gimp->palette_get_foreground ();
  Gimp->palette_set_foreground ($fgcolor);
  # Create a layer for the text.
  $text_layer = Gimp->text($image,-1,0,0,$text,10,1,$size,
			    PIXELS,"*",$font,"*","*","*","*"); 
    
  # Do the fun stuff with the text.
  Gimp->layer_set_preserve_trans($text_layer, FALSE);

  if ($resize == 0)
    {
    # Now figure out the size of $image
    $width = Gimp->image_width($text_layer);
    $height = Gimp->image_height($text_layer);
    # and cut text layer
    }
  else
    {
    }
					  
  # add text to image
  Gimp->image_add_layer($image, $text_layer, $pos);
  # merge white and text
  Gimp->image_merge_visible_layers ($image,1);
  # cleanup the left over layer (!) 
  Gimp->layer_delete($text_layer);
  $layer;
}
    
##############################################################################

# [12/23/98] v0.0.1 Tels - First version
sub image_create_text {
  my ($text,$font,$size,$fgcolor,$bgcolor) = @_;
  my $tcol; # temp. color
  my $text_layer;
  my $bg_layer;
  my $image;

  warn (__"text string is empty") if ($text eq "");
  warn (__"no font specified, using default") if ($font eq "");
  $font = "Helvetica" if ($font eq "");
  # create an image. We'll just set whatever size here because we want
  # to resize the image when we figure out how big the text is.
  $image = Gimp->image_new(64,64,RGB); # don't waste too much  resources ;-/
    
  $tcol = Gimp->palette_get_foreground ();
  Gimp->palette_set_foreground ($fgcolor);
  # Create a layer for the text.
  $text_layer = Gimp->text($image,-1,0,0,$text,10,1,$size,
                          PIXELS,"*",$font,"*","*","*","*"); 
  Gimp->palette_set_foreground ($tcol);
    
  Gimp->layer_set_preserve_trans($text_layer, FALSE);

  # Resize the image based on size of text.
  Gimp->image_resize($image,Gimp->drawable_width($text_layer),
                    Gimp->drawable_height($text_layer),0,0);

  # create background and merge them
  $bg_layer = Gimp->layer_create ($image,"text",$bgcolor,1);
  Gimp->image_merge_visible_layers ($image,1);

  # return
  $image;
  }

##############################################################################

# [12/23/98] v0.0.1 Tels - First version
sub layer_add_layer_as_mask {
  my ($image,$layer,$layer_mask) = @_;
  my $mask;

  Gimp->selection_all ($image);  
  $layer_mask->edit_copy ();  
  Gimp->layer_add_alpha ($layer); 
  $mask = Gimp->layer_create_mask ($layer,0);
  $mask->edit_paste (0);
  Gimp->floating_sel_anchor(Gimp->image_floating_selection($image));
  Gimp->image_add_layer_mask ($image,$layer,$mask);
  $mask;
  }

##############################################################################
# all functions below are by Marc Lehmann

sub gimp_text_wh {
   (Gimp->text_get_extents_fontname($_[0],xlfd_size $_[1],$_[1]))[0,1];
}


sub gimp_image_layertype {
   my($type,$alpha) = ($_[0]->base_type,$_[1]);
   $type == RGB     ? $alpha ? RGBA_IMAGE     : RGB_IMAGE     :
   $type == GRAY    ? $alpha ? GRAYA_IMAGE    : GRAY_IMAGE    :
   $type == INDEXED ? $alpha ? INDEXEDA_IMAGE : INDEXED_IMAGE :
   die;
}

sub gimp_layer2imagetype {
   my $type = shift;
   $type == RGB_IMAGE		? RGB		:
   $type == RGBA_IMAGE		? RGB		:
   $type == GRAY_IMAGE		? GRAY		:
   $type == GRAYA_IMAGE		? GRAY		:
   $type == INDEXED_IMAGE	? INDEXED	:
   $type == INDEXEDA_IMAGE	? INDEXED	:
   die;
}

sub gimp_image_add_new_layer {
   my ($image,$index,$filltype,$alpha)=@_;
   my $layer = new Layer ($image, $image->width, $image->height, $image->layertype (defined $alpha ? $alpha : 1), join(":",(caller)[1,2]), 100, NORMAL_MODE);
   $layer->fill (defined $filltype ? $filltype : BG_IMAGE_FILL);
   $image->add_layer ($layer, $index*1);
   $layer;
}

sub gimp_image_set_visible {
   my $image = shift;
   my %layers; @layers{map $$_,@_}=(1) x @_;
   for ($image->get_layers) {
      $_->set_visible ($layers{$$_});
   }
}

sub gimp_image_set_invisible {
   my $image = shift;
   my %layers; @layers{map $$_,@_}=(1) x @_;
   for ($image->get_layers) {
      $_->set_visible (!$layers{$$_});
   }
}

sub gimp_layer_get_position {
   my $layer = shift;
   my @layers = $layer->image->get_layers;
   for (0..$#layers) {
      # the my is necessary for broken perl (return $_ => undef)
      return (my $index=$_) if ${$layers[$_]} == $$layer;
   }
   ();
}

sub gimp_layer_set_position {
   my($layer,$new_pos)=@_;
   $pos=$layer->get_position;
   $layer->add_alpha;
   while($pos>$new_pos) {
      $layer->lower_layer;
      $pos--;
   }
   while($pos<$new_pos) {
      $layer->raise_layer;
      $pos++;
   }
}