Gimp::OO - Pseudo-OO for Gimp functions.

  use Gimp;             # Gimp::OO is now part of Gimp.

As you might have noticed, you can sort most gimp functions fall into three groups, depending on the name-prefix: CWgimp_, CWplug_in_, CWextension_ etc..

Whats more, there are functions groups like CWgimp_image_ or CWgimp_selection_, operating on a common object, Images and Selection in this case.

If you only had the plain syntax, your scripts would quickly aquire the vertical gimp syndrome:

 gimp_palette_set_foreground(...)
 gimp_layer_new(...)
 gimp_palette_set_background(...)
 gimp_image_add_layer(...)

etc. Of course, your fingers will suffer from severe injuries as well.

A solution to this situation is to use OO-syntax. Gimp plays some (very) dirty tricks and provides a number of classes, like CWGimp::Image and CWGimp::Palette that allow shorter identifiers to be used (all these appear with the CWGimp:: prefix as well as without, i.e. CWGimp::Palette is the same class as CWPalette).

If you call a method, CWGimp tries to find a gimp function by prepending a number of prefixes until it finds a valid function:

 $image = Gimp->image_new(...); # calls gimp_image_new(...)
 $image = Image->new(...);      # calls gimp_image_new as well
 $image = new Image(...);       # the same in green
 Palette->set_foreground(...)   # calls gimp_palette_set_foreground(..)

Return values from functions are automatically blessed (through The Magic Autobless feature ;) to their corresponding classes, i.e.

 $image = new Image(...);       # $image is now blessed to Gimp::Image
 $image->height;                # calls gimp_image_height($image)
 $image->flatten;               # likewise gimp_flatten($image)
 $image->histogram(...);        # calls gimp_histogram($image,...), since
                                # gimp_image_histogram does not exist

The class argument (CW$image in the above examples) is prepended to the argument list.

Another shortcut: many functions want a (redundant) image argument, like

 $image->shear ($layer, ...)

Since all you want is to shear the CW$layer, not the CW$image, this is confusing as well. In cases like this, Gimp allows you to write:

 $layer->shear (...)

And automatically infers the additional IMAGE-type argument.

As the (currently) last goodie, if the first argument is of type INT32, its name is run_mode and there are no other ambiguties, you can omit it, i.e. these three calls are equivalent:

 plug_in_gauss_rle (RUN_NONINTERACTIVE, $image, $layer, 8, 1, 1);
 plug_in_gauss_rle ($image, $layer, 8, 1, 1);
 plug_in_gauss_rle ($layer, 8, 1, 1);

You can call all sorts of sensible and not-so-sensible functions, so this feature can be abused:

 patterns_list Image;           # will call gimp_patterns_list
 quit Plugin;                   # will quit the Gimp, not an Plugin.

there is no image involved here whatsoever...

The following classes (with and without Gimp::) are available. The prefixes that are checked are shown as well (the null prefix "" is implicit).

Gimp (there is no Gimp::Gimp, only Gimp::)

 gimp_

Layer

 gimp_layer_
 gimp_drawable_
 gimp_floating_sel_
 gimp_image_
 gimp_
 plug_in_
 perl_fu_

Image

 gimp_image_
 gimp_drawable_
 gimp_
 plug_in_
 perl_fu_

Drawable

 gimp_drawable_
 gimp_layer_
 gimp_image_
 gimp_
 plug_in_
 perl_fu_

Selection

 gimp_selection_

Channel

 gimp_channel_
 gimp_drawable_
 gimp_selection_
 gimp_image_
 gimp_
 plug_in_
 perl_fu_

Display

 gimp_display_
 gimp_

Palette

 gimp_palette_

Plugin

 plug_in_

Gradients

 gimp_gradients_

Edit

 gimp_edit_

Progress

 gimp_progress_

Region

(none except the implicit null prefix)

Tile

 gimp_tile_

PixelRgn

 gimp_pixel_rgn_

GDrawable

 gimp_gdrawable_

Brushes

 gimp_brushes_

Patterns

 gimp_patterns_

Marc Lehmann <pcg@goof.com>

perl(1), Gimp.