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:
Whats more, there are functions groups like
gimp_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
Gimp::Palette that allow shorter identifiers to be used (all these appear
Gimp:: prefix as well as without, i.e.
Gimp::Palette is the
same class as
If you call a method,
Gimp 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 (
$image in the above examples) is prepended to the
Another shortcut: many functions want a (redundant) image argument, like
$image->shear ($layer, ...)
Since all you want is to shear the
$layer, not the
$image, this is
confusing as well. In cases like this, Gimp allows you to write:
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_layer_ gimp_drawable_ gimp_floating_sel_ gimp_image_ gimp_ plug_in_ perl_fu_
gimp_image_ gimp_drawable_ gimp_ plug_in_ perl_fu_
gimp_drawable_ gimp_layer_ gimp_image_ gimp_ plug_in_ perl_fu_
gimp_channel_ gimp_drawable_ gimp_selection_ gimp_image_ gimp_ plug_in_ perl_fu_
Marc Lehmann <email@example.com>
perl(1), the Gimp manpage.