Gimp::Fu - Easy framework for Gimp-Perl scripts
use Gimp; use Gimp::Fu; podregister { # your code }; exit main; __END__ =head1 NAME function_name - Short description of the function =head1 SYNOPSIS <Image>/Filters/Menu/Location... =head1 DESCRIPTION Longer description of the function...
This module provides all the infrastructure you need to write Gimp-Perl plugins. Dov Grobgeld has written an excellent tutorial for Gimp-Perl. You can find it at http://www.gimp.org/tutorials/Basic_Perl/.
http://www.gimp.org/tutorials/Basic_Perl/
This distribution comes with many example scripts. One is examples/example-fu.pl, which is a small Gimp::Fu-script you can take as a starting point for your experiments. You should be able to run it from GIMP already by looking at "Filters/Languages/_Perl/Test/Dialog".
examples/example-fu.pl
Your main interface for using Gimp::Fu is the podregister function.
Gimp::Fu
podregister
This:
podregister { # your code };
does the same as this:
register '', '', '', '', '', '', '', '', '', sub { # your code };
It extracts all the relevant values from your script's POD documentation - see the section on "EMBEDDED POD DOCUMENTATION" for an explanation. You will also notice you don't need to provide the sub keyword, thanks to Perl's prototyping.
sub
Thanks to Filter::Simple source filtering, this podregister-ed function:
# the POD "PARAMETERS" section defines vars called "x" and "y" # the POD "SYNOPSIS" i.e. menupath starts with "<Image>" # the POD "IMAGE TYPES" says "*" - this means image and drawable params too podregister { # code... };
will also have the exact equivalent (because it's literally this) of:
podregister { my ($image, $drawable, $x, $y) = @_; # code... };
This means if you add or remove parameters in the POD, or change their order, your code will just continue to work - no more maintaining two copies of the parameter list. The above is the most common scenario, but see the "menupath" for the other possibilities for the variable names you will be supplied with.
register "function_name", "blurb", "help", "author", "copyright", "date", "menupath", "imagetypes", [ [PF_TYPE,name,desc,optional-default,optional-extra-args], [PF_TYPE,name,desc,optional-default,optional-extra-args], # etc... ], [ # like above, but for return values (optional) ], sub { code };
All these parameters except the code-ref can be replaced with '', in which case they will be substituted with appropriate values from various sections (see below) of the POD documentation in your script.
''
It is highly recommended you use the "PODREGISTER" interface, unless you wish to have more than one interface (i.e. menu entry) to your plugin, with different parameters.
Defaults to the NAME section of the POD, the part before the first -. Falls back to the script's filename.
-
The PDB name of the function, i.e. the name under which it will be registered in the GIMP database. If it doesn't start with "perl_fu_", "file_", "plug_in_" or "extension_", it will be prepended. If you don't want this, prefix your function name with a single "+". The idea here is that every Gimp::Fu plug-in will be found under the common perl_fu_-prefix.
perl_fu_
Defaults to the NAME section of the POD, the part after the first -.
A one-sentence description of this script/plug-in.
Defaults to the DESCRIPTION section of the POD.
A help text describing this script. Should give more information than blurb.
blurb
Defaults to the AUTHOR section of the POD.
The name (and also the e-mail address if possible!) of the script-author.
Defaults to the LICENSE section of the POD.
The copyright designation for this script. Important! Save your intellectual rights!
Defaults to the DATE section of the POD.
The "last modified" date of this script. There is no strict syntax here, but I recommend ISO format (yyyymmdd or yyyy-mm-dd).
Defaults to the SYNOPSIS section of the POD.
The menu entry GIMP should create. Note this is different from Script-Fu, which asks only for which menu in which to place the entry, using the second argument to (its equivalent of) register as the actual label; here, you spell out the full menu entry including label name.
register
It should start with one of the following:
If the plugin works on or produces an image.
If the "imagetypes" argument (see below) is defined and non-zero-length, Gimp::Fu will supply parameters:
PF_IMAGE called image
PF_IMAGE
PF_DRAWABLE called drawable
PF_DRAWABLE
as the first parameters to the plugin.
If the plugin is intending to create an image rather than to work on an existing one, make sure you supply undef or "" as the "imagetypes". In that case, Gimp::Fu will supply a PF_IMAGE return value if the first return value is not a PF_IMAGE.
undef
""
In any case, the plugin will be installed in the specified menu location; almost always under File/Create or Filters.
File/Create
Filters
The file-extensions are comma-separated. The prefixes are optional.
Gimp::Fu will automatically register the plugin as a load-handler using Gimp->register_load_handler.
Gimp->register_load_handler
Gimp::Fu will supply parameters:
PF_STRING called filename
PF_STRING
PF_STRING called raw_filename
as the first parameters to the plugin. It will also automatically add a return-value which is a PF_IMAGE, unless there is already such a value as first return value.
Gimp::Fu will automatically register the plugin as a save-handler using Gimp->register_save_handler. This is not (in GIMP 2.8 terms) a save-handler anymore, but an export-handler.
Gimp->register_save_handler
Outline:
podregister { my $export = Gimp::UI::export_image( my $new_image=$image, my $new_drawable=$drawable, "COLORHTML", EXPORT_CAN_HANDLE_RGB ); return if $export == EXPORT_CANCEL; # ... $new_image->delete if $export == EXPORT_EXPORT; };
This type of plugin will not have the image and drawable passed, nor will it require (or return) it. It will still have a run_mode added.
run_mode
If the script does not need to have a menu entry.
Defaults to the "IMAGE TYPES" section of the POD.
The types of images your script will accept. Examples are "RGB", "RGB*", "GRAY, RGB" etc... Most scripts will want to use "*", meaning "any type". Either undef or "" will mean "none". Not providing the relevant POD section is perfectly valid, so long as you intend to create and return an image.
Defaults to the "PARAMETERS" section of the POD, passed to eval, e.g.:
eval
=head PARAMETERS [ PF_COLOR, 'color', 'Colour', 'black' ], [ PF_FONT, 'font', 'Font', 'Arial' ],
You don't have to indent it so that POD treats it as verbatim, but it will be more readable in the Help viewer if you do.
An array reference containing parameter definitions. These are similar to the parameter definitions used for gimp_install_procedure but include an additional default value used when the caller doesn't supply one, and optional extra arguments describing some types like PF_SLIDER.
gimp_install_procedure
PF_SLIDER
Each array element has the form [type, name, description, default_value, extra_args].
[type, name, description, default_value, extra_args]
<Image>-type plugins get two additional parameters, image (PF_IMAGE) and drawable (PF_DRAWABLE) if and only if the "image types" are defined and non-zero-length. Do not specify these yourself - see the menupath entry above. Also, the run_mode argument is never given to the script but its value can be accessed in the package-global $Gimp::Fu::run_mode. The description will be used in the dialog box as a label.
menupath
$Gimp::Fu::run_mode
See the section PARAMETER TYPES for the supported types.
The default values have an effect when called from a menu in GIMP, and when the script is called from the command line. However, they have a limited effect when called from Gimp::Net; data types that do not have an "invalid" value, like text does, may not be passed as an undefined value; this is because while Perl can use undef instead of anything, GIMP cannot. For instance, it is possible to pass a PF_STRING as undef, which will then be set to the supplied default value, but not a PF_COLOR.
PF_COLOR
Defaults to the "RETURN VALUES" section of the POD, passed to eval. Not providing the relevant POD section is perfectly valid, so long as you intend to return no values.
This is just like the parameter array except that it describes the return values. Specify the type, variable name and description only. This argument is optional. If you wish your plugin to return an image, you must specify that (unless your "image types" is false, see below), e.g.:
use Gimp; use Gimp::Fu; register 'function_name', "help", "blurb", "author", "copyright", "2014-04-11", "<Image>/Filters/Render/Do Something...", "*", [ [PF_INT32, "imagesize", "Image size", 1] ], [ [PF_IMAGE, "output image", "Output image"] ], sub { Gimp::Image->new($_[0], $_[0], RGB) };
If your "image types" is false, then Gimp::Fu will ensure your first return parameter is a PF_IMAGE. If for some reason you need to return an image value that will satisfy the requirement to return the right number of values but is invalid, you can return either -1 or undef.
You must return the correct number (and types) of values from your function.
This is either an anonymous sub declaration (sub { your code here; }, or a coderef, which is called when the script is run. Arguments (including the image and drawable for <Image> plug-ins) are supplied automatically.
sub { your code here; }
You must make sure your plugin returns the correct types of value, or none:
sub { # no return parameters were specified (); };
If you want to display images, you must have your script do that. Gimp::Fu will no longer automatically do that for you, so your plugins will thereby be good GIMP "citizens", able to fit in with plugins/filters written in other languages.
All mapped to sliders or spinners with suitable min/max.
For PF_FLOAT (or PF_VALUE, a synonym), you should probably use a PF_SPINNER or PF_SLIDER with suitable values.
PF_FLOAT
PF_VALUE
PF_SPINNER
A string.
Will accept a colour argument. In dialogs, a colour preview will be created which will open a colour selection box when clicked. The default value needs to be a suitable Gimp-Perl colour; see "Gimp::canonicalize_colour" in Gimp.
[ PF_COLOR, 'colour', 'Input colour', 'white' ], [ PF_COLOR, 'colour2', 'Input colour 2', [ 255, 128, 0 ] ],
A GIMP image.
A GIMP drawable (channel or layer).
A boolean value (anything Perl would accept as true or false).
Uses a horizontal scale. To set the range and stepsize, append an array ref (see Gtk2::Adjustment for an explanation) [range_min, range_max, step_size, page_increment, page_size] as "extra argument" to the description array. Default values will be substituted for missing entries, like in:
[range_min, range_max, step_size, page_increment, page_size]
[PF_SLIDER, "alpha value", "the alpha value", 100, [0, 255, 1] ]
The same as PF_SLIDER, except that this one uses a spinbutton instead of a scale.
In addition to a default value, an extra argument describing the various options must be provided. That extra argument must be a reference to an array filled with Option-Name => Option-Value pairs. Gimp::Fu will then generate a horizontal frame with radio buttons, one for each alternative. For example:
Option-Name => Option-Value
[PF_RADIO, "direction", "direction to move to", 5, [Left => 5, Right => 7]]]
draws two buttons, when the first (the default, "Left") is activated, 5 will be returned. If the second is activated, 7 is returned.
Lets the user select a font whose name is returned as a string.
Lets the user select a brush/pattern/gradient whose name is returned as a string. The default brush/pattern/gradient-name can be preset.
Example:
[PF_CUSTOM, "direction", "Direction to fade(0-8)", 4, sub { my $btnTable = new Gtk2::Table(3,3,1); $btnTable->set_border_width(6); my $btn = new Gtk2::RadioButton; my ($u_direction, @buttons); for (my $x=0;$x<3;$x++) { for (my $y=0;$y<3;$y++) { my $dir = $x*3 + $y; $buttons[$dir] = $btn = Gtk2::RadioButton->new_from_widget($btn); $btn->set_mode(0); $btn->signal_connect("clicked", sub { $u_direction = $_[1]; }, $dir); $btn->show; $btnTable->attach_defaults($btn, $x, $x+1, $y, $y+1); my $pixmap = Gtk2::Image->new_from_pixmap( Gtk2::Gdk::Pixmap->colormap_create_from_xpm_d( undef, $btn->get_colormap, $btn->style->bg('normal'), @{$arr[$dir]} ) ); $pixmap->show; $btn->add($pixmap); } } $btnTable->show; ($btnTable, sub { $buttons[$_[0]]->clicked }, sub { $u_direction }); },],
PF_CUSTOM is for those of you requiring some non-standard-widget. You supply a reference to code returning three values as the extra argument:
PF_CUSTOM
widget
Gtk2 widget that should be used.
settor
Function that takes a single argument, the new value for the widget (the widget should be updated accordingly).
gettor
Function returning the current value of the widget.
The value set and returned must be a string. For an example of this, see examples/example-no-fu.
examples/example-no-fu
This represents a file system object. It usually is a file, but can be anything (directory, link). It might not even exist at all.
Similar to PF_STRING, but the entry widget is much larger and has Load, Save, and Edit (in external editor) buttons.
Gimp::Fu uses the Gimp::Pod module to access POD sections that are embedded in your scripts (see perlpod for an explanation of the POD documentation format) when the user hits the "Help" button in the dialog box. More importantly, various sections of the POD can be used instead of hardcoding strings in the call to register.
Most of the mentioned arguments have default values (see "THE REGISTER FUNCTION") that are used when the arguments are undefined or false, making the register call itself much shorter.
save_image(img,options_and_path)
This is the internal function used to save images, which does more than gimp_file_save.
gimp_file_save
The img is the GIMP image you want to save (which might get changed during the operation!), options_and_path denotes the filename and possibly options. If there are no options, save_image tries to deduce the filetype from the extension. The syntax for options is
img
options_and_path
save_image
[OPTIONS...:]filespec options valid for all images +F flatten the image -F do not flatten the image (default) options for GIF and PNG images +I do save as interlaced -I do not save as interlaced (default) options for GIF animations (use with -F) +L save as looping animation -L save as non-looping animation (default) -Dn default frame delay (default is 0) -Pn frame disposal method: 0=don't care, 1 = combine, 2 = replace options for PNG images -Cn use compression level n -E Do not skip ancillary chunks (default) +E Skip ancillary chunks options for JPEG images -Qn use quality "n" to save file (JPEG only) -S do not smooth (default) +S smooth before saving
Some examples:
test.jpg save the image as a simple JPEG -Q70:test.jpg the same but force a quality of 70 -I-F:test.gif save a GIF image, non-interlaced and without flattening
You can specify a file with extension .xcf, which will save in XCF format.
.xcf
Your scripts can immediately be used from the command line. E.g.
/usr/local/lib/gimp/2.0/plug-ins/example-fu -i
Use the --help flag to see the available options:
--help
Usage: .../example-fu [gimp-args..] [interface-args..] [script-args..] gimp-arguments are -h | -help | --help | -? print some help -v | --verbose be more verbose in what you do --host|--tcp HOST[:PORT] connect to HOST (optionally using PORT) (for more info, see Gimp::Net(3)) interface-arguments are -o | --output <filespec> write image to disk -i | --interact let the user edit the values first script-arguments are --width number Image width [360] --height integer Image height [100] --text string Message [example text] --longtext string Longer text [more example text] --bordersize integer (32-bit) Border size [10] --borderwidth number Border width [0.2] --font font Font --text_colour colour Text colour [[10 10 10]] --bg_colour colour Background colour [[255 128 0]] --ignore_cols boolean Ignore colours [0] --extra_image image Additional picture to ignore --extra_draw drawable (%[filename:]number or %a = active) Something to ignore as well --type data Effect type [0] --a_brush brush An unused brush --a_pattern pattern An unused pattern --a_gradients gradient An unused gradients
You may notice that the drawable above offers the option of "%[filename:]number" (or "%a") - this means you can specify which drawable by numeric ID, or if specified as %filename:number, Gimp::Fu will open that file and set the parameter to the numberth layer (starting from zero). From the command line, image may be specified either as "%number" or as a filename.
drawable
%filename:number
number
image
If interactive mode is chosen (either by specifying the command-line flag, or not giving all the arguments), and no output file is given, Gimp::Fu will add a parameter to get an output file.
If the --output option is given, the argument will be passed to save_image. This means you can specify various options on how you want the image to be saved/converted, as part of the "filename".
--output
Marc Lehmann <pcg@goof.com>
perl(1), Gimp.
To install Gimp, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Gimp
CPAN shell
perl -MCPAN -e shell install Gimp
For more information on module installation, please visit the detailed CPAN module installation guide.