gimp/tools/pdbgen/pdb/gradients.pdb

# The GIMP -- an image manipulation program
# Copyright (C) 1995 Spencer Kimball and Peter Mattis

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

# "Perlized" from C source by Manish Singh <yosh@gimp.org>

sub pdb_misc {
    $author = $copyright = 'Federico Mena Quintero';
    $date = '1997';
}

sub gradients_get_list {
    $blurb = 'Retrieve the list of loaded gradients.';

    $help = <<'HELP';
This procedure returns a list of the gradients that are currently loaded in the 
gradient editor. You can later use the gimp-gradients-set-active function to
set the active gradient.
HELP

    &pdb_misc;

    @outargs = (
	{ name => 'gradient_names', type => 'stringarray',
	  desc => 'The list of gradient names', alias => 'gradients',
	  array => { name => 'num_gradients',
		     desc => 'The number of loaded gradients',
		     no_declare => 1 } }
    );

    %invoke = (
	headers => [ qw("gradient.h") ],
	vars => ['gradient_t *grad', 'GSList *list', 'int i = 0'],
	success => 'NONE',
	code => <<'CODE'
{
  gradients = g_new (gchar *, num_gradients);

  success = (list = gradients_list) != NULL;

  while (list)
    {
      grad           = list->data;
      gradients[i++] = g_strdup (grad->name);
      list           = list->next;
    }
}
CODE
    );
}

sub gradients_get_active {
    $blurb = 'Retrieve the name of the active gradient.';

    $help = <<'HELP';
This procedure returns the name of the active gradient in the gradient editor.
HELP

    &pdb_misc;

    @outargs = (
	{ name  => 'name', type  => 'string',
	  desc  => 'The name of the active gradient',
	  alias => 'g_strdup (curr_gradient->name)', no_declare => 1 }
    );

    %invoke = (
	headers => [ qw("gradient.h") ],
	code => 'success = curr_gradient != NULL;'
    );
}

sub gradients_set_active {
    $blurb = 'Sets the specified gradient as the active gradient.';

    $help = <<'HELP';
This procedure lets you set the specified gradient as the active or "current"
one. The name is simply a string which corresponds to one of the loaded
gradients in the gradient editor. If no matching gradient is found, this
procedure will return an error. Otherwise, the specified gradient will become
active and will be used for subsequent custom gradient operations.
HELP

    &pdb_misc;

    @inargs = (
	{ name => 'name', type => 'string',
	  desc => 'The name of the gradient to set' }
    );

    %invoke = (
	headers => [ qw("gradient.h") ],
	code => 'success = grad_set_grad_to_name (name);'
    );
}

sub sample_num_arg {
    { name => 'num_samples', type => $_[0] . 'int32',
      desc => 'The number of samples to take', alias => 'i' }
}

sub sample_outargs {
    @outargs = (
        { name => 'color_samples', type => 'floatarray',
	  desc => 'Color samples: { R1, G1, B1, A1, ..., Rn, Gn, Bn, An }',
	  array => { name => 'array_length', no_lib => 1,
		     desc => 'Length of the color_samples array (4 *
			      num_samples)' } }
    );
}

sub gradients_sample_uniform {
    $blurb = 'Sample the active gradient in uniform parts.';

    $help = <<'HELP';
This procedure samples the active gradient from the gradient editor in the
specified number of uniform parts. It returns a list of floating-point values
which correspond to the RGBA values for each sample. The minimum number of
samples to take is 2, in which case the returned colors will correspond to the
{ 0.0, 1.0 } positions in the gradient. For example, if the number of samples
is 3, the procedure will return the colors at positions { 0.0, 0.5, 1.0 }.
HELP

    &pdb_misc;

    @inargs = ( &sample_num_arg('2 <= ') );
    &sample_outargs;

    %invoke = (
	headers => [ qw("gradient.h") ],
	vars => ['gdouble pos, delta', 'gdouble r, g, b, a', 'gdouble *pv'],
	code => <<'CODE'
{
  pos = 0.0;
  delta = 1.0 / (i - 1);

  array_length = i * 4;

  pv = color_samples = g_new (gdouble, array_length);

  while (i--)
    {
      grad_get_color_at(pos, &r, &g, &b, &a);

      *pv++ = r;
      *pv++ = g;
      *pv++ = b;
      *pv++ = a;

      pos += delta;
    }
}
CODE
    );
}

sub gradients_sample_custom {
    $blurb = 'Sample the active gradient in custom positions.';

    $help = <<'HELP';
This procedure samples the active gradient from the gradient editor in the
specified number of points. The procedure will sample the gradient in the
specified positions from the list. The left endpoint of the gradient
corresponds to position 0.0, and the right endpoint corresponds to 1.0. The
procedure returns a list of floating-point values which correspond to the RGBA
values for each sample.
HELP

    &pdb_misc;

    @inargs = (
	{
	    name  => 'positions',
	    type  => 'floatarray',
	    desc  => 'The list of positions to sample along the gradient',
	    alias => 'pos',
	    array => &sample_num_arg("")
	}
    );

    &sample_outargs;

    %invoke = (
	headers => [ qw("gradient.h") ],
	vars => ['gdouble r, g, b, a', 'gdouble *pv'],
	code => <<'CODE'
{
  array_length = i * 4;

  pv = color_samples = g_new (gdouble, array_length);

  while (i--)
    {
      grad_get_color_at(*pos, &r, &g, &b, &a);

      *pv++ = r;
      *pv++ = g;
      *pv++ = b;
      *pv++ = a;

      pos++;
    }
}
CODE
    );
}

@procs = qw(gradients_get_list gradients_get_active gradients_set_active
	    gradients_sample_uniform gradients_sample_custom);
%exports = (app => [@procs], lib => [@procs]);

$desc = 'Gradients';

1;