use Glib qw/TRUE FALSE/;
use Gtk2 '-init';

my ($hscale, $vscale);

sub cb_pos_menu_select
{
	my ($widget, $pos) = @_;
	$hscale->set_value_pos($pos);
	$vscale->set_value_pos($pos);
}

sub cb_update_menu_select
{
	my ($widget, $policy) = @_;
	$hscale->set_update_policy($policy);
	$vscale->set_update_policy($policy);
}

sub cb_digits_scale
{
	my ($adjustment) = @_;
	# Set the number of decimal places to which adj->value is rounded
	$hscale->set_digits($adjustment->value);
	$vscale->set_digits($adjustment->value);
}

# We do not have a Glib::CLAMP function, so we provide it here.
sub clamp ($val, $low, $high)
{
	return (($val > $high) ? $high : (($val < $low) ? $low : $val));
}

sub cb_page_size
{
	my ($get, $set) = @_;
	
	# Set the page size and page increment size of the sample
	# adjustment to the value specified by the "Page Size" scale
	$set->page_size($get->value);
	$set->page_increment($get->value);

	# This sets the adjustment and make it emit the "changed" signal to
	# reconfigure all the widgets that are attached to this signal.
	$set->set_value(clamp ($set->value,
	                       $set->upper - $set->page_size,
			       $set->lower));
	
	$set->signal_emit("changed");
}

sub cb_draw_value
{
	my $button = shift;
	$hscale->set_draw_value($button->get_active());
	$vscale->set_draw_value($button->get_active());
}

# Convenience functions
sub make_menu_item
{
	my ($name, $func, $data) = @_;
	$item = Gtk2::MenuItem->new_with_label($name);
	$item->signal_connect(activate => $func, $data);
	$item->show;

	return $item;
}

sub scale_set_default_values
{
	my $scale = shift;
	$scale->set_update_policy('continuous');
	$scale->set_digits(1);
	$scale->set_value_pos('top');
	$scale->set_draw_value(TRUE);
}

# makes the sample window
sub create_range_controls
{
	# Standard window-creating stuff
	$window = Gtk2::Window->new('toplevel');
	$window->signal_connect(destroy => sub { Gtk2->main_quit; });
	$window->set_title("range controls");

	$box1 = Gtk2::VBox->new(FALSE, 0);
	$window->add($box1);
	$box1->show;

	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);
	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	# value, lower, upper, step_increment, page_increment, page_size
	# Note that the page_size value only makes a difference for
	# scrollbar widgets, and the highest value you'll get is actually
	# (upper - page_size).
	$adj1 = Gtk2::Adjustment->new(0.0, 0.0, 101.0, 0.1, 1.0, 1.0);

	$vscale = Gtk2::VScale->new($adj1);
	scale_set_default_values($vscale);
	$box2->pack_start($vscale, TRUE, TRUE, 0);
	$vscale->show;

	$box3 = Gtk2::VBox->new(FALSE, 10);
	$box2->pack_start($box3, TRUE, TRUE, 0);
	$box3->show;

	# Reuse the same adjustment
	$hscale = Gtk2::HScale->new($adj1);
	$hscale->set_size_request(200, -1);
	scale_set_default_values($hscale);
	$box3->pack_start($hscale, TRUE, TRUE, 0);
	$hscale->show;
	
	# Reuse the same adjustment again
	$scrollbar = Gtk2::HScrollBar->new($adj1);
	# Notice how this causes the scales to always be updated
	# continuously when the scrollbar is moved
	$scrollbar->set_update_policy('continuous');
	$box3->pack_start($scrollbar, TRUE, TRUE, 0);
	$scrollbar->show;
	
	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);
	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	# A checkbutton to control whether the value is displayed or not
	$button = Gtk2::CheckButton->new("Display value on scale widgets");
	$button->set_active(TRUE);
	$button->signal_connect(toggled => \&cb_draw_value);
	$box2->pack_start($button, TRUE, TRUE, 0);
	$button->show;

	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);

	# An option menu to change the position of the value
	$label = Gtk2::Label->new("Scale Value Position:");
	$box2->pack_start($label, FALSE, FALSE, 0);
	$label->show;

	$opt = Gtk2::OptionMenu->new;
	$menu = Gtk2::Menu->new;

	$item = make_menu_item("Top", \&cb_pos_menu_select, 'top');
	$menu->append($item);
	
	$item = make_menu_item("Bottom", \&cb_pos_menu_select, 'bottom');
	$menu->append($item);

	$item = make_menu_item("Left", \&cb_pos_menu_select, 'left');
	$menu->append($item);

	$item = make_menu_item("Right", \&cb_pos_menu_select, 'right');
	$menu->append($item);

	$opt->set_menu($menu);
	$box2->pack_start($opt, TRUE, TRUE, 0);
	$opt->show;

	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);

	# Yet another option menu, this time for the update policy of the
	# scale widgets
	$label = Gtk2::Label->new("Scale Update Policy:");
	$box2->pack_start($label, FALSE, FALSE, 0);
	$label->show;

	$opt = Gtk2::OptionMenu->new;
	$menu = Gtk2::Menu->new;

	$item = make_menu_item("Continuous", \&cb_update_menu_select, 'continuous');
	$menu->append($item);

	$item = make_menu_item("Discontinuous", \&cb_update_menu_select, 'discontinuous');
	$menu->append($item);

	$item = make_menu_item("Delayed", \&cb_update_menu_select, 'delayed');
	$menu->append($item);

	$opt->set_menu($menu);
	$box2->pack_start($opt, TRUE, TRUE, 0);
	$opt->show;

	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);

	# An HScale widget for adjusting the number of digits on the
	# sample scales.
	$label = Gtk2::Label->new("Scale Digits:");
	$box2->pack_start($label, FALSE, FALSE, 0);
	$label->show;

	$adj2 = Gtk2::Adjustment->new(1.0, 0.0, 5.0, 1.0, 1.0, 0.0);
	$adj2->signal_connect(value_changed => \&cb_digits_scale);
	$scale = Gtk2::HScale->new($adj2);
	$scale->set_digits(0);
	$box2->pack_start($scale, TRUE, TRUE, 0);
	$scale->show;

	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	$box2 = Gtk2::HBox->new(FALSE, 10);
	$box2->set_border_width(10);

	# And, one last HScale widget for adjusting the page size of the
	# scrollbar.
	$label = Gtk2::Label->new("Scrollbar Page Size:");
	$box2->pack_start($label, FALSE, FALSE, 0);
	$label->show;

	$adj2 = Gtk2::Adjustment->new(1.0, 1.0, 101.0, 1.0, 1.0, 0.0);
	$adj2->signal_connect(value_changed => \&cb_page_size, $adj1);
	$scale = Gtk2::HScale->new($adj2);
	$scale->set_digits(0);
	$box2->pack_start($scale, TRUE, TRUE, 0);
	$scale->show;
	
	$box1->pack_start($box2, TRUE, TRUE, 0);
	$box2->show;

	$separator = Gtk2::HSeparator->new;
	$box1->pack_start($separator, FALSE, TRUE, 0);
	$separator->show;

	$box2 = Gtk2::VBox->new(FALSE, 10);
	$box2->set_border_width(10);
	$box1->pack_start($box2, FALSE, TRUE, 0);
	$box2->show;

	$button = Gtk2::Button->new("Quit");
	$button->signal_connect(clicked => sub { Gtk2->main_quit; });
	$box2->pack_start($button, TRUE, TRUE, 0);
	$button->can_default(TRUE);
	$button->grab_default;
	$button->show;

	$window->show;
}

create_range_controls();

Gtk2->main;

0;