#!/usr/bin/perl
use warnings;
#use strict;

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 {
     my ($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.
    my $val = $set->value;    
    my $low = ($set->upper) - ($set->page_size);
    my $high = $set->lower;
        
      $set->set_value( clamp($val,$low,$high)  );

    $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;