# ruler.pl

use subs qw/ruler_make_tab ruler_move_tab ruler_new_tab ruler_release_tab
	    ruler_select_tab/;
use vars qw/$TOP/;

sub ruler {

    # Create a canvas demonstration consisting of a ruler displays a ruler
    # with tab stops that can be set individually.

    my($demo) = @ARG;
    my $demo_widget = $MW->WidgetDemo(
        -name     => $demo,
        -text     => ['This canvas widget shows a mock-up of a ruler.  You can create tab stops by dragging them out of the well to the right of the ruler.  You can also drag existing tab stops.  If you drag a tab stop far enough up or down so that it turns dim, it will be deleted when you release the mouse button.', qw/-wraplength 5i/],
        -title    => 'Ruler Demonstration',
        -iconname => 'ruler',
    );
    $TOP = $demo_widget->Top;	# get geometry master

    my $c = $TOP->Canvas(qw/-width 14.8c -height 2.5c/);
    $c->pack(qw/-side top -fill x/);

    my %rinfo;			# ruler information hash
    $rinfo{grid} = '.25c';
    $rinfo{left} = $c->fpixels('1c');
    $rinfo{right} = $c->fpixels('13c');
    $rinfo{top} = $c->fpixels('1c');
    $rinfo{bottom} = $c->fpixels('1.5c');
    $rinfo{size} = $c->fpixels('.2c');
    $rinfo{normalStyle} = [qw/-fill black/];
    if ($TOP->depth > 1) {
	$rinfo{activeStyle} = [qw/-fill red -stipple/ => undef];
	$rinfo{deleteStyle} = [
            -fill    => 'red',  
	    -stipple => '@'.Tk->findINC('demos/images/grey.25'),
        ];
    } else {
	$rinfo{activeStyle} = [qw/-fill black -stipple/ => undef];
	$rinfo{deleteStyle} = [
            -fill    => 'black',
            -stipple => '@'.Tk->findINC('demos/images/grey.25'),
        ];
    }

    $c->create(qw/line 1c 0.5c 1c 1c 13c 1c 13c 0.5c -width 1/);
    my $i;
    for ($i = 0; $i < 12; $i++) {
	my $x = $i+1;
	$c->create('line', "$x.c",  '1c', "$x.c",  '0.6c', -width => 1);
	$c->create('line', "$x.25c", '1c', "$x.25c", '0.8c', -width => 1);
	$c->create('line', "$x.5c",  '1c', "$x.5c",  '0.7c', -width => 1);
	$c->create('line', "$x.75c", '1c', "$x.75c", '0.8c', -width => 1);
	$c->create('text', "$x.15c", '.75c',-text => $i, -anchor => 'sw');
    }
    $c->addtag('well', 'withtag', $c->create(qw/rect 13.2c 1c 13.8c 0.5c
        -outline black -fill/, ($c->configure(-bg))[4]));
    $c->addtag('well', 'withtag', ruler_make_tab($c, $c->pixels('13.5c'),
        $c->pixels('.65c'), \%rinfo));

    $c->bind('well', '<1>' => [\&ruler_new_tab, \%rinfo]);
    $c->bind('tab', '<1>' => [\&ruler_select_tab, \%rinfo]);
    $c->Tk::bind('<B1-Motion>' => [\&ruler_move_tab, \%rinfo]);
    $c->Tk::bind('<Any-ButtonRelease-1>', [\&ruler_release_tab, \%rinfo]);

} # end ruler

sub ruler_make_tab {

    my($c, $x, $y, $rinfo) = @ARG;

    return $c->create('polygon', $x, $y, $x+$rinfo->{size}, $y+$rinfo->{size},
	                                 $x-$rinfo->{size}, $y+$rinfo->{size});

} # end ruler_make_tab

sub ruler_move_tab {

    my($c, $rinfo) = @ARG;

    return if not defined $c->find('withtag', 'active');
    my $e = $c->XEvent;
    my($x, $y) = ($e->x, $e->y);
    my $cx = $c->canvasx($x, $rinfo->{grid});
    my $cy = $c->canvasy($y);
    if ($cx < $rinfo->{left}) {
	$cx =  $rinfo->{left};
    }
    if ($cx > $rinfo->{right}) {
	$cx =  $rinfo->{right};
    }
    if (($cy >= $rinfo->{top}) and ($cy <= $rinfo->{bottom})) {
	$cy =  $rinfo->{top} + 2;
	$c->itemconfigure('active', @{$rinfo->{activeStyle}});
    } else {
	$cy =  $cy - $rinfo->{size} - 2;
	$c->itemconfigure('active', @{$rinfo->{deleteStyle}});
    }
    $c->move('active',  $cx-$rinfo->{'x'}, $cy-$rinfo->{'y'});
    $rinfo->{'x'} = $cx;
    $rinfo->{'y'} = $cy;

} # end ruler_move_tab

sub ruler_new_tab {
    
    my($c, $rinfo) = @ARG;

    my $e = $c->XEvent;
    my($x, $y) = ($e->x, $e->y);
    $c->addtag('active', 'withtag', ruler_make_tab($c, $x, $y, $rinfo));
    $c->addtag('tab', 'withtag', 'active');
    $rinfo->{'x'} = $x;
    $rinfo->{'y'} = $y;
    ruler_move_tab($c, $rinfo);

} # end ruler_new_tab

sub ruler_release_tab {

    my($c, $rinfo) = @ARG;

    return if not defined $c->find('withtag', 'active');
    if ($rinfo->{'y'} != $rinfo->{top} + 2) {
	$c->delete('active');
    } else {
	$c->itemconfigure('active', @{$rinfo->{normalStyle}});
	$c->dtag('active');
    }

} # end ruler_release_tab

sub ruler_select_tab {

    my($c, $rinfo) = @ARG;

    my $e = $c->XEvent;
    my($x, $y) = ($e->x, $e->y);
    $rinfo->{'x'} = $c->canvasx($x, $rinfo->{grid});
    $rinfo->{'y'} = $rinfo->{top} + 2;
    $c->addtag('active', 'withtag', 'current');
    $c->itemconfigure('active', @{$rinfo->{activeStyle}});
    $c->raise('active');

} # end ruler_select_tab

1;
