Prima::ScrollBar - standard scroll bars class

The class Prima::ScrollBar implements both vertical and horizontal scrollbars in Prima. This is a purely Perl class without any C-implemented parts except those inherited from Prima::Widget.

	use Prima::ScrollBar;

	my $sb = Prima::ScrollBar-> create( owner => $group, %rest_of_profile);
	my $sb = $group-> insert( 'ScrollBar', %rest_of_profile);

	my $isAutoTrack = $sb-> autoTrack;
	$sb-> autoTrack( $yesNo);

	my $val = $sb-> value;
	$sb-> value( $value);

	my $min = $sb-> min;
	my $max = $sb-> max;
	$sb-> min( $min);
	$sb-> max( $max);
	$sb-> set_bounds( $min, $max);

	my $step = $sb-> step;
	my $pageStep = $sb-> pageStep;
	$sb-> step( $step);
	$sb-> pageStep( $pageStep);

	my $partial = $sb-> partial;
	my $whole = $sb-> whole;
	$sb-> partial( $partial);
	$sb-> whole( $whole);
	$sb-> set_proportion( $partial, $whole);

	my $size = $sb-> minThumbSize;
	$sb-> minThumbSize( $size);

	my $isVertical = $sb-> vertical;
	$sb-> vertical( $yesNo);

	my ($width,$height) = $sb-> get_default_size;

autoTrack BOOLEAN

Tells the widget if it should send Change notification during mouse tracking events. Generally it should only be set to 0 on very slow computers.

Default value is 1 (logical true).

growMode INTEGER

Default value is gm::GrowHiX, i.e. the scrollbar will try to maintain the constant distance from its right edge to its owner's right edge as the owner changes its size. This is useful for horizontal scrollbars.

height INTEGER

Default value is $Prima::ScrollBar::stdMetrics[1], which is an operating system dependent value determined with a call to Prima::Application-> get_default_scrollbar_metrics. The height is affected because by default the horizontal ScrollBar will be created.

max INTEGER

Sets the upper limit for value.

Default value: 100.

min INTEGER

Sets the lower limit for value.

Default value: 0

minThumbSize INTEGER

A minimal thumb breadth in pixels. The thumb cannot have main dimension lesser than this.

Default value: 21

pageStep INTEGER

This determines the increment/decrement to value during "page"-related operations, for example clicking the mouse on the strip outside the thumb, or pressing PgDn or PgUp.

Default value: 10

partial INTEGER

This tells the scrollbar how many of imaginary units the thumb should occupy. See whole below.

Default value: 10

selectable BOOLEAN

Default value is 0 (logical false). If set to 1 the widget receives keyboard focus; when in focus, the thumb is blinking.

step INTEGER

This determines the minimal increment/decrement to value during mouse/keyboard interaction.

Default value is 1.

value INTEGER

A basic scrollbar property; reflects the imaginary position between min and max, which corresponds directly to the position of the thumb.

Default value is 0.

vertical BOOLEAN

Determines the main scrollbar style. Set this to 1 when the scrollbar style is vertical, 0 - horizontal. The property can be changed at run-time, so the scrollbars can morph from horizontal to vertical and vice versa.

Default value is 0 (logical false).

whole INTEGER

This tells the scrollbar how many of imaginary units correspond to the whole length of the scrollbar. This value has nothing in common with min and max. You may think of the combination of partial and whole as of the proportion between the visible size of something (document, for example) and the whole size of that "something". Useful to struggle against infamous "bird" size of Windows scrollbar thumbs.

Default value is 100.

get_default_size

Returns two integers, the default platform dependant width of a vertical scrollbar and height of a horizontal scrollbar.

Change

The Change notification is sent whenever the thumb position of scrollbar is changed, subject to a certain limitations when autoTrack is 0. The notification conforms the general Prima rule: it is sent when appropriate, regardless to whether this was a result of user interaction, or a side effect of some method programmer has called.

Track

If autoTrack is 0, called when the user changes the thumb position by the mouse instead of Change.

	use Prima;
	use Prima::Application name => 'ScrollBar test';
	use Prima::ScrollBar;

	my $w = Prima::Window-> create(
		text => 'ScrollBar test',
		size => [300,200]);

	my $sb = $w-> insert( ScrollBar =>
		width => 280,
		left => 10,
		bottom => 50,
		onChange => sub {
			$w-> text( $_[0]-> value);
		});

	run Prima;

Prima, Prima::Widget, Prima::IntUtils, examples/rtc.pl, examples/scrolbar.pl

Dmitry Karasik <dk@plab.ku.dk>, Anton Berezin <tobez@plab.ku.dk> - documentation