| Allegro CL version 8.2 This page is new in 8.2. |
The split-bar
control can
be used to allow the end user to interactively resize multiple tiled
windows panes, or to move and resize groups of widgets.
This is done by creating a split-bar
widget that lies between other sibling
widgets or windows that it should affect. When used to resize window
panes, typically you would leave just enough room between the panes to
insert the split-bar like another tiled pane. (The parent window does
not need to be a dialog, though the split-bar
is always a
dialog-item
.) When used to
move and/or resize groups of widgets instead, there may be additional
space between the groups of widgets, with the split-bar
placed midway in between.
A split-bar
can extend
across its parent window either horizontally or vertically by setting
its orientation property to :horizontal or :vertical.
The simple bar that's drawn for the control can be either visible or
invisible while idle, while under the mouse, or while being dragged,
according to the properties color-when-idle, color-under-mouse, and color-when-dragging. (A split-bar
that's on a form window will always be
visible to facilitate laying out the form, so you would need to run
the form to check the invisibility.)
The control will display a special mouse cursor when the mouse is over
the bar to indicate that a drag can be done when clicking at that
location. This allows the user to find a split-bar
even when the widget itself is
invisible.
You can specify what happens when the user drags
a split-bar
by setting up
simple lists of the widgets or panes that should be resized or moved
as the bar is dragged, if that is sufficient. See
the widgets-to-move and
widgets-to-resize properties.
Otherwise an on-change
function can be used for customized behavior. A split-bar
can resize panes or widgets
continuously during the drag, or only once at the end, according to
its delayed property.
The split-bar
's current
position can be controlled programmatically by setting
the value property.
The widget's value should be a non-negative integer that indicates the
distance of a horizontal split-bar from the top edge of the parent
window's interior, or the distance of a vertical split-bar from the
left edge of the parent window's interior.
When creating a split-bar
programmatically and passing the orientation
argument as :vertical
, you will probably want to
also pass the cursor-name argument as
:vertical-splitbar-cursor
(or the name of a custom
cursor), since it will otherwise default to
:horizontal-splitbar-cursor
. (This is not an issue
when creating a split-bar interactively on a form window.)
The Navigator Dialog includes a split-bar example called Two Window-Panes with a Draggable Split-Bar Widget.
Here are the properties of the split-bar:
The class of widget-window
that is displayed for a split-bar is split-bar-pane
. Typically an application needs
to deal only with the dialog-item class, though if you supply an
on-redisplay function to draw a split-bar
in a custom way, then you draw on
the split-bar-pane
.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page is new in the 8.2 release.
Created 2016.6.21.
| Allegro CL version 8.2 This page is new in 8.2. |