Balloon(3) User Contributed Perl Documentation Balloon(3)
NAME
Tk::Balloon - pop up help balloons.
SYNOPSIS
use Tk::Balloon;
...
$b = $top->Balloon(-statusbar => $status_bar_widget);
# Normal Balloon:
$b->attach($widget,
-balloonmsg => "Balloon help message",
-statusmsg => "Status bar message");
# Balloon attached to entries in a menu widget:
$b->attach($menu, -state => 'status',
-msg => ['first menu entry',
'second menu entry',
...
],
);
# Balloon attached to individual items in a canvas widget:
$b->attach($canvas, -balloonposition => 'mouse',
-msg => {'item1' => 'msg1',
'tag2' => 'msg2',
...
},
);
# Balloon attached to items in a listbox widget:
$b->attach($listbox, -balloonposition => 'mouse',
-msg => ['first listbox element',
'2nd listbox element',
...
],
);
DESCRIPTION
Balloon provides the framework to create and attach help balloons to
various widgets so that when the mouse pauses over the widget for more
than a specified amount of time, a help balloon is popped up.
Balloons and Menus or Listboxes
If the balloon is attached to a Menu or Listbox widget and the message
arguments are array references, then each element in the array will be
the message corresponding to a menu entry or listbox element. The
balloon message will then be shown for the entry which the mouse pauses
over. Otherwise it is assumed that the balloon is to be attached to the
Menu or Listbox as a whole. You can have separate status and balloon
messages just like normal balloons.
Balloons and Canvases
If the balloon is attached to a Canvas widget and the message arguments
are hash references, then each hash key should correspond to a canvas
item ID or tag and the associated value will correspond to the message
for that canvas item. The balloon message will then be shown for the
current item (the one at the position of the mouse). Otherwise it is
assumed that the balloon is to be attached to the Canvas as a whole.
You can have separate status and balloon messages just like normal
balloons.
Balloons and HLists
If the balloon is attached to a HList widget and the message arguments
are hash references, then each hash key should correspond to a HList
path and the associated value will correspond to the message for that
HList item. The balloon message will then be shown for the current item
(the one at the position of the mouse). Otherwise it is assumed that
the balloon is to be attached to the HList as a whole. You can have
separate status and balloon messages just like normal balloons.
Balloon Position
By default, the balloon pops up at the lower right side of the client.
If it would extend outside the lower screen border, its positioned at
the upper right side. If it would extend outside the right screen
border it's shown on the lower left side of the client. If it would
extend outside both the lower and the right screen border, it's
positioned at the upper left side of the client. Thus, the little arrow
always points to the attached client.
OPTIONS
Balloon accepts all of the options that the Frame widget accepts. In
addition, the following options are also recognized.
-initwait
Specifies the amount of time to wait without activity before
popping up a help balloon. Specified in milliseconds. Defaults to
350 milliseconds. This applies to both the popped up balloon and
the status bar message.
-state
Can be one of 'balloon', 'status', 'both' or 'none' indicating that
the help balloon, status bar help, both or none respectively should
be activated when the mouse pauses over the client widget. Default
is 'both'.
-statusbar
Specifies the widget used to display the status message. This
widget should accept the -text option and is typically a Label. If
the widget accepts the -textvariable option and that option is
defined then it is used instead of the -text option.
-balloonposition
Can be one of 'widget' or 'mouse'. It controls where the balloon
will popup. 'widget' makes the balloon appear at the lower right
corner of the widget it is attached to (default), and 'mouse' makes
the balloon appear below and to the right of the current mouse
position.
-postcommand
This option takes a CODE reference which will be executed before
the balloon and statusbar messages are displayed and should return
a true or false value to indicate whether you want the balloon to
be displayed or not. This also lets you control where the balloon
is positioned by returning a true value that looks like X,Y
(matches this regular expression: "/^(\d+),(\d+)$/"). If the
postcommand returns a value that matches that re then those
coordinates will be used as the position to post the balloon.
Warning: this subroutine should return quickly or the balloon
response will appear slow.
-cancelcommand
This option takes a CODE reference which will be executed before
the balloon and statusbar messages are canceled and should return a
true or false value to indicate whether you want the balloon to be
canceled or not. Warning: this subroutine should return quickly or
the balloon response will appear slow.
-motioncommand
This option takes a CODE reference which will be executed for any
motion event and should return a true or false value to indicate
whether the currently displayed balloon should be canceled
(deactivated). If it returns true then the balloon will definitely
be canceled, if it returns false then it may still be canceled
depending the internal rules. Note: a new balloon may be posted
after the -initwait time interval, use the -postcommand option to
control that behavior. Warning: the subroutine should be extremely
fast or the balloon response will appear slow and consume a lot of
CPU time (it is executed every time the mouse moves over the
widgets the balloon is attached to).
-numscreens
This option accepts an integer 1 or greater. This option should be
used to avoid disjointed balloons across multiple screens in single
logical sceen (SLS) mode. This only currently works in the
horizontal direction. Example: If you are running dual screens in
SLS mode then you would set this value to 2. Default value is 1.
METHODS
The Balloon widget supports only three non-standard methods:
attach(widget, options)
Attaches the widget indicated by widget to the help system. The allowed
options are:
-statusmsg
The argument is the message to be shown on the status bar when the
mouse pauses over this client. If this is not specified, but -msg
is specified then the message displayed on the status bar is the
same as the argument for -msg. If you give it a scalar reference
then it is dereferenced before being displayed. Useful if the
postcommand is used to change the message.
-balloonmsg
The argument is the message to be displayed in the balloon that
will be popped up when the mouse pauses over this client. As with
-statusmsg if this is not specified, then it takes its value from
the -msg specification if any. If neither -balloonmsg nor -msg are
specified, or they are the empty string then no balloon is popped
up instead of an empty balloon. If you give it a scalar reference
then it is dereferenced before being displayed. Useful if the
postcommand is used to change the message.
-msg
The catch-all for -statusmsg and -balloonmsg. This is a convenient
way of specifying the same message to be displayed in both the
balloon and the status bar for the client.
-initwait
-state
-statusbar
-balloonposition
-postcommand
-cancelcommand
-motioncommand
These options allow you to override the balloon's default value for
those option for some of the widgets it is attached to. It accepts
the same values as above and will default to the Balloon's value.
detach(widget)
Detaches the specified widget from the help system.
destroy
Destroys the specified balloon.
ADVERTISED SUBWIDGETS
The balloon label is advertised as "message".
EXAMPLES
See the balloon demo included with the widget demo script that came
with the distribution for examples on various ways to use balloons.
NOTES
Because of the overhead associated with each balloon you create (from
tracking the mouse movement to know when to activate and deactivate
them) you will see the best performance (low CPU consumption) if you
create as few balloons as possible and attach them to as many widgets
as you can. In other words, don't create a balloon for each widget you
want to attach one to.
CAVEATS
Pressing any button will deactivate (cancel) the current balloon, if
one exists. You can usually make the balloon reappear by moving the
mouse a little. Creative use of the 3 command options can help you out
also. If the mouse is over the balloon when a menu is unposted then the
balloon will remain until you move off of it.
BUGS
If using balloons attached to listbox entries or canvas items in a
scrolled widget, then the subwidget have to be used:
$balloon->attach($w->Subwidget("scrolled"), -msg => ...);
AUTHORS
Rajappa Iyer <rsi@earthling.net> did the original coding.
Jason A. Smith <smithj4@rpi.edu> added support for menus and made some
other enhancements.
Slaven Rezic <srezic@cpan.org> added support for canvas items.
Gerhard Petrowitsch <gerhard@petrowitsch.de> added intelligent
positioning
Jack Dunnigan <dunniganj@cpan.org> Made positioning more intelligent
and added support for multiple monitors under single logical screen.
HISTORY
The code and documentation was derived from Balloon.tcl from the Tix4.0
distribution by Ioi Lam and modified by the above mentioned authors.
This code may be redistributed under the same terms as Perl.
perl v5.18.0 2012-01-16 Balloon(3)
perl-Tk 804.030_502 - Generated Mon Aug 12 05:49:08 CDT 2013