Provided by: perl-tk_804.033-2build1_amd64 
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.