NAME
Prima::Widget::place - Geometry manager for fixed or rubber-sheet
placement
SYNOPSIS
$widget->place(option=>value?, option=>value, ...)
$widget->placeForget;
$widget->placeInfo(option=>value?, option=>value, ...);
$widget->geometry( gt::Place);
$master->placeSlaves
DESCRIPTION
The placer is a geometry manager from Tk. It provides simple fixed
placement of windows, where you specify the exact size and location of
one window, called the slave, within another window, called the
$master. The placer also provides rubber-sheet placement, where you
specify the size and location of the slave in terms of the dimensions
of the master, so that the slave changes size and location in response
to changes in the size of the master. Lastly, the placer allows you to
mix these styles of placement so that, for example, the slave has a
fixed width and height but is centered inside the master.
place %OPTIONS
The place method arranges for the placer to manage the geometry of
$slave. The remaining arguments consist of one or more
option=>value pairs that specify the way in which $slave’s geometry
is managed. If the placer is already managing $slave, then the
option=>value pairs modify the configuration for $slave. The place
method returns an empty string as result. The following
option=>value pairs are supported:
in => $master
$master is the reference to the window relative to which
$slave is to be placed. $master must neither be $slave’s
child nor be present in a slaves list that directly or
indirectly refers to the $slave.
If this option isn’t specified then the master defaults to
$slave’s owner.
x => location
Location specifies the x-coordinate within the master
window of the anchor point for $slave widget.
relx => location
Location specifies the x-coordinate within the master
window of the anchor point for $slave widget. In this case
the location is specified in a relative fashion as a
floating-point number: 0.0 corresponds to the left edge of
the master and 1.0 corresponds to the right edge of the
master. Location need not be in the range 0.0-1.0. If
both x and relx are specified for a slave then their values
are summed. For example, "relx=>0.5, x=-2" positions the
left edge of the slave 2 pixels to the left of the center
of its master.
y => location
Location specifies the y-coordinate within the master
window of the anchor point for $slave widget.
rely => location
Location specifies the y-coordinate within the master
window of the anchor point for $slave widget. In this case
the value is specified in a relative fashion as a floating-
point number: 0.0 corresponds to the top edge of the
master and 1.0 corresponds to the bottom edge of the
master. Location need not be in the range 0.0-1.0. If
both y and rely are specified for a slave then their values
are summed. For example, rely=>0.5, x=>3 positions the top
edge of the slave 3 pixels below the center of its master.
anchor => where
Where specifies which point of $slave is to be positioned
at the (x,y) location selected by the x, y, relx, and rely
options. Thus if where is se then the lower-right corner
of $slave’s border will appear at the given (x,y) location
in the master. The anchor position defaults to nw.
width => size
Size specifies the width for $slave. If size is an empty
string, or if no width or relwidth option is specified,
then the width requested internally by the window will be
used.
relwidth => size
Size specifies the width for $slave. In this case the
width is specified as a floating-point number relative to
the width of the master: 0.5 means $slave will be half as
wide as the master, 1.0 means $slave will have the same
width as the master, and so on. If both width and relwidth
are specified for a slave, their values are summed. For
example, relwidth=>1.0, width=>5 makes the slave 5 pixels
wider than the master.
height => size
Size specifies the height for $slave. If size is an empty
string, or if no height or relheight option is specified,
then the height requested internally by the window will be
used.
relheight => size
Size specifies the height for $slave. In this case the
height is specified as a floating-point number relative to
the height of the master: 0.5 means $slave will be half as
high as the master, 1.0 means $slave will have the same
height as the master, and so on. If both height and
relheight are specified for a slave, their values are
summed. For example, relheight=>1.0, height=>-2 makes the
slave 2 pixels shorter than the master.
placeSlaves
The placeSlaves method returns a list of all the slave windows for
which $master is the master. If there are no slaves for $master
then an empty list is returned.
placeForget
The placeForget method causes the placer to stop managing the
geometry of $slave. If $slave isn’t currently managed by the
placer then the method call has no effect.
placeInfo %OPTIONS
In get-mode the placeInfo method returns a list giving the current
configuration of $slave. The list consists of option=>value pairs
in exactly the same form as might be specified to the place method.
If the configuration of a window has been retrieved with placeInfo,
that configuration can be restored later by first using placeInfo
in set-mode and setting geometry to "gt::Place", which is
equivalent to a direct call to place.
Fine points
It is not necessary for the master window to be the owner of the slave
window. This feature is useful in at least two situations. First, for
complex window layouts it means you can create a hierarchy of
subwindows whose only purpose is to assist in the layout of the owner.
The ‘‘real children’’ of the owner (i.e. the windows that are
significant for the application’s user interface) can be children of
the owner yet be placed inside the windows of the geometry-management
hierarchy. This means that the path names of the ‘‘real children’’
don’t reflect the geometry-management hierarchy and users can specify
options for the real children without being aware of the structure of
the geometry-management hierarchy.
A second reason for having a master different than the slave’s owner is
to tie two siblings together. For example, the placer can be used to
force a window always to be positioned centered just below one of its
siblings by specifying the configuration
in=>$sibling, relx=>0.5, rely=>1.0, anchor=>’n’
Whenever the $sibling widget is repositioned in the future, the slave
will be repositioned as well.
Unlike the other geometry managers (such as the packer) the placer does
not make any attempt to manipulate the geometry of the master windows
or the owners of slave windows (i.e. it doesn’t set their requested
sizes).
SEE ALSO
Prima, Prima::Widget
Tk::place Tk::pack