place(3)
NAME
Tk::place - Geometry manager for fixed or rubber-sheet
placement
SYNOPSIS
$widget->place?(-option=>value?, -option=>value, ...)? $widget->placeForget $widget->placeInfo $master->placeSlaves
DESCRIPTION
The placer is a geometry manager for Tk. It provides sim
ple 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 dimen
sions 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.
- $slave->place?(-option=>value?, -option=>value, ...?)?
- 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 sup ported: - -in => $master
$master is the reference to the window rela
tive to which $slave is to be placed. $master must either be $slave's parent or a descendant of $slave's parent. In addition, $master and $slave must both be descendants of the same
top-level window. These restrictions are nec
essary to guarantee that $slave is visible
whenever $master is visible. If this option isn't specified then the master defaults to
$slave's parent. - -x => location
- Location specifies the x-coordinate within the
master window of the anchor point for $slave
widget. The location is specified in screen
units (i.e. any of the forms accepted by
Tk_GetPixels) and need not lie within the bounds of the master window. - -relx => location
- Location specifies the x-coordinate within the
master window of the anchor point for $slave
widget. In this case the location is speci
fied 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. The location is specified in screen
units (i.e. any of the forms accepted by
Tk_GetPixels) and need not lie within the bounds of the master window. - -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 num
ber: 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 spec ified for a slave then their values are
summed. For example, -rely=>0.5, -x=>3 posi tions 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. The anchor point is in terms of the outer area of
$slave including its border, if any. 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 in screen
units (i.e. any of the forms accepted by
Tk_GetPixels). The width will be the outer width of $slave including its border, if any. 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 floatingpoint number relative to the width of the mas
ter: 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 in screen
units (i.e. any of the forms accepted by
Tk_GetPixels). The height will be the outer dimension of $slave including its border, if
any. 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 floatingpoint 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. - -bordermode => mode
- Mode determines the degree to which borders
within the master are used in determining the
placement of the slave. The default and most
common value is inside. In this case the
placer considers the area of the master to be
the innermost area of the master, inside any
border: an option of -x=>0 corresponds to an
x-coordinate just inside the border and an
option of -relwidth=>1.0 means $slave will fill the area inside the master's border. If
mode is outside then the placer considers the area of the master to include its border; this
mode is typically used when placing $slave
outside its master, as with the options -x=>0,
-y=>0, -anchor=>ne. Lastly, mode may be spec ified as ignore, in which case borders are
ignored: the area of the master is considered
to be its official X area, which includes any
internal border but no external border. A
bordermode of ignore is probably not very use
ful. - If the same value is specified separately with
two different options, such as -x and -relx, then the most recent option is used and the
older one is ignored. - $slave->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.
- $slave->placeForget
- The placeForget method causes the placer to stop man
aging the geometry of $slave. As a side effect of
this method call $slave will be unmapped so that it
doesn't appear on the screen. If $slave isn't cur
rently managed by the placer then the method call has
no effect. placeForget returns an empty string as result. - $slave->placeInfo
- The placeInfo method returns a list giving the current
configuration of $slave. The list consists of
-option=>value pairs in exactly the same form as might be specified to the place method. If the configura
tion of a window has been retrieved with placeInfo, that configuration can be restored later by first
using placeForget to erase any existing information for the window and then invoking place with the saved
information.
FINE POINTS
It is not necessary for the master window to be the parent
of the slave window. This feature is useful in at least
two situations. First, for complex window layouts it
means you can create a hierarchy of subwindows whose only
purpose is to assist in the layout of the parent. The
``real children'' of the parent (i.e. the windows that are
significant for the application's user interface) can be
children of the parent yet be placed inside the windows of
the geometry-management hierarchy. This means that the
path names of the ``real children'' don't reflect the
geometry-management hierarchy and users can specify
options for the real children without being aware of the
structure of the geometry-management hierarchy.
- A second reason for having a master different than the
slave's parent is to tie two siblings together. For exam
ple, the placer can be used to force a window always to be
positioned centered just below one of its siblings by
specifying the configuration - -in=>$sibling, -relx=>0.5, -rely=>1.0, -anchor=>'n',
- -bordermode=>'outside'
- Whenever the $sibling widget is repositioned in the
future, the slave will be repositioned as well. - Unlike many other geometry managers (such as the packer)
the placer does not make any attempt to manipulate the
geometry of the master windows or the parents of slave
windows (i.e. it doesn't set their requested sizes). To
control the sizes of these windows, make them windows like
frames and canvases that provide configuration options for
this purpose.
SEE ALSO
Tk::form Tk::grid Tk::pack
KEYWORDS
- geometry manager, height, location, master, place, rubber
sheet, slave, width