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 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.
- $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.
-option may have any of the values accepted by the placeConfigure
method.
The place method returns $slave.
- $slave->placeConfigure?(-option=>value?,
-option=>value, ...?)?
- Query or modify the geometry options of the
$slave . If no option is specified, this method
returns a list describing the available options (see Tk_ConfigureInfo for
information on the format of this list). If option is specified with no
value, then the command returns a list describing the one named option
(this list will be identical to the corresponding sublist of the value
returned if no option is specified). If one or more option-value pairs are
specified, then the method modifies the given option(s) to have the given
value(s); in this case the command returns "undef".
The following -option=>value pairs are supported:
- -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.
- -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 specified 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 useful.
- -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.
- -in => $master
- $master is the reference to the window
relative 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 necessary to guarantee that $slave is visible
whenever $master is visible. If this option isn't
specified then the master defaults to $slave's
parent.
- -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.
- -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.
- -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.
- -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.
- -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.
- -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.
- -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.
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->placeForget
- The placeForget method causes the placer to stop
managing 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
currently 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.
- $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.
If the configuration 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 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',
-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