place
place(n) Tk Built-In Commands place(n)
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NAME
place - Geometry manager for fixed or rubber-sheet placement
SYNOPSIS
place window option value ?option value ...?
place configure window option value ?option value ...?
place forget window
place info window
place slaves window
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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 mas-
ter, 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.
If the first argument to the place command is a window path name or
configure then the command arranges for the placer to manage the geome-
try of a slave whose path name is window. The remaining arguments con-
sist of one or more option-value pairs that specify the way in which
window's geometry is managed. If the placer is already managing win-
dow, then the option-value pairs modify the configuration for window.
In this form the place command returns an empty string as result. The
following option-value pairs are supported:
-in master
Master specifes the path name of the window relative to which
window is to be placed. Master must either be window's parent
or a descendant of window's parent. In addition, master and
window must both be descendants of the same top-level window.
These restrictions are necessary to guarantee that window is
visible whenever master is visible. If this option isn't speci-
fied then the master defaults to window's parent.
-x location
Location specifies the x-coordinate within the master window of
the anchor point for window. 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 window. In this case the location is spec-
ified 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 window. 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 window. In this case the value is speci-
fied in a relative fashion as a floating-point number: 0.0 cor-
responds 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 posi-
tions the top edge of the slave 3 pixels below the center of its
master.
-anchor where
Where specifies which point of window 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 window includ-
ing its border, if any. Thus if where is se then the lower-
right corner of window'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 window in screen units (i.e. any of
the forms accepted by Tk_GetPixels). The width will be the
outer width of window including its border, if any. If size is
an empty string, or if no -width or -relwidth option is speci-
fied, then the width requested internally by the window will be
used.
-relwidth size
Size specifies the width for window. In this case the width is
specified as a floating-point number relative to the width of
the master: 0.5 means window will be half as wide as the master,
1.0 means window 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 window in screen units (i.e. any
of the forms accepted by Tk_GetPixels). The height will be the
outer dimension of window 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 window. In this case the height
is specified as a floating-point number relative to the height
of the master: 0.5 means window will be half as high as the mas-
ter, 1.0 means window 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 con-
siders 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 window 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 window 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.
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.
The place slaves command returns a list of all the slave windows for
which window is the master. If there are no slaves for window then an
empty string is returned.
The place forget command causes the placer to stop managing the geome-
try of window. As a side effect of this command window will be
unmapped so that it doesn't appear on the screen. If window isn't cur-
rently managed by the placer then the command has no effect. Place
forget returns an empty string as result.
The place info command returns a list giving the current configuration
of window. The list consists of option-value pairs in exactly the same
form as might be specified to the place configure command. If the con-
figuration of a window has been retrieved with place info, that config-
uration can be restored later by first using place forget to erase any
existing information for the window and then invoking place configure
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 subwin-
dows 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-man-
agement 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 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 win-
dows 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.
KEYWORDS
geometry manager, height, location, master, place, rubber sheet, slave,
width
Tk place(n)
