place(n) Tk Built-In Commands place(n)_________________________________________________________________NAMEplace - Geometry manager for fixed or rubber-sheet place-
ment
SYNOPSISplace window option value ?option value ...?
place configure window option value ?option value ...?
place forget window
place info window
place slaves window
_________________________________________________________________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 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.
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 geometry of a slave whose path name
is window. The remaining arguments consist of one or more
option-value pairs that specify the way in which window's
geometry is managed. If the placer is already managing
window, then the option-value pairs modify the configura-
tion 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 rela-
tive to which window is to be placed. Master must
either be window's parent or a descendant of win-
dow'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 specified then the master
defaults to window's parent.
Tk 1
place(n) Tk Built-In Commands place(n)-x location
Location specifies the x-coordinate within the mas-
ter 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 mas-
ter window of the anchor point for window. In this
case the location is specified in a relative fash-
ion 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 cen-
ter of its master.
-y location
Location specifies the y-coordinate within the mas-
ter 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 mas-
ter window of the anchor point for window. 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 speci-
fied 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 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 including
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 includ-
ing its border, if any. If size is an empty
Tk 2
place(n) Tk Built-In Commands place(n)
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 window. In this case
the width is specified as a floating-point number
relative to the width of the master: 0.5 means win-
dow 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_GetPix-
els). 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 master, 1.0
means window will have the same height as the mas-
ter, 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 mas-
ter, inside any border: an option of -x 0 corre-
sponds 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 typ-
ically 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 bor-
ders are ignored: the area of the master is con-
sidered to be its official X area, which includes
any internal border but no external border. A bor-
dermode of ignore is probably not very useful.
Tk 3
place(n) Tk Built-In Commands place(n)
If the same value is specified separately with two differ-
ent 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 manag-
ing the geometry of window. As a side effect of this com-
mand window will be unmapped so that it doesn't appear on
the screen. If window isn't currently 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 configu-
ration of a window has been retrieved with place info,
that configuration 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 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 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
Tk 4
place(n) Tk Built-In Commands place(n)
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 5
