grid(n) manual page
Table of Contents
grid - Geometry manager that arranges widgets
in a grid
grid option arg ?arg ...?
The grid command is
used to communicate with the grid geometry manager that arranges widgets
in rows and columns inside of another window, called the geometry master
(or master window). The grid command can have any of several forms, depending
on the option argument:
- grid slave ?slave ...? ?options?
- If the first argument
to grid is suitable as the first slave argument to grid configure, either
a window name (any value starting with .) or one of the characters x or
^ (see the RELATIVE PLACEMENT section below), then the command is processed
in the same way as grid configure.
- grid bbox master ?column row? ?column2
row2?
- With no arguments, the bounding box (in pixels) of the grid is returned.
The return value consists of 4 integers. The first two are the pixel offset
from the master window (x then y) of the top-left corner of the grid, and
the second two integers are the width and height of the grid, also in pixels.
If a single column and row is specified on the command line, then the
bounding box for that cell is returned, where the top left cell is numbered
from zero. If both column and row arguments are specified, then the bounding
box spanning the rows and columns indicated is returned.
- grid columnconfigure
master index ?-option value...?
- Query or set the column properties of the index
column of the geometry master, master. The valid options are -minsize, -weight,
-uniform and -pad. If one or more options are provided, then index may be
given as a list of column indices to which the configuration options will
operate on. The -minsize option sets the minimum size, in screen units, that
will be permitted for this column. The -weight option (an integer value)
sets the relative weight for apportioning any extra spaces among columns.
A weight of zero (0) indicates the column will not deviate from its requested
size. A column whose weight is two will grow at twice the rate as a column
of weight one when extra space is allocated to the layout. The -uniform option,
when a non-empty value is supplied, places the column in a uniform group
with other columns that have the same value for -uniform. The space for
columns belonging to a uniform group is allocated so that their sizes are
always in strict proportion to their -weight values. See THE GRID ALGORITHM
below for further details. The -pad option specifies the number of screen
units that will be added to the largest window contained completely in
that column when the grid geometry manager requests a size from the containing
window. If only an option is specified, with no value, the current value
of that option is returned. If only the master window and index is specified,
all the current settings are returned in a list of "-option value" pairs.
- grid configure slave ?slave ...? ?options?
- The arguments consist of the names
of one or more slave windows followed by pairs of arguments that specify
how to manage the slaves. The characters -, x and ^, can be specified instead
of a window name to alter the default location of a slave, as described
in the RELATIVE PLACEMENT section, below. The following options are supported:
- -column n
- Insert the slave so that it occupies the nth column in the grid.
Column numbers start with 0. If this option is not supplied, then the slave
is arranged just to the right of previous slave specified on this call
to grid, or column "0" if it is the first slave. For each x that immediately
precedes the slave, the column position is incremented by one. Thus the
x represents a blank column for this row in the grid.
- -columnspan n
- Insert
the slave so that it occupies n columns in the grid. The default is one
column, unless the window name is followed by a -, in which case the columnspan
is incremented once for each immediately following -.
- -in other
- Insert the
slave(s) in the master window given by other. The default is the first
slave’s parent window.
- -ipadx amount
- The amount specifies how much horizontal
internal padding to leave on each side of the slave(s). This is space is
added inside the slave(s) border. The amount must be a valid screen distance,
such as 2 or .5c. It defaults to 0.
- -ipady amount
- The amount specifies how
much vertical internal padding to leave on the top and bottom of the slave(s).
This space is added inside the slave(s) border. The amount defaults to
0.
- -padx amount
- The amount specifies how much horizontal external padding
to leave on each side of the slave(s), in screen units. Amount may be a
list of two values to specify padding for left and right separately. The
amount defaults to 0. This space is added outside the slave(s) border.
- -pady
amount
- The amount specifies how much vertical external padding to leave
on the top and bottom of the slave(s), in screen units. Amount may be a
list of two values to specify padding for top and bottom separately. The
amount defaults to 0. This space is added outside the slave(s) border.
- -row
n
- Insert the slave so that it occupies the nth row in the grid. Row numbers
start with 0. If this option is not supplied, then the slave is arranged
on the same row as the previous slave specified on this call to grid, or
the first unoccupied row if this is the first slave.
- -rowspan n
- Insert the
slave so that it occupies n rows in the grid. The default is one row. If
the next grid command contains ^ characters instead of slaves that line
up with the columns of this slave, then the rowspan of this slave is extended
by one.
- -sticky style
- If a slave’s cell is larger than its requested dimensions,
this option may be used to position (or stretch) the slave within its cell.
Style is a string that contains zero or more of the characters n, s, e
or w. The string can optionally contains spaces or commas, but they are
ignored. Each letter refers to a side (north, south, east, or west) that
the slave will "stick" to. If both n and s (or e and w) are specified,
the slave will be stretched to fill the entire height (or width) of its
cavity. The sticky option subsumes the combination of -anchor and -fill that
is used by pack. The default is {}, which causes the slave to be centered
in its cavity, at its requested size.
If any of the slaves are already managed
by the geometry manager then any unspecified options for them retain their
previous values rather than receiving default values.
- grid forget slave
?slave ...?
- Removes each of the slaves from grid for its master and unmaps
their windows. The slaves will no longer be managed by the grid geometry
manager. The configuration options for that window are forgotten, so that
if the slave is managed once more by the grid geometry manager, the initial
default settings are used.
- grid info slave
- Returns a list whose elements
are the current configuration state of the slave given by slave in the
same option-value form that might be specified to grid configure. The first
two elements of the list are ‘‘-in master’’ where master is the slave’s master.
- grid location master x y
- Given x and y values in screen units relative
to the master window, the column and row number at that x and y location
is returned. For locations that are above or to the left of the grid, -1
is returned.
- grid propagate master ?boolean?
- If boolean has a true boolean
value such as 1 or on then propagation is enabled for master, which must
be a window name (see GEOMETRY PROPAGATION below). If boolean has a false
boolean value then propagation is disabled for master. In either of these
cases an empty string is returned. If boolean is omitted then the command
returns 0 or 1 to indicate whether propagation is currently enabled for
master. Propagation is enabled by default.
- grid rowconfigure master index
?-option value...?
- Query or set the row properties of the index row of the
geometry master, master. The valid options are -minsize, -weight, -uniform
and -pad. If one or more options are provided, then index may be given as
a list of row indices to which the configuration options will operate
on. The -minsize option sets the minimum size, in screen units, that will
be permitted for this row. The -weight option (an integer value) sets the
relative weight for apportioning any extra spaces among rows. A weight of
zero (0) indicates the row will not deviate from its requested size. A
row whose weight is two will grow at twice the rate as a row of weight
one when extra space is allocated to the layout. The -uniform option, when
a non-empty value is supplied, places the row in a uniform group with other
rows that have the same value for -uniform. The space for rows belonging
to a uniform group is allocated so that their sizes are always in strict
proportion to their -weight values. See THE GRID ALGORITHM below for further
details. The -pad option specifies the number of screen units that will be
added to the largest window contained completely in that row when the grid
geometry manager requests a size from the containing window. If only an
option is specified, with no value, the current value of that option is
returned. If only the master window and index is specified, all the current
settings are returned in a list of "-option value" pairs.
- grid remove slave
?slave ...?
- Removes each of the slaves from grid for its master and unmaps
their windows. The slaves will no longer be managed by the grid geometry
manager. However, the configuration options for that window are remembered,
so that if the slave is managed once more by the grid geometry manager,
the previous values are retained.
- grid size master
- Returns the size of the
grid (in columns then rows) for master. The size is determined either by
the slave occupying the largest row or column, or the largest column or
row with a minsize, weight, or pad that is non-zero.
- grid slaves master
?-option value?
- If no options are supplied, a list of all of the slaves
in master are returned, most recently manages first. Option can be either
-row or -column which causes only the slaves in the row (or column) specified
by value to be returned.
The grid command contains a limited
set of capabilities that permit layouts to be created without specifying
the row and column information for each slave. This permits slaves to
be rearranged, added, or removed without the need to explicitly specify
row and column information. When no column or row information is specified
for a slave, default values are chosen for column, row, columnspan and
rowspan at the time the slave is managed. The values are chosen based upon
the current layout of the grid, the position of the slave relative to other
slaves in the same grid command, and the presence of the characters -, x,
and ^ in grid command where slave names are normally expected.
- -
- This increases
the columnspan of the slave to the left. Several -’s in a row will successively
increase the columnspan. A - may not follow a ^ or a x, nor may it be the
first slave argument to grid configure.
- x
- This leaves an empty column between
the slave on the left and the slave on the right.
- ^
- This extends the rowspan
of the slave above the ^’s in the grid. The number of ^’s in a row must match
the number of columns spanned by the slave above it.
The
grid geometry manager lays out its slaves in three steps. In the first step,
the minimum size needed to fit all of the slaves is computed, then (if
propagation is turned on), a request is made of the master window to become
that size. In the second step, the requested size is compared against the
actual size of the master. If the sizes are different, then spaces is added
to or taken away from the layout as needed. For the final step, each slave
is positioned in its row(s) and column(s) based on the setting of its sticky
flag.
To compute the minimum size of a layout, the grid geometry manager
first looks at all slaves whose columnspan and rowspan values are one,
and computes the nominal size of each row or column to be either the minsize
for that row or column, or the sum of the padding plus the size of the
largest slave, whichever is greater. After that the rows or columns in
each uniform group adapt to each other. Then the slaves whose rowspans
or columnspans are greater than one are examined. If a group of rows or
columns need to be increased in size in order to accommodate these slaves,
then extra space is added to each row or column in the group according
to its weight. For each group whose weights are all zero, the additional
space is apportioned equally.
When multiple rows or columns belong to a
uniform group, the space allocated to them is always in proportion to their
weights. (A weight of zero is considered to be 1.) In other words, a row
or column configured with -weight 1 -uniform a will have exactly the same
size as any other row or column configured with -weight 1 -uniform a. A row
or column configured with -weight 2 -uniform b will be exactly twice as
large as one that is configured with -weight 1 -uniform b.
More technically,
each row or column in the group will have a size equal to k*weight for
some constant k. The constant k is chosen so that no row or column becomes
smaller than its minimum size. For example, if all rows or columns in a
group have the same weight, then each row or column will have the same
size as the largest row or column in the group.
For masters whose size is
larger than the requested layout, the additional space is apportioned according
to the row and column weights. If all of the weights are zero, the layout
is centered within its master. For masters whose size is smaller than the
requested layout, space is taken away from columns and rows according to
their weights. However, once a column or row shrinks to its minsize, its
weight is taken to be zero. If more space needs to be removed from a layout
than would be permitted, as when all the rows or columns are at their minimum
sizes, the layout is clipped on the bottom and right.
The
grid geometry manager normally computes how large a master must be to just
exactly meet the needs of its slaves, and it sets the requested width and
height of the master to these dimensions. This causes geometry information
to propagate up through a window hierarchy to a top-level window so that
the entire sub-tree sizes itself to fit the needs of the leaf windows. However,
the grid propagate command may be used to turn off propagation for one
or more masters. If propagation is disabled then grid will not set the requested
width and height of the master window. This may be useful if, for example,
you wish for a master window to have a fixed size that you specify.
The master for each slave must either be the slave’s parent
(the default) or a descendant of the slave’s parent. This restriction is
necessary to guarantee that the slave can be placed over any part of its
master that is visible without danger of the slave being clipped by its
parent. In addition, all slaves in one call to grid must have the same master.
If the master for a slave is not its parent then you must
make sure that the slave is higher in the stacking order than the master.
Otherwise the master will obscure the slave and it will appear as if the
slave hasn’t been managed correctly. The easiest way to make sure the slave
is higher than the master is to create the master window first: the most
recently created window will be highest in the stacking order.
The
grid command is based on ideas taken from the GridBag geometry manager
written by Doug. Stein, and the blt_table geometry manager, written by George
Howlett.
A toplevel window containing a text widget and two scrollbars:
# Make the widgets
toplevel .t
text .t.txt -wrap none -xscroll {.t.h set} -yscroll {.t.v set}
scrollbar .t.v -orient vertical -command {.t.txt xview}
scrollbar .t.h -orient horizontal -command {.t.txt xview}
# Lay them out
grid .t.txt .t.v -sticky nsew
grid .t.h -sticky nsew
# Tell the text widget to take all the extra room
grid rowconfigure .t 0 -weight 1
grid columnconfigure .t 0 -weight 1
Three widgets of equal width, despite their different "natural" widths:
button .b -text "Foo"
entry .e -variable foo
label .l -text "This is a fairly long piece of text"
grid .b .e .l -sticky ew
grid columnconfigure . {0 1 2} -uniform allTheSame
pack(n)
, place(n)
geometry manager, location, grid, cell,
propagation, size, pack
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