grid(n) Tk (4.1) grid(n)
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NAME
grid - Geometry manager that arranges widgets in a grid
SYNOPSIS
grid option arg ?arg ...?
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DESCRIPTION
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 a window name (any
value starting with ``.''), 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 and -pad. If one or more options are |
provided, then index may be given as a list of column |
indeces 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 -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
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grid(n) Tk (4.1) grid(n)
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 an 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 on the top and bottom of the
slave(s). This space is added inside the slave(s)
border. The amount defaults to 0.
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grid(n) Tk (4.1) grid(n)-padx amount
The amount specifies how much horizontal external
padding to leave on each side of the slave(s), in
screen units. 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. 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
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grid(n) Tk (4.1) grid(n)
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 and -pad. If one or more options are |
provided, then index may be given as a list of row |
indeces 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 -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
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grid(n) Tk (4.1) grid(n)
returned in an 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.
RELATIVE PLACEMENT
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 -, ^, 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.
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 ALGORITHM
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grid(n) Tk (4.1) grid(n)
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. 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.
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 there minimum sizes, the layout is clipped on the bottom
and right.
GEOMETRY PROPAGATION
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.
RESTRICTIONS ON MASTER WINDOWS
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grid(n) Tk (4.1) grid(n)
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.
STACKING ORDER
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.
CREDITS
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.
KEYWORDS
geometry manager, location, grid, cell, propagation, size,
pack
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