grid(n) - phpMan

grid(n) Tk Built-In Commands 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 wid-
gets 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 argu-
ment:

grid slave ?slave ...? ?options?
If the first argument to grid is suitable as the first slave argument to grid con-
figure, 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 anchor master ?anchor? |
The anchor value controls how to place the grid within the master when no row/col- |
umn has any weight. See THE GRID ALGORITHM below for further details. The default |
anchor is nw.

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 indi-
cated is returned.

grid columnconfigure master index ?-option value...?
Query or set the column properties of the index column of the geometry master, mas-
ter. 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. Indices may be integers, window names |
or the keyword all. For all the options apply to all columns currently occupied be |
slave windows. For a window name, that window must be a slave of this master and |
the options apply to all columns currently occupied be the slave. The -minsize
option sets the minimum size, in screen units, that will be permitted for this col-
umn. The -weight option (an integer value) sets the relative weight for apportion-
ing 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 lay-
out. 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 pre-
cedes the slave, the column position is incremented by one. Thus the x rep-
resents 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 unspeci-
fied 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 con-
figure. 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 config-
uration options will operate on. Indices may be integers, window names or the key- |
word all. For all the options apply to all rows currently occupied be slave win- |
dows. For a window name, that window must be a slave of this master and the options |
apply to all rows currently occupied be the slave. 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 spa-
ces 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 con-
tained 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 speci-
fied, 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 con-
figuration 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 deter-
mined either by the slave occupying the largest row or column, or the largest col-
umn 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 -,
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 ALGORITHM
The grid geometry manager lays out its slaves in three steps. In the first step, the min-
imum 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 dif-
ferent, 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 config-
ured 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 appor- |
tioned according to the row and column weights. If all of the weights are zero, the lay- |
out is placed within its master according to the anchor value. 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 placed and clipped |
according to the anchor value.

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 hier-
archy 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
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 has not 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.

EXAMPLES
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 yview}
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 .t.txt -weight 1
grid columnconfigure .t .t.txt -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 . "all" -uniform allTheSame