grid(n) Tk Built-In Commands grid(n) ______________________________________________________________________________
NAME
grid - Geometry manager that arranges widgets in a grid
SYNOPSIS
grid option arg ?arg ...?
______________________________________________________________________________
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 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 RELA-
TIVE 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 mas-
ter when no row/column 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 bound-
ing box for that cell is returned, where the top left cell is
numbered from zero. If both column and row arguments are speci-
fied, 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, master. The valid options are -minsize,
-weight, -uniform and -pad. If one or more options are pro-
vided, 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 column. The -weight option (an inte-
ger 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 set-
tings 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 follow-
ing 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
next row after the highest occupied 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 con-
tains ^ 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 dimen-
sions, this option may be used to position (or stretch)
the slave within its cell. Style is a string that con-
tains 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 val-
ues 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 ele-
ments 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 propa-
gation 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, -uni-
form 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. Indices may be integers, window names
or the keyword all. For all the options apply to all rows cur-
rently occupied be slave windows. 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 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 sup-
plied, 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 mas-
ter 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 informa-
tion. 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 num-
ber of columns spanned. 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 num-
ber 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 minimum size needed to fit all of the slaves is com-
puted, 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 row-spans or column-spans 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 col-
umn 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 con-
figured 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 exam-
ple, 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 addi-
tional space is apportioned according to the row and column weights.
If all of the weights are zero, the layout 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 accord-
ing 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 geome-
try 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 mas-
ter 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. Other-
wise 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 man-
ager written by Doug. Stein, and the blt_table geometry manager, writ-
ten 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
SEE ALSO
pack(n), place(n)
KEYWORDS
geometry manager, location, grid, cell, propagation, size, pack
Tk 8.5 grid(n)
tk 8.6.8 - Generated Sat Jan 6 10:54:08 CST 2018