grid(3tk) Tk Built-In Commands grid(3tk)
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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 container (or container window). The grid command
can have any of several forms, depending on the option argument:
grid window ?window ...? ?options?
If the first argument to grid is suitable as the first window
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 window ?anchor?
The anchor value controls how to place the grid within the con-
tainer window when no row/column has any weight. See THE GRID
ALGORITHM below for further details. The default anchor is nw.
grid bbox window ?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 container 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 window index ?-option value...?
Query or set the column properties of the index column of the
geometry container, window. 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 content windows. For
a window name, that window must be a content of this container
and the options apply to all columns currently occupied be the
content. The -minsize option sets the minimum size, in screen
units, that will be permitted for this column. The -weight op-
tion (an integer value) sets the relative weight for apportion-
ing any extra spaces among columns. A weight of zero (0) indi-
cates the column will not deviate from its requested size. A
column whose weight is two will grow at twice the rate as a col-
umn 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 ALGO-
RITHM 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 man-
ager requests a size from the containing window. If only an op-
tion is specified, with no value, the current value of that op-
tion is returned. If only the container window and index is
specified, all the current settings are returned in a list of
“-option value” pairs.
grid configure window ?window ...? ?options?
The arguments consist of the names of one or more content win-
dows followed by pairs of arguments that specify how to manage
the content. The characters -, x and ^, can be specified in-
stead of a window name to alter the default location of a win-
dow, as described in the RELATIVE PLACEMENT section, below. The
following options are supported:
-column n
Insert the window so that it occupies the nth column in
the grid. Column numbers start with 0. If this option
is not supplied, then the window is arranged just to the
right of previous window specified on this call to grid,
or column “0” if it is the first window. For each x that
immediately precedes the window, the column position is
incremented by one. Thus the x represents a blank column
for this row in the grid.
-columnspan n
Insert the window 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 in-
cremented once for each immediately following -.
-in container
Insert the window(s) in the container window given by
container. The default is the first window's parent win-
dow.
-ipadx amount
The amount specifies how much horizontal internal padding
to leave on each side of the content. This is space is
added inside the content 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 content. This
space is added inside the content border. The amount
defaults to 0.
-padx amount
The amount specifies how much horizontal external padding
to leave on each side of the content, 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 content border.
-pady amount
The amount specifies how much vertical external padding
to leave on the top and bottom of the content, in screen
units. Amount may be a list of two values to specify
padding for top and bottom separately. The amount de-
faults to 0. This space is added outside the content
border.
-row n Insert the content so that it occupies the nth row in the
grid. Row numbers start with 0. If this option is not
supplied, then the content is arranged on the same row as
the previous content specified on this call to grid, or
the next row after the highest occupied row if this is
the first content.
-rowspan n
Insert the content so that it occupies n rows in the
grid. The default is one row. If the next grid command
contains ^ characters instead of content that line up
with the columns of this content, then the rowspan of
this content is extended by one.
-sticky style
If a content's cell is larger than its requested dimen-
sions, this option may be used to position (or stretch)
the content 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 content will “stick” to.
If both n and s (or e and w) are specified, the content
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 content to be centered in its
cavity, at its requested size.
If any of the content is already managed by the geometry manager
then any unspecified options for them retain their previous val-
ues rather than receiving default values.
grid forget window ?window ...?
Removes each of the windows from grid for its container and un-
maps their windows. The content will no longer be managed by
the grid geometry manager. The configuration options for that
window are forgotten, so that if the window is managed once more
by the grid geometry manager, the initial default settings are
used.
grid info window
Returns a list whose elements are the current configuration
state of the content given by window in the same option-value
form that might be specified to grid configure. The first two
elements of the list are “-in container” where container is the
windows's container window.
grid location window x y
Given x and y values in screen units relative to the container
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 window ?boolean?
If boolean has a true boolean value such as 1 or on then propa-
gation is enabled for window, which must be a window name (see
GEOMETRY PROPAGATION below). If boolean has a false boolean
value then propagation is disabled for window. 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 window. Propagation is enabled by de-
fault.
grid rowconfigure window index ?-option value...?
Query or set the row properties of the index row of the geometry
window, window. 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 by content windows. For a window name, that win-
dow must be a content window of this container and the options
apply to all rows currently occupied by the container window.
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 op-
tion 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 win-
dow. If only an option is specified, with no value, the current
value of that option is returned. If only the container window
and index is specified, all the current settings are returned in
a list of “-option value” pairs.
grid remove window ?window ...?
Removes each of the windows from grid for its container and un-
maps their windows. The content will no longer be managed by
the grid geometry manager. However, the configuration options
for that window are remembered, so that if the content window is
managed once more by the grid geometry manager, the previous
values are retained.
grid size container
Returns the size of the grid (in columns then rows) for con-
tainer. The size is determined either by the content occupying
the largest row or column, or the largest column or row with a
-minsize, -weight, or -pad that is non-zero.
grid slaves window ?-option value?
If no options are supplied, a list of all of the content in win-
dow are returned, most recently managed first. Option can be
either -row or -column which causes only the content in the row
(or column) specified by value to be returned. │
grid content window ?-option value? │
Synonym for grid slaves window ?-option value?.
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 content. This permits content to be rearranged, added, or re-
moved without the need to explicitly specify row and column informa-
tion. When no column or row information is specified for a content,
default values are chosen for -column, -row, -columnspan and -rowspan
at the time the content is managed. The values are chosen based upon
the current layout of the grid, the position of the content relative to
other contents in the same grid command, and the presence of the char-
acters -, x, and ^ in grid command where content names are normally ex-
pected.
- This increases the -columnspan of the content to the
left. Several -'s in a row will successively increase
the number of columns spanned. A - may not follow a ^ or
a x, nor may it be the first content argument to grid
configure.
x This leaves an empty column between the content on the
left and the content on the right.
^ This extends the -rowspan of the content above the ^'s in
the grid. The number of ^'s in a row must match the num-
ber of columns spanned by the content above it.
THE GRID ALGORITHM
The grid geometry manager lays out its content in three steps. In the
first step, the minimum size needed to fit all of the content is com-
puted, then (if propagation is turned on), a request is made of the
container window to become that size. In the second step, the re-
quested size is compared against the actual size of the container. If
the sizes are different, then spaces is added to or taken away from the
layout as needed. For the final step, each content 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 content 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 content, whichever is greater. After that the rows
or columns in each uniform group adapt to each other. Then the content
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 ac-
commodate these content, 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 al-
located 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 config-
ured 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 containers whose size is larger than the requested layout, the ad-
ditional space is apportioned according to the row and column weights.
If all of the weights are zero, the layout is placed within its con-
tainer according to the anchor value. For containers 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 container must
be to just exactly meet the needs of its content, and it sets the re-
quested width and height of the container 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 containers. If propa-
gation is disabled then grid will not set the requested width and
height of the container window. This may be useful if, for example,
you wish for a container window to have a fixed size that you specify.
RESTRICTIONS ON CONTAINER WINDOWS
The container for each content must either be the content's parent (the
default) or a descendant of the content's parent. This restriction is
necessary to guarantee that the content can be placed over any part of
its container that is visible without danger of the content being
clipped by its parent. In addition, all content in one call to grid
must have the same container.
STACKING ORDER
If the container for a content is not its parent then you must make
sure that the content is higher in the stacking order than the con-
tainer. Otherwise the container will obscure the content and it will
appear as if the content has not been managed correctly. The easiest
way to make sure the content is higher than the container is to create
the container 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 -textvariable foo ; set foo "Hello World!"
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(3tk), place(3tk)
KEYWORDS
geometry manager, location, grid, cell, propagation, size, pack
Tk 8.5 grid(3tk)
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