DragonFly On-Line Manual Pages
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 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
RELATIVE 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
container 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
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 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
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 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
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 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
windows followed by pairs of arguments that specify how to
manage the content. The characters -, x and ^, can be
specified instead of a window name to alter the default location
of a window, 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
incremented 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
window.
-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
defaults 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
dimensions, 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
values rather than receiving default values.
grid forget window ?window ...?
Removes each of the windows from grid for its container and
unmaps 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
propagation 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 default.
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,
-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. Indices may be integers,
window names or the keyword all. For all the options apply to
all rows currently occupied by content windows. For a window
name, that window 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 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 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
unmaps 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
container. 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
window 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
removed without the need to explicitly specify row and column
information. 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 characters -, x, and ^ in grid command where content names are
normally expected.
- 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
number 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
computed, then (if propagation is turned on), a request is made of the
container window to become that size. In the second step, the
requested 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
accommodate these content, 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 containers 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 placed within
its container 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
requested 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
propagation 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
container. 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
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 -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(n), place(n)
KEYWORDS
geometry manager, location, grid, cell, propagation, size, pack
Tk 8.5 grid(n)