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.so man.macros

.TH grid n 4.1 Tk "Tk Built-In Commands"

.BS

'\" Note:  do not modify the .SH NAME line immediately below!

.SH NAME

grid \- Geometry manager that arranges widgets in a grid

.SH SYNOPSIS

\fBgrid \fIoption arg \fR?\fIarg ...\fR?

.BE

.SH DESCRIPTION

.PP

The \fBgrid\fR 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 \fBgrid\fR command can have any of several forms, depending

on the \fIoption\fR argument:

.TP

\fBgrid \fIslave \fR?\fIslave ...\fR? ?\fIoptions\fR?

If the first argument to \fBgrid\fR is a window name (any value

starting with ``.''), then the command is processed in the same

way as \fBgrid configure\fR.

.TP

\fBgrid bbox \fImaster\fR ?\fIcolumn row\fR? ?\fIcolumn2 row2\fR?

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 \fIcolumn\fP and \fIrow\fP 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 \fIcolumn\fP and \fIrow\fP

arguments are specified, then the bounding box spanning the rows and columns

indicated is returned.

.TP

\fBgrid columnconfigure \fImaster index \fR?\fI\-option value...\fR?

Query or set the column properties of the \fIindex\fP column of the

geometry master, \fImaster\fP.

The valid options are \fB\-minsize\fP, \fB\-weight\fP and \fB-pad\fP.

.VS

If one or more options are provided, then \fIindex\fP may be given as

a list of column indeces to which the configuration options will operate on.

.VE

The \fB\-minsize\fP option sets the minimum size, in screen units,

that will be permitted for this column.

The \fB\-weight\fP 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 \fB-pad\fP 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 an list of "-option value" pairs.

.TP

\fBgrid configure \fIslave \fR?\fIslave ...\fR? ?\fIoptions\fR?

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 \fB\-\fP,  \fBx\fP and \fB^\fP,

can be specified instead of a window name to alter the default

location of a \fIslave\fP, as described in the ``RELATIVE PLACEMENT''

section, below.

The following options are supported:

.RS

.TP

\fB\-column \fIn\fR

Insert the slave so that it occupies the \fIn\fPth 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 \fIgrid\fP, or column "0" if it is the first slave.  For each

\fBx\fP that immediately precedes the \fIslave\fP, the column position

is incremented by one.  Thus the \fBx\fP represents a blank column

for this row in the grid.

.TP

\fB\-columnspan \fIn\fR

Insert the slave so that it occupies \fIn\fP columns in the grid.

The default is one column, unless the window name is followed by a

\fB\-\fP, in which case the columnspan is incremented once for each immediately

following \fB\-\fP.

.TP

\fB\-in \fIother\fR

Insert the slave(s) in the master

window given by \fIother\fR.  The default is the first slave's

parent window.

.TP

\fB\-ipadx \fIamount\fR

The \fIamount\fR 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 \fIamount\fR must be a valid screen distance, such as \fB2\fR or \fB.5c\fR.

It defaults to 0.

.TP

\fB\-ipady \fIamount\fR

The \fIamount\fR 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 \fIamount\fR  defaults to 0.

.TP

\fB\-padx \fIamount\fR

The \fIamount\fR specifies how much horizontal external padding to

leave on each side of the slave(s), in screen units.

The \fIamount\fR defaults to 0.

This space is added outside the slave(s) border.

.TP

\fB\-pady \fIamount\fR

The \fIamount\fR specifies how much vertical external padding to

leave on the top and bottom of the slave(s), in screen units.

The \fIamount\fR defaults to 0.

This space is added outside the slave(s) border.

.TP

\fB\-row \fIn\fR

Insert the slave so that it occupies the \fIn\fPth 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 \fBgrid\fP, or the first unoccupied row if this is the first slave.

.TP

\fB\-rowspan \fIn\fR

Insert the slave so that it occupies \fIn\fP rows in the grid.

The default is one row.  If the next \fBgrid\fP command contains

\fB^\fP characters instead of \fIslaves\fP that line up with the columns

of this \fIslave\fP, then the \fBrowspan\fP of this \fIslave\fP is

extended by one.

.TP

\fB\-sticky \fIstyle\fR

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.

\fIStyle\fR  is a string that contains zero or more of the characters

\fBn\fP, \fBs\fP, \fBe\fP or \fBw\fP.

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 \fBn\fP and \fBs\fP (or

\fBe\fP and \fBw\fP) are specified, the slave will be stretched to fill the entire

height (or width) of its cavity.  The \fBsticky\fP option subsumes the

combination of \fB\-anchor\fP and \fB\-fill\fP that is used by \fBpack\fP.

The default is \fB{}\fP, which causes the slave to be centered in its cavity,

at its requested size.

.LP

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.

.RE

.TP

\fBgrid forget \fIslave \fR?\fIslave ...\fR?

Removes each of the \fIslave\fRs 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.

.TP

\fBgrid info \fIslave\fR

Returns a list whose elements are the current configuration state of

the slave given by \fIslave\fR in the same option-value form that

might be specified to \fBgrid configure\fR.

The first two elements of the list are ``\fB\-in \fImaster\fR'' where

\fImaster\fR is the slave's master.

.TP

\fBgrid location \fImaster x y\fR

Given  \fIx\fP and \fIy\fP values in screen units relative to the master window,

the column and row number at that \fIx\fP and \fIy\fP location is returned.

For locations that are above or to the left of the grid, \fB-1\fP is returned.

.TP

\fBgrid propagate \fImaster\fR ?\fIboolean\fR?

If \fIboolean\fR has a true boolean value such as \fB1\fR or \fBon\fR

then propagation is enabled for \fImaster\fR, which must be a window

name (see ``GEOMETRY PROPAGATION'' below).

If \fIboolean\fR has a false boolean value then propagation is

disabled for \fImaster\fR.

In either of these cases an empty string is returned.

If \fIboolean\fR is omitted then the command returns \fB0\fR or

\fB1\fR to indicate whether propagation is currently enabled

for \fImaster\fR.

Propagation is enabled by default.

.TP

\fBgrid rowconfigure \fImaster index \fR?\fI\-option value...\fR?

Query or set the row properties of the \fIindex\fP row of the

geometry master, \fImaster\fP.

The valid options are \fB\-minsize\fP, \fB\-weight\fP and \fB-pad\fP.

.VS

If one or more options are provided, then \fIindex\fP may be given as

a list of row indeces to which the configuration options will operate on.

.VE

The \fB\-minsize\fP option sets the minimum size, in screen units,

that will be permitted for this row.

The \fB\-weight\fP 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 \fB-pad\fP 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 an list of "-option value" pairs.

.TP

\fBgrid remove \fIslave \fR?\fIslave ...\fR?

Removes each of the \fIslave\fRs 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.

.TP

\fBgrid size \fImaster\fR

Returns the size of the grid (in columns then rows) for \fImaster\fP.

The size is determined either by the \fIslave\fP occupying the largest

row or column, or the largest column or row with a \fBminsize\fP,

\fBweight\fP, or \fBpad\fP that is non-zero.

.TP

\fBgrid slaves \fImaster\fR ?\fI\-option value\fR?

If no options are supplied, a list of all of the slaves in \fImaster\fR

are returned, most recently manages first.

\fIOption\fP can be either \fB\-row\fP or \fB\-column\fP which

causes only the slaves in the row (or column) specified by \fIvalue\fP

to be returned.

.SH "RELATIVE PLACEMENT"

.PP

The \fBgrid\fP 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 \fIslave\fP,

default values are chosen for

\fBcolumn\fP, \fBrow\fP, \fBcolumnspan\fP and \fBrowspan\fP

at the time the \fIslave\fP is managed. The values are chosen

based upon the current layout of the grid, the position of the \fIslave\fP

relative to other \fIslave\fPs in the same grid command, and the presence

of the characters \fB\-\fP, \fB^\fP, and \fB^\fP in \fBgrid\fP

command where \fIslave\fP names are normally expected.

.RS

.TP

\fB\-\fP

This increases the columnspan of the \fIslave\fP to the left.  Several

\fB\-\fP's in a row will successively increase the columnspan. A \fB\-\fP

may not follow a \fB^\fP or a \fBx\fP.

.TP

\fBx\fP

This leaves an empty column between the \fIslave\fP on the left and

the \fIslave\fP on the right.

.TP

\fB^\fP

This extends the \fBrowspan\fP of the \fIslave\fP above the \fB^\fP's

in the grid.  The number of \fB^\fP's in a row must match the number of

columns spanned by the \fIslave\fP above it.

.RE

.SH "THE GRID ALGORITHM"

.PP

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 \fIsticky\fP flag.

.PP

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

\fIminsize\fP for that row or column, or the sum of the \fIpad\fPding

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 \fIweight\fP.  For each

group whose weights are all zero, the additional space is apportioned

equally.

.PP

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.

.SH "GEOMETRY PROPAGATION"

.PP

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 \fBgrid propagate\fR 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.

.SH "RESTRICTIONS ON MASTER WINDOWS"

.PP

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 \fBgrid\fP must have the same master.

.SH "STACKING ORDER"

.PP

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.

.SH CREDITS

.PP

The \fBgrid\fP command is based on ideas taken from the \fIGridBag\fP

geometry manager written by Doug. Stein, and the \fBblt_table\fR geometry

manager, written by George Howlett.

.SH KEYWORDS

geometry manager, location, grid, cell, propagation, size, pack