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  4. grid(n)

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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:



  

  
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 RELATIVE PLACEMENT section below), then the command is
      processed in the same way as grid configure.

  

  
The anchor value controls how to place the grid within the master when no
      row/column has any weight. See THE GRID ALGORITHM below for further
      details. The default anchor is nw.

  

  
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 indicated is returned.

  

  
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 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 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 master window and
      index is specified, all the current settings are returned in a list of
      “-option value” pairs.

  

  
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:







  

  
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.

  

  
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 -.

  

  
Insert the slave(s) in the master window given by other. The
      default is the first slave's parent window.

  

  
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.

  

  
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.

  

  
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.

  

  
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.

  

  
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.

  

  
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.

  

  
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 unspecified options for them retain their previous values rather
    than receiving default values.





  

  
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.

  

  
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 elements of the list are
      “-in master” where master is the
      slave's master.

  

  
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.

  

  
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.

  

  
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 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 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 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 master
      window and index is specified, all the current settings are returned in a
      list of “-option value” pairs.

  

  
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.

  

  
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.

  

  
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.

  

  
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 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 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 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 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 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 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 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 xview}
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







  

    8.5
    Tk