1grid(3)               User Contributed Perl Documentation              grid(3)
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NAME

6       Tk::grid - Geometry manager that arranges widgets in a grid
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SYNOPSIS

9           $widget->grid?(?widget ...,? ?arg ?...>?)?
10
11           $widget->gridOption?(arg ?,arg ...?)?
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DESCRIPTION

14       The grid method is used to communicate with the grid geometry manager
15       that arranges widgets in rows and columns inside of another window,
16       called the geometry master (or master window).  The grid method can
17       have any of several forms, depending on the option argument:
18
19       $slave->grid(?$slave, ...??, options?)
20           The arguments consist of the optional references to more slave
21           windows followed by pairs of arguments that specify how to manage
22           the slaves.  The characters -,  x and ^, can be specified instead
23           of a window reference to alter the default location of a $slave, as
24           described in "RELATIVE PLACEMENT", below.
25
26           If any of the slaves are already managed by the geometry manager
27           then any unspecified options for them retain their previous values
28           rather than receiving default values.
29
30           The following options are supported:
31
32           -column => n
33                   Insert the $slave so that it occupies the nth column in the
34                   grid.  Column numbers start with 0.  If this option is not
35                   supplied, then the $slave is arranged just to the right of
36                   previous slave specified on this call to grid, or column
37                   "0" if it is the first slave.  For each x that immediately
38                   precedes the $slave, the column position is incremented by
39                   one.  Thus the x represents a blank column for this row in
40                   the grid.
41
42           -columnspan => n
43                   Insert the slave so that it occupies n columns in the grid.
44                   The default is one column, unless the window name is
45                   followed by a -, in which case the columnspan is
46                   incremented once for each immediately following -.
47
48           -in => $other
49                   Insert the slave(s) in the master window given by $other.
50                   The default is the first slave's parent window.
51
52           -ipadx => amount
53                   The amount specifies how much horizontal internal padding
54                   to leave on each side of the slave(s).  This is space is
55                   added inside the slave(s) border.  The amount must be a
56                   valid screen distance, such as 2 or '.5c'.  It defaults to
57                   0.
58
59           -ipady => amount
60                   The amount specifies how much vertical internal padding to
61                   leave on on the top and bottom of the slave(s).  This space
62                   is added inside the slave(s) border.  The amount  defaults
63                   to 0.
64
65           -padx => amount
66                   The amount specifies how much horizontal external padding
67                   to leave on each side of the slave(s), in screen units.
68                   The amount defaults to 0.  This space is added outside the
69                   slave(s) border.
70
71           -pady => amount
72                   The amount specifies how much vertical external padding to
73                   leave on the top and bottom of the slave(s), in screen
74                   units.  The amount defaults to 0.  This space is added
75                   outside the slave(s) border.
76
77           -row => n
78                   Insert the slave so that it occupies the nth row in the
79                   grid.  Row numbers start with 0.  If this option is not
80                   supplied, then the slave is arranged on the same row as the
81                   previous slave specified on this call to grid, or the first
82                   unoccupied row if this is the first slave.
83
84           -rowspan => n
85                   Insert the slave so that it occupies n rows in the grid.
86                   The default is one row.  If the next grid method contains ^
87                   characters instead of $slaves that line up with the columns
88                   of this $slave, then the rowspan of this $slave is extended
89                   by one.
90
91           -sticky => style
92                   If a slave's cell is larger than its requested dimensions,
93                   this option may be used to position (or stretch) the slave
94                   within its cell.  Style  is a string that contains zero or
95                   more of the characters n, s, e or w.  The string can
96                   optionally contain spaces or commas, but they are ignored.
97                   Each letter refers to a side (north, south, east, or west)
98                   that the slave will "stick" to.  If both n and s (or e and
99                   w) are specified, the slave will be stretched to fill the
100                   entire height (or width) of its cavity.  The sticky option
101                   subsumes the combination of -anchor and -fill that is used
102                   by pack.  The default is '', which causes the slave to be
103                   centered in its cavity, at its requested size.
104
105       $master->gridBbox(?column, row,? ?column2, row2?)
106           With no arguments, the bounding box (in pixels) of the grid is
107           returned.  The return value consists of 4 integers.  The first two
108           are the pixel offset from the master window (x then y) of the top-
109           left corner of the grid, and the second two integers are the width
110           and height of the grid, also in pixels.  If a single column and row
111           is specified on the command line, then the bounding box for that
112           cell is returned, where the top left cell is numbered from zero.
113           If both column and row arguments are specified, then the bounding
114           box spanning the rows and columns indicated is returned.
115
116       $master->gridColumnconfigure(index?, -option=>value, ...?)
117           Query or set the column properties of the index column of the
118           geometry master, $master.  The valid options are -minsize, -weight
119           and -pad.  If one or more options are provided, then index may be
120           given as a list of column indices to which the configuration
121           options will operate on.  The -minsize option sets the minimum
122           size, in screen units, that will be permitted for this column.  The
123           -weight option (an integer value) sets the relative weight for
124           apportioning any extra spaces among columns.  A weight of zero (0)
125           indicates the column will not deviate from its requested size.  A
126           column whose weight is two will grow at twice the rate as a column
127           of weight one when extra space is allocated to the layout.  The
128           -uniform option,  when  a non-empty  value  is  supplied,  places
129           the column in a uniform group with other columns that have the same
130           value for -uniform.  The  space for columns belonging to a uniform
131           group is allocated so that their sizes are always in  strict
132           proportion  to  their -weight values.   See  THE GRID ALGORITHM
133           below for further details.  The -pad option specifies the number of
134           screen units that will be added to the largest window contained
135           completely in that column when the grid geometry manager requests a
136           size from the containing window.  If only an option is specified,
137           with no value, the current value of that option is returned.  If
138           only the master window and index is specified, all the current
139           settings are returned in an list of "-option value" pairs.
140
141       $slave->gridConfigure(?$slave, ...?, options?)
142           The same as grid method.
143
144       $slave->gridForget?($slave, ...)?
145           Removes each of the $slaves from grid for its master and unmaps
146           their windows.  The slaves will no longer be managed by the grid
147           geometry manager.  The configuration options for that window are
148           forgotten, so that if the slave is managed once more by the grid
149           geometry manager, the initial default settings are used.
150
151       $slave->gridInfo
152           Returns a list whose elements are the current configuration state
153           of the slave given by $slave in the same option-value form that
154           might be specified to gridConfigure.  The first two elements of the
155           list are ``-in=>$master'' where $master is the slave's master.
156
157       $master->gridLocation(x, y)
158           Given  x and y values in screen units relative to the master
159           window, the column and row number at that x and y location is
160           returned.  For locations that are above or to the left of the grid,
161           -1 is returned.
162
163       $master->gridPropagate?(boolean)?
164           If boolean has a true boolean value such as 1 or on then
165           propagation is enabled for $master, which must be a window name
166           (see "GEOMETRY PROPAGATION" below).  If boolean has a false boolean
167           value then propagation is disabled for $master.  In either of these
168           cases an empty string is returned.  If boolean is omitted then the
169           method returns 0 or 1 to indicate whether propagation is currently
170           enabled for $master.  Propagation is enabled by default.
171
172       $master->gridRowconfigure(index?, -option=>value, ...?)
173           Query or set the row properties of the index row of the geometry
174           master, $master.  The valid options are -minsize, -weight and -pad.
175           If one or more options are provided, then index may be given as a
176           list of row indeces to which the configuration options will operate
177           on.  The -minsize option sets the minimum size, in screen units,
178           that will be permitted for this row.  The -weight option (an
179           integer value) sets the relative weight for apportioning any extra
180           spaces among rows.  A weight of zero (0) indicates the row will not
181           deviate from its requested size.  A row whose weight is two will
182           grow at twice the rate as a row of weight one when extra space is
183           allocated to the layout.  The -uniform  option, when a non-empty
184           value is supplied, places the row in a uniform group with other
185           rows that have the same  value for -uniform.   The space for rows
186           belonging to a uniform group is allocated so that their sizes are
187           always in strict proportion to  their -weight values.  See THE GRID
188           ALGORITHM below for further details.  The -pad option specifies the
189           number of screen units that will be added to the largest window
190           contained completely in that row when the grid geometry manager
191           requests a size from the containing window.  If only an option is
192           specified, with no value, the current value of that option is
193           returned.  If only the master window and index is specified, all
194           the current settings are returned in an list of "option-value"
195           pairs.
196
197       $slave->gridRemove?($slave, ...)?
198           Removes each of the $slaves from grid for its master and unmaps
199           their windows.  The slaves will no longer be managed by the grid
200           geometry manager.  However, the configuration options for that
201           window are remembered, so that if the slave is managed once more by
202           the grid geometry manager, the previous values are retained.
203
204       $master->gridSize
205           Returns the size of the grid (in columns then rows) for $master.
206           The size is determined either by the $slave occupying the largest
207           row or column, or the largest column or row with a -minsize,
208           -weight, or -pad that is non-zero.
209
210       $master->gridSlaves?(-option=>value)?
211           If no options are supplied, a list of all of the slaves in $master
212           are returned, most recently manages first.  -option can be either
213           -row or -column which causes only the slaves in the row (or column)
214           specified by value to be returned.
215

RELATIVE PLACEMENT

217       The grid method contains a limited set of capabilities that permit
218       layouts to be created without specifying the row and column information
219       for each slave.  This permits slaves to be rearranged, added, or
220       removed without the need to explicitly specify row and column
221       information.  When no column or row information is specified for a
222       $slave, default values are chosen for -column, -row, -columnspan and
223       -rowspan at the time the $slave is managed. The values are chosen based
224       upon the current layout of the grid, the position of the $slave
225       relative to other $slaves in the same grid method, and the presence of
226       the characters -, ^, and ^ in grid method where $slave names are
227       normally expected.
228
229       -   This increases the columnspan of the $slave to the left.  Several
230           -'s in a row will successively increase the columnspan. A - may not
231           follow a ^ or a x.
232
233       x   This leaves an empty column between the $slave on the left and the
234           $slave on the right.
235
236       ^   This extends the -rowspan of the $slave above the ^'s in the grid.
237           The number of ^'s in a row must match the number of columns spanned
238           by the $slave above it.
239

THE GRID ALGORITHM

241       The grid geometry manager lays out its slaves in three steps.  In the
242       first step, the minimum size needed to fit all of the slaves is
243       computed, then (if propagation is turned on), a request is made of the
244       master window to become that size.  In the second step, the requested
245       size is compared against the actual size of the master.  If the sizes
246       are different, then space is added to or taken away from the layout as
247       needed.  For the final step, each slave is positioned in its row(s) and
248       column(s) based on the setting of its sticky flag.
249
250       To compute the minimum size of a layout, the grid geometry manager
251       first looks at all slaves whose columnspan and rowspan values are one,
252       and computes the nominal size of each row or column to be either the
253       minsize for that row or column, or the sum of the padding plus the size
254       of the largest slave, whichever is greater.  Then the slaves whose
255       rowspans or columnspans are greater than one are examined.  If a group
256       of rows or columns need to be increased in size in order to accommodate
257       these slaves, then extra space is added to each row or column in the
258       group according to its weight.  For each group whose weights are all
259       zero, the additional space is apportioned equally.
260
261       When multiple rows or columns belong to a uniform group, the space
262       allocated to them is always in proportion to their weights. (A weight
263       of zero is considered to be 1.)  In other words, a row or column
264       configured with -weight 1 -uniform a will have exactly the same size as
265       any other row or column configured with -weight 1 -uniform a.  A row or
266       column configured with -weight 2 -uniform b will be exactly twice as
267       large as one that is configured with -weight 1 -uniform b.
268
269       More technically, each row or column in the group will have a size
270       equal to k*weight for some constant k.  The constant k is chosen so
271       that no row or column becomes smaller than its minimum size.  For
272       example, if all rows or columns in a group have the same weight, then
273       each row or column will have the same size as the largest row or column
274       in the group.
275
276       For masters whose size is larger than the requested layout, the
277       additional space is apportioned according to the row and column
278       weights.  If all of the weights are zero, the layout is centered within
279       its master.  For masters whose size is smaller than the requested
280       layout, space is taken away from columns and rows according to their
281       weights.  However, once a column or row shrinks to its minsize, its
282       weight is taken to be zero.  If more space needs to be removed from a
283       layout than would be permitted, as when all the rows or columns are at
284       there minimum sizes, the layout is clipped on the bottom and right.
285

GEOMETRY PROPAGATION

287       The grid geometry manager normally computes how large a master must be
288       to just exactly meet the needs of its slaves, and it sets the requested
289       width and height of the master to these dimensions.  This causes
290       geometry information to propagate up through a window hierarchy to a
291       top-level window so that the entire sub-tree sizes itself to fit the
292       needs of the leaf windows.  However, the gridPropagate method may be
293       used to turn off propagation for one or more masters.  If propagation
294       is disabled then grid will not set the requested width and height of
295       the master window.  This may be useful if, for example, you wish for a
296       master window to have a fixed size that you specify.
297

RESTRICTIONS ON MASTER WINDOWS

299       The master for each slave must either be the slave's parent (the
300       default) or a descendant of the slave's parent.  This restriction is
301       necessary to guarantee that the slave can be placed over any part of
302       its master that is visible without danger of the slave being clipped by
303       its parent.  In addition, all slaves in one call to grid must have the
304       same master.
305

STACKING ORDER

307       If the master for a slave is not its parent then you must make sure
308       that the slave is higher in the stacking order than the master.
309       Otherwise the master will obscure the slave and it will appear as if
310       the slave hasn't been managed correctly.  The easiest way to make sure
311       the slave is higher than the master is to create the master window
312       first:  the most recently created window will be highest in the
313       stacking order.
314

CREDITS

316       The grid method is based on ideas taken from the GridBag geometry
317       manager written by Doug. Stein, and the blt_table geometry manager,
318       written by George Howlett.
319

SEE ALSO

321       Tk::form Tk::pack Tk::place
322

KEYWORDS

324       geometry manager, location, grid, cell, propagation, size, pack,
325       master, slave
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329perl v5.32.0                      2020-07-28                           grid(3)
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