NAME
table - Arranges widgets in a table
SYNOPSIS
table container ?widget index option value?...
table arrange container
table cget container ?item? option
table configure container ?item?... ?option value?...
table extents container item
table forget widget ?widget?...
table info container item
table locate container x y
table containers ?switch? ?arg?
table save container
table search container ?switch arg?...
_________________________________________________________________
DESCRIPTION
The table command arranges widgets in a table. The align
ment of widgets is detemined by their row and column posi
tions and the number of rows or columns that they span.
INTRODUCTION
Probably the most painstaking aspect of building a graphi
cal application is getting the placement and size of the
widgets just right. It usually takes many iterations to
align widgets and adjust their spacing. That's because
managing the geometry of widgets is simply not a packing
problem, but also graphical design problem. Attributes
such as alignment, symmetry, and balance are more impor
tant than minimizing the amount of space used for packing.
The table geometry manager arranges widgets in a table.
It's easy to align widgets (horizontally and vertically)
or to create empty space to balance the arrangement of the
widgets. Widgets (called slaves in the Tk parlance) are
arranged inside a containing widget (called the master).
Widgets are positioned at row,column locations and may
span any number of rows or columns. More than one widget
can occupy a single location.
The placement of widget windows determines both the size
requested size of each widget. The requested size of a
widget is the natural size of the widget (before the wid
get is shrunk or expanded). The height of each row and
the width of each column is the largest widget spanning
that row or column. The size of the table is in turn the
sum of the row and column sizes. This is the table's nor
mal size.
The total number of rows and columns in a table is deter
mined from the indices specified. The table grows dynami
cally as windows are added at larger indices.
EXAMPLE
The table geometry manager is created by invoking the
table command.
# Create a table in the root window
table .
The window . is now the container of the table. Widgets
are packed into the table and displayed within the con
fines of the container.
You add widgets to the table by row and column location.
Row and column indices start from zero.
label .title -text "This is a title"
# Add a label to the table
table . .title 0,0
The label .title is added to the table. We can add more
widgets in the same way.
button .ok -text "Ok"
button .cancel -text "Cancel"
# Add two buttons
table . .ok 1,0
table . .cancel 1,1
Two buttons .ok and .cancel are now packed into the second
row of the table. They each occupy one cell of the table.
By default, widgets span only a single row and column.
The first column contains two widgets, .title and .ok. By
default, the widest of the two widgets will define the
width of the column. However, we want .title to be cen
tered horizontally along the top of the table. We can
make .title span two columns using the configure opera
tion.
# Make the label span both columns
The label .title will now be centered along the top row of
the table.
In the above example, we've create and arranged the layout
for the table invoking the table command several times.
Alternately, we could have used a single table command.
label .title -text "This is a title"
button .ok -text "Ok"
button .cancel -text "Cancel"
# Create and pack the table
table . \
.title 0,0 -cspan 2 \
.ok 1,0 \
.cancel 1,1
The table will override the requested width and height of
the container so that the window fits the table exactly.
This also means that any change to the size of table will
be propagated up through the Tk window hierarchy. This
feature can be turned off using the configure operation
again.
table configure . -propagate no
You can also set the width of height of the table to a
specific value. This supersedes the calculated table size.
# Make the container 4 inches wide, 3 inches high
table configure . -reqwidth 4i -reqheight 3i
If a widget is smaller than the cell(s) it occupies, the
widget will float within the extra space. By default, the
widget will be centered within the space, but you can
anchor the widget to any side of cell using the -anchor
configuration option.
table configure . .ok -anchor w
The -fill option expands the widget to fill the extra
space either vertically or horizontally (or both).
# Make the title label fill the entire top row
table configure . .title -cspan 2 -fill x
# Each button will be as height of the 2nd row.
table configure . .ok .cancel -fill y
The width of .title will be the combined widths of both
columns. Both .ok and .cancel will become as tall as the
second row.
around the widget. Both options take a list of one or two
values.
# Pad the title by two pixels above and below.
table configure . .title -pady 2
# Pad each button 2 pixels on the left, and 4 on the right.
table configure . .ok .cancel -padx { 2 4 }
If the list has only one value, then both exterior sides
(top and bottom or left and right) of the widget are
padded by that amount. If the list has two elements, the
first specifies padding for the top or left side and the
second for the bottom or right side.
Like the container, you can also override the requested
widths and heights of widgets using the -reqwidth and
-reqheight options. This is especially useful with char
acter-based widgets (such as buttons, labels, text, list
box, etc) that let you specify their size only in units of
characters and lines, instead of pixels.
# Make all buttons one inch wide
table configure . .ok .cancel -reqwidth 1i
Each row and column of the table can be configured, again
using the configure operation. Rows are and columns are
designated by Ri and Ci respectively, where i is the index
of the row or column.
For example, you can set the size of a row or column.
# Make the 1st column 2 inches wide
table configure . c0 -width 2.0i
# Make the 2nd row 1/2 inch high.
table configure . r1 -height 0.5i
The new size for the row or column overrides its calcu
lated size. If no widgets span the row or column, its
height or width is zero. So you can use the -width and
-height options to create empty spaces in the table.
# Create an empty row and column
table configure . r2 c2 -width 1i
The -pady option lets you add padding to the top and bot
tom sides of rows. The -padx option adds padding to the
left and right sides of columns. Both options take a list
of one or two values.
# Pad above the title by two pixels
# Pad each column 4 pixels on the left, and 2 on the right.
table configure . c* -padx { 2 4 }
Notice that you can configure all the rows and columns
using either R* or C*.
When the container is resized, the rows and columns of the
table are also resized. Only the rows or columns that
contain widgets (a widget spans the row or column) grow or
shrink. The -resize option indicates whether the row or
column can be shrunk or stretched. If the value is
shrink, the row or column can only be resized smaller. If
expand, it can only be resized larger. If none, the row
or column is frozen at its requested size.
# Let the 1st column get smaller, but not bigger
table configure . c0 -resize shrink
# Let the 2nd column get bigger, not smaller
table configure . c1 -resize expand
# Don't resize the first row
table configure . r0 -resize none
The following example packs a canvas, two scrollbars, and
a title. The rows and columns containing the scrollbars
are frozen at their requested size, so that even if the
frame is resized, the scrollbars will remain the same
width.
table . \
.title 0,0 -cspan 3 \
.canvas 1,1 -fill both \
.vscroll 1,2 -fill y \
.hscroll 2,1 -fill x
# Don't let the scrollbars resize
table configure . c2 r2 -resize none
# Create an empty space to balance the scrollbar
table configure . c0 -width .vscroll
Note that the value of the -width option is the name of a
widget window. This indicates that the width of the col
umn should be the same as the requested width of .vscroll.
Finally, the forget operation removes widgets from the
table.
# Remove the windows from the table
table forget .quit .frame
command determines the container from the widget name.
OPERATIONS
The following operations are available for the table:
table container ?widget index option value?...
Adds the widget widget to the table at index.
Index is a row,column position in the table. It
must be in the form row,column where row and column
are the respective row and column numbers, starting
from zero (0,0 is the upper leftmost position).
Row and column may also be numeric expressions that
are recursively evaluated. If a table doesn't
exist for container, one is created. Widget is the
path name of the window, that must already exist,
to be arranged inside of container. Option and
value are described in the WIDGET OPTIONS section.
table arrange container
Forces the table to compute its layout immediately.
Normally, the table geometry manager will wait
until the next idle point, before calculating the
size of its rows and columns. This is useful for
collecting the normal sizes of rows and columns,
that are based upon the requested widget sizes.
table cget container ?item? option
Returns the current value of the configuration
option specific to item given by option. Item is
either a row or column index, or the path name of a
widget. Item can be in any form describe in the
configure operation below. If no item argument is
provided, then the configuration option is for the
table itself. Option may be any one of the options
described in the appropiate section for item.
table configure container item... ?option value?...
Queries or modifies the configuration options spe
cific to item. If no option is specified, this
command returns a list describing all of the avail
able options for item If the argument item is omit
ted, then the specified configuration options are
for the table itself. Otherwise item must be
either a row or column specification, or the path
name of a widget. The following item types are
available.
Ci Specifies the column of container to be con
figured. Item must be in the form Cn, where
i is the index of the column. See the COL
UMN OPTIONS section.
Ri Specifies the row of container to be
where i is the index of the row. See the
ROW OPTIONS section.
widget Specifies a widget of container to be
queried. Widget is the path name of a wid
get packed in container. See the WIDGET
OPTIONS section.
No argument
Specifies that the table itself is to be
queried. See the TABLE OPTIONS section for
a description of the option-value pairs for
the table.
The option and value pairs are specific to item.
If option is specified with no value, then the com
mand returns a list describing the one named option
(this list will be identical to the corresponding
sublist of the value returned if no option is spec
ified). If one or more option-value pairs are
specified, then the command modifies the given
option(s) to have the given value(s); in this case
the command returns the empty string.
table extents container index
Queries the location and dimensions of row and
columns in the table. Index can be either a row or
column index or a table index. Returns a list of
the x,y coordinates (upperleft corner) and dimen
sions (width and height) of the cell, row, or col
umn.
table forget widget ?widget?...
Requests that widget no longer have its geometry
managed. Widget is the pathname of the window cur
rently managed by some table. The window will be
unmapped so that it no longer appears on the
screen. If widget is not currently managed by any
table, an error message is returned, otherwise the
empty string.
table info container item
Returns a list of the current configuration options
for item. The list returned is exactly in the form
that might be specified to the table command. It
can be used to save and reset table configurations.
Item must be one of the following.
Ci Specifies the column of container to be
queried. Item must be in the form Cn,
where n is the index of the column.
Ri Specifies the row of container to be
i is the index of the row.
widget Specifies a widget of container to be
queried. Widget is the path name of a wid
get packed in container.
No argument
Specifies that the table itself is to be
queried.
table locate container x y
Returns the table index (row,column) of the cell
containing the given screen coordinates. The x and
y arguments represent the x and y coordinates of
the sample point to be tested.
table containers ?switch arg?
Returns a list of all container windows matching a
given criteria (using switch and arg). If no
switch and arg arguments are given, the names of
all container windows (only those using the table
command) are returned. The following are valid
switches:
-pattern pattern
Returns a list of pathnames of all container
windows matching pattern.
-slave window
Returns the name of the container window of
table managing window. Window must be the
path name of widget. If window is not man
aged by any table, the empty string is
returned.
table search container ?switch arg?...
Returns the names of all the widgets in container
matching the criteria given by switch and arg.
Container is name of the container window associ
ated with the table to be searched. The name of
the widget is returned if any one switch-arg crite
ria matches. If no switch-arg arguments are given,
the names of all widgets managed by container are
returned. The following are switches are avail
able:
-pattern pattern
Returns the names of any names of the wid
gets matching pattern.
-span index
Returns the names of widgets that span
index. A widget does not need to start at
form row,column, where row and column are
valid row and column numbers.
-start index
Returns the names of widgets that start at
index. Index must be in the form row,col
umn, where row and column are valid row and
column numbers.
TABLE OPTIONS
To configure the table itself, you omit the item argument
when invoking the configure operation.
table configure container ?option value?...
The following options are available for the table:
-padx pad
Sets how much padding to add to the left and
right exteriors of the table. Pad can be a
list of one or two numbers. If pad has two
elements, the left side of the table is
padded by the first value and the right side
by the second value. If pad has just one
value, both the left and right sides are
padded evenly by the value. The default is
0.
-pady pad
Sets how much padding to add to the top and
bottom exteriors of the table. Pad can be a
list of one or two numbers. If pad has two
elements, the area above the table is padded
by the first value and the area below by the
second value. If pad is just one number,
both the top and bottom areas are padded by
the value. The default is 0.
-propagate boolean
Indicates if the table should override the
requested width and height of the container
window. If boolean is false, container will
not be resized. Container will be its
requested size. The default is 1.
WIDGET OPTIONS
widgets are configured by specifying the name of the wid
get when invoking the configure operation.
table configure container widget ?option value?...
Widget must be the path name of a window already packed in
the table associated with container. The following
-anchor anchor
Anchors widget to a particular edge of the
cell(s) it resides. This option has effect
only if the space of the spans surrounding
widget is larger than widget. Anchor speci
fies how widget will be positioned in the
space. For example, if anchor is center
then the window is centered in the rows and
columns it spans; if anchor is w then the
window will be aligned with the leftmost
edge of the span. The default is center.
-columnspan number
Sets the number of columns widget will span.
The default is 1.
-columncontrol control
Specifies how the width of widget should
control the width of the columns it spans.
Control is either normal, none, or full.
The default is normal.
none The width of widget is not consid
ered.
full Only the width of widget will be
considered when computing the
widths of the columns.
normal Indicates that the widest widget
spanning the column will determine
the width of the span.
-fill fill
Specifies if widget should be stretched to
fill any free space in the span surrounding
widget. Fill is either none, x, y, both.
The default is none.
x The widget can grow horizontally.
y The widget can grow vertically.
both The widget can grow both verti
cally and horizontally.
none The widget does not grow along
with the span.
-ipadx pixels
Sets how much horizontal padding to add
internally on the left and right sides of
tance like 2 or 0.3i. The default is 0.
-ipady pixels
Sets how much vertical padding to add inter
nally on the top and bottom of widget. Pix
els must be a valid screen distance like 2
or 0.3i. The default is 0.
-padx pad
Sets how much padding to add to the left and
right exteriors of widget. Pad can be a
list of one or two numbers. If pad has two
elements, the left side of widget is padded
by the first value and the right side by the
second value. If pad has just one value,
both the left and right sides are padded
evenly by the value. The default is 0.
-pady pad
Sets how much padding to add to the top and
bottom exteriors of widget. Pad can be a
list of one or two numbers. If pad has two
elements, the area above widget is padded by
the first value and the area below by the
second value. If pad is just one number,
both the top and bottom areas are padded by
the value. The default is 0.
-reqheight height
Specifies the limits of the requested height
for widget. Height is a list of bounding
values. See the BOUNDING SIZES section for
a description of this list. By default, the
height of widget is its requested height
with its internal padding (see the -ipady
option). The bounds specified by height
either override the height completely, or
bound the height between two sizes. The
default is "".
-reqwidth width
Specifies the limits of the requested width
for widget. Width is a list of bounding
values. See the BOUNDING SIZES section for
a description of this list. By default, the
width of widget is its requested width with
its internal padding (set the -ipadx
option). The bounds specified by width
either override the width completely, or
bound the height between two sizes. The
default is "".
Sets the number of rows widget will span.
The default is 1.
-rowcontrol control
Specifies how the height of widget should
control the height of the rows it spans.
Control is either normal, none, or full.
The default is normal.
none The height of widget is not con
sidered.
full Only the height of widget will be
considered when computing the
heights of the rows.
normal Indicates that the tallest widget
spanning the row will determine
the height of the span.
COLUMN OPTIONS
To configure a column in the table, specify the column
index as Ci, where i is the index of the column to be con
figured.
table configure container Ci ?option value?...
If the index is specified as C*, then all columns of the
table will be configured. The following options are
available for table columns.
-padx pad
Sets the padding to the left and right of
the column. Pad can be a list of one or two
numbers. If pad has two elements, the left
side of the column is padded by the first
value and the right side by the second
value. If pad has just one value, both the
left and right sides are padded evenly by
the value. The default is 0.
-resize mode
Indicates that the column can expand or
shrink from its requested width when the
table is resized. Mode must be one of the
following: none, expand, shrink, or both.
If mode is expand the width of the column is
expanded if there is extra space in the con
tainer window. If mode is shrink its width
may be reduced beyond its requested width if
there is not enough space in the container.
The default is none.
Specifies the limits within that the width
of the column may expand or shrink. Width
is a list of bounding values. See the sec
tion BOUNDING SIZES for a description of
this list. By default there are no con
straints.
ROW OPTIONS
To configure a row in the table, specify the row index as
Ri, where i is the index of the row to be configured.
table configure container Ri ?option value?...
If the index is specified as R*, then all rows of the
table will be configured. The following options are
available for table rows.
-height height
Specifies the limits of the height that the
row may expand or shrink to. Height is a
list of bounding values. See the section
BOUNDING SIZES for a description of this
list. By default there are no constraints.
-pady pad
Sets the padding above and below the row.
Pad can be a list of one or two numbers. If
pad has two elements, the area above the row
is padded by the first value and the area
below by the second value. If pad is just
one number, both the top and bottom areas
are padded by the value. The default is 0.
-resize mode
Indicates that the row can expand or shrink
from its requested height when the table is
resized. Mode must be one of the following:
none, expand, shrink, or both. If mode is
expand the height of the row is expanded if
there is extra space in the container. If
mode is shrink its height may be reduced
beyond its requested height if there is not
enough space in the container. The default
is none.
BOUNDING SIZES
Sometimes it's more useful to limit resizes to an accept
able range, than to fix the size to a particular value or
disallow resizing altogether. Similar to the way the wm
command lets you specify a minsize and maxsize for a
toplevel window, you can bound the sizes the container, a
widget, row, or column may take. The -width, -height,
-reqwidth, and -reqheight options, take a list of one,
instead preventing resizing, bound the size of the scroll
bars between two values.
table . \
.title 0,0 -cspan 3 \
.canvas 1,1 -fill both \
.vscroll 1,2 -fill y \
.hscroll 2,1 -fill x
# Bound the scrollbars between 1/8 and 1/2 inch
table configure . c2 -width { 0.125 0.5 }
table configure . r2 -height { 0.125 0.5 }
table configure . vscroll .hscroll -fill both
The scrollbars will get no smaller than 1/8 of an inch, or
bigger than 1/2 inch. The initial size will be their
requested size, so long as it is within the specified
bounds.
How the elements of the list are interpreted is dependent
upon the number of elements in the list.
{} Empty list. No bounds are set. The
default sizing is performed.
{ x } Fixes the size to x. The window or par
tition cannot grow or shrink.
{ min max }
Sets up minimum and maximum limits for
the size of the window or partition. The
window or partition can be reduced less
than min, nor can it be stretched beyond
max.
{ min max nom }
Specifies minimum and maximum size lim
its, but also specifies a nominal size
nom. This overrides the calculated size
of the window or partition.
MISCELLANEOUS
Another feature is that you can put two widgets in the
same cell of the table. This is useful when you want to
add decorations around a widget.
frame .frame -bd 1 -relief sunken
button .quit -text "Quit"
# Put both the frame and the button in the same cell.
table . \
.quit 1,0 -padx 2 -pady 2 \
.frame 1,0 -fill both
A long standing bug in Tk (circa 1993), there is no way to
detect if a window is already a container of a different
geometry manager. This is usually done by accident, such
as the following where all three widgets are arranged in
the same container ".", but using different geometry man
agers.
table .f1
...
pack .f2
...
grid .f3
This leads to bizarre window resizing, as each geometry
manager applies its own brand of layout policies. When
the container is a top level window (such as "."), your
window manager may become locked as it responds to the
never-ending stream of resize requests.
KEYWORDS
frame, geometry manager, location, table, size
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