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?...
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 and arrangement of the table. The table queries the requested size of each widget. The requested size of a widget is the natural size of the widget (before the widget 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 normal size.
The total number of rows and columns in a table is determined from the indices specified. The table grows dynamically as windows are added at larger indices.
# 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 confines of the container.
You add widgets
to the table by row and column location. Row and column indices start from
zero.
# Add a label to the table
label .title -text "This is a title"
table . .title 0,0
The label .title is added to the table. We can add more widgets in the same
way.
# Add two buttons
button .ok -text "Ok"
button .cancel -text "Cancel"
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 centered horizontally along the
top of the table. We can make .title span two columns using the configure
operation.
# Make the label span both columns
table configure . .title -cspan 2
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.
# Create and pack the table
label .title -text "This is a title"
button .ok -text "Ok"
button .cancel -text "Cancel"
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).
# Each button will be as height of the 2nd row.
# Make the title label fill the entire top row
table configure . .title -cspan 2 -fill x
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.
The -padx and -pady options
control the amount of padding around the widget. Both options take a list
of one or two values.
# Pad each button 2 pixels on the left, and 4 on the right.
# Pad the title by two pixels above and below.
table configure . .title -pady 2
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 character-based widgets
(such as buttons, labels, text, listbox, 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 2nd row 1/2 inch high.
# Make the 1st column 2 inches wide
table configure . c0 -width 2.0i
table configure . r1 -height 0.5i
The new size for the row or column overrides its calculated 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 bottom 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 each column 4 pixels on the left, and 2 on the right.
# Pad above the title by two pixels
table configure . r0 -pady { 2 0 }
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 2nd column get bigger, not smaller
# Don't resize the first row
# Let the 1st column get smaller, but not bigger
table configure . c0 -resize shrink
table configure . c1 -resize expand
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.
# Don't let the scrollbars resize
# Create an empty space to balance the scrollbar
table . \
.title 0,0 -cspan 3 \
.canvas 1,1 -fill both \
.vscroll 1,2 -fill y \
.hscroll 2,1 -fill x
table configure . c2 r2 -resize none
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 column 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
It's not necessary to specify the container. The table command determines the container from the widget name.
The option and value pairs are specific to item. If option is specified with no value, then the command 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 specified). 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 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.
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 options are available for widgets:
- -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 specifies 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 considered.
- 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.
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 container 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.
- -width width
- Specifies the limits within that the width of the column may expand or shrink. Width is a list of bounding values. See the section BOUNDING for a description of this list. By default there are no constraints.
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 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.
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 partition 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 limits, but also specifies a nominal size nom. This overrides the calculated size of the window or partition.
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
Limitations
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 managers.
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.