4.4. Packing Using Tables

Let's take a look at another way of packing - Tables. These can be extremely useful in certain situations.

Using tables, we create a grid that we can place widgets in. The widgets may take up as many spaces as we specify.

The first thing to look at, of course, is the gtk.Table() function:

  table = gtk.Table(rows=1, columns=1, homogeneous=False)

The first argument is the number of rows to make in the table, while the second, obviously, is the number of columns.

The homogeneous argument has to do with how the table's boxes are sized. If homogeneous is True, the table boxes are resized to the size of the largest widget in the table. If homogeneous is False, the size of a table boxes is dictated by the tallest widget in its same row, and the widest widget in its column.

The rows and columns are laid out from 0 to n, where n was the number specified in the call to gtk.Table(). So, if you specify rows = 2 and columns = 2, the layout would look something like this:

   0          1          2
  0+----------+----------+
   |          |          |
  1+----------+----------+
   |          |          |
  2+----------+----------+

Note that the coordinate system starts in the upper left hand corner. To place a widget into a box, use the following method:

  table.attach(child, left_attach, right_attach, top_attach, bottom_attach,
               xoptions=EXPAND|FILL, yoptions=EXPAND|FILL, xpadding=0, ypadding=0)

The table instance is the table you created with gtk.Table(). The first parameter ("child") is the widget you wish to place in the table.

The left_attach, right_attach, top_attach and bottom_attach arguments specify where to place the widget, and how many boxes to use. If you want a button in the lower right table entry of our 2x2 table, and want it to fill that entry ONLY, left_attach would be = 1, right_attach = 2, top_attach = 1, bottom_attach = 2.

Now, if you wanted a widget to take up the whole top row of our 2x2 table, you'd use left_attach = 0, right_attach = 2, top_attach = 0, bottom_attach = 1.

The xoptions and yoptions are used to specify packing options and may be bitwise OR'ed together to allow multiple options.

These options are:

FILLIf the table cell is larger than the widget, and FILL is specified, the widget will expand to use all the room available in the cell.
SHRINKIf the table widget was allocated less space then was requested (usually by the user resizing the window), then the widgets would normally just be pushed off the bottom of the window and disappear. If SHRINK is specified, the widgets will shrink with the table.
EXPANDThis will cause the table cell to expand to use up any remaining space allocated to the table.

Padding is just like in boxes, creating a clear area around the widget specified in pixels.

We also have set_row_spacing() and set_col_spacing() methods. These add spacing between the rows at the specified row or column.

  table.set_row_spacing(row, spacing)

and

  table.set_col_spacing(column, spacing)

Note that for columns, the space goes to the right of the column, and for rows, the space goes below the row.

You can also set a consistent spacing of all rows and/or columns with:

  table.set_row_spacings(spacing)

and,

  table.set_col_spacings(spacing)

Note that with these calls, the last row and last column do not get any spacing.