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 how to create a new Gtk::Table:
Gtk::Table.new( rows, columns, homogeneous )
The first argument is the number of rows you want to make in the table, while the second is the number of columns. The homogeneous argument has to do with how the table's boxes are sized. If homogeneous is set to true, the table boxes will be resized to the size of the largest widget in the table. If homogeneous is set to false, the size of the table boxes is dictated by the tallest widget in it's same row, and the widest widget in its column.
The rows and columns are laid out from 0 to n, where n is was the numbers specified in the call to Gtk::Table.new. For example, 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:
Gtk::Table#attach( child, left_attach, right_attach, top_attach, bottom_attach, xoptions, yoptions, xpadding, ypadding)
The first argument ("child") is the widget you wish to place in the table.
The left and right 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 would 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:
Gtk::FILL
If the table is larger than the widget, and Gtk::FILL is specified, the widget will expand to use all the room available.
Gtk::SHRINK
If the table widget was allocated less space then was requested (usually be resizing the window), then the widgets would normally just be pushed off the bottom of the window and disappear. If Gtk::SHRINK is specified, the widgets will shrink with the table.
Gtk::EXPAND
This will cause the table to expand to use up any remaining space in the window.
Padding is just like in boxes, creating a clear area around the widget specified in pixels.
Gtk::Table#attach has a lot of options. So, there's a shortcut:
Gtk::Table#attach_defaults( child, left_attach, right_attach, top_attach, bottom_attach )
The X and Y options default to Gtk::FILL | Gtk::EXPAND, and X and Y padding are set to 0. The rest of the arguments are identical to the previous method.
We also have Gtk::Table#set_row_spacing and Gtk::Table#set_col_spacing. These methods place spacing between the rows at the specified row or column.
Gtk::Table#set_row_spacing( row, spacing )
and
Gtk::Table#set_column_spacing( column, spacing )
Please 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:
Gtk::Table#set_row_spacings( spacing )
and
Gtk::Table#set_col_spacings( spacing )
Note that with these calls, the last row and last column do not get any spacing.
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