Mastering Perl/Tk

The form Geometry Manager

The final geometry manager we want to cover is form. Recently added into the Perl/Tk distribution, form is a very different geometry manager than those we’ve seen so far. To try and compare it with what we already know, it behaves like a combination of pack and place. Using form, it is legal to overlap widgets (as you would with place), but you can also display the widgets relative to each other and stretch them out to fill the entire available area and resize with the window (as you would with pack). The combination of all these abilities results in a powerful geometry manager.

When using form, each edge of a widget can be attached to something: the container’s grid, another widget, or nothing at all. You can also use springs to push your widgets around in the window based on the strength (or weight) of the spring. As with the other geometry managers, you can add padding to your widget.

Let’s look at the options briefly, then go into more detail on how to use them.

Options for form

The following are all the legal options for form. The following sections show you how to use these options to the best effect.

-bottom => attachment

Uses the given attachment on the bottom side of the widget.

-bottomspring => weight

Uses the given weight for a spring on the bottom side of the widget.

-fill => 'x' | 'y' | 'both' | 'none'

Specifies the direction in which to fill when springs are used. There is no default value.

-in => $master

Uses $master as the container ...