5.1 Organizing panes in columns and rows

You will frequently need to organize a number of different elements in rows and columns. The column-layout and row-layout elements are provided to make this easy.

The following is a simple example showing the use of column-layout .

(contain (make-instance 'column-layout

         :description (list

                      (make-instance 'text-input-pane)

                      (make-instance 'list-panel

                              :items '(1 2 3 4 5)))))

Figure 5.1 An example of using column-layout

1. Define the following elements:

(setq button1 (make-instance 'push-button

                             :data "Button 1"

                             :callback 'test-callback))

(setq button2 (make-instance 'push-button

                             :data "Button 2"

                             :callback 'test-callback))

(setq editor (make-instance 'editor-pane))

(setq message (make-instance 'display-pane

                             :text "A display pane"))

(setq text (make-instance 'text-input-pane

                          :title "Text: "

                          :title-position :left

                          :callback 'test-callback))

These will be used in the examples throughout the rest of this chapter.

To arrange any number of elements in a column, create a layout using column-layout , listing the elements you wish to use. For instance, to display title , followed by text and button1 , type the following into a Listener:

(contain (make-instance 'column-layout

                        :description

                          (list text button1)))

Figure 5.2 A number of elements displayed in a column

To arrange the same elements in a row, simply replace column-layout in the example above with row-layout . If you run this example, close the column layout window first: each CAPI element can only be on the screen once at any time.

Layouts can be given horizontal and vertical scroll bars, if desired; the keywords :horizontal-scroll and :vertical-scroll can be set to t or nil , as necessary.

When creating panes which can be resized (for instance, list panels, editor panes and so on) you can specify the size of each pane relative to the others by listing the proportions of each. This can be done via either the :y-ratios keyword (for column layouts) or the :x-ratios keyword (for row layouts).

 (contain (make-instance 'column-layout

           :description (list

                        (make-instance 'display-pane)

                        (make-instance 'editor-pane)

                        (make-instance 'listener-pane))

           :y-ratios '(1 5 3)))

You may need to resize this window in order to see the size of each pane.

Note that the heights of the three panes are in the proportions specified. The :x-ratios keyword will adjust the width of panes in a row layout in a similar way.