5 Laying Out CAPI Panes

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 ofcolumn-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 usingcolumn-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 usingcolumn-layout, listing the elements you wish to use. For instance, to displaytitle, followed bytext andbutton1, 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 replacecolumn-layout in the example above with row-layout. If you run this example, note that the elements in the original column layout disappear as soon as the row layout is created: each CAPI element can only be on the screen once at any time. Putting it into a new layout will remove it from its previous parent.

Layouts can be given horizontal and vertical scroll bars, if desired; the keywords:horizontal-scroll and:vertical-scroll can be set tot ornil, 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.

CAPI User Guide, Liquid Common Lisp Version 5.0 - 2 OCT 1997

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