Application Frames

Reading

Frames

• are the central abstraction of an application
• are displayed as top-level window
• may also be displayed as regions embedded within other applications
• control the screen real estate managed by an application
• contain a hierarchy of panes -- from a library of standard panes, or custom defined panes
• are managed by special application called a frame manager
• keep track of Lisp state variables that contain the state of the application
• are used to access command-loop, gadgets, and look-and-feel-independence

Panes

• interactive objects
• analogous to the windows, gadgets, or widgets of other toolkits
• layout panes organize space
• extended stream panes present application-specific information
• gadget panes display data and obtain user input

Frame Managers

• control the realization of the look and feel of a frame
• interpret the specification of the application frame in the context of the available window system facilities
• take care of attaching the pane hierarchy of an application frame to an appropriate place in a window hierarchy

Kinds of Frame Managers

• desktop manager or window manager
  • allows a user to manipulate the frames of other applications
  • is usually a non-Lisp application
  • acts as a mediator between the Lisp application and the host desktop manager
  • application acting as frame managers
  • allow frames of other applications to be displayed within the host application

Constructing Application Frames

Before you can construct an actual instance of an application frame, you have to name it and define it by calling

define-application-frame (name superclasses slots &rest options)

This is a macro that helps you define a direct sub-class of the class standard-application-frame. The &rest options is where much of the action is because this is where one specifies command tables, panes for display, and the layout of the panes.

The following code makes and runs a minimal application frame:

(define-application-frame word		;name
    ()					;superclasses
  ()					;slots
  ;; options
  (:panes				;panes option
   (title				;pane name 
    :application)			;pane type
   (document				;pane name
    :application))			;pane type
  (:layouts				;layouts option
   (default				;layout name
       (vertically ()			;layout macros
	 (1/8 title)
	 (7/8 document)))))

(run-frame-top-level (make-application-frame 'word :height 300 :width 300))

Exercises

1. Load the CLIM package within your Lisp, and switch to the CLIM-USER package.
2. Define, make, and run a minimal CLIM application frame.
3. At the toplevel type

   (inspect (make-application-frame 'word :height 300 :width 300))

   Look for the panes and the command table.
4. Macro Expand your call to define-application-frame. Find the call to defclass.
5. Write a utility called make-and-run-frame that makes and runs an application frame.

Next: CLIM Panes