CLIM question: modifying Highlighting

[<@IU.AI.SRI.COM:slug-admin@iu.ai.sri.com>]

    Date: Mon, 20 Jul 1992 14:52 EDT
    From: jclose@chesapeake.ads.com (Jeff Close)

    I apologize in advance if this is inappropriate for this list (I'm not
    sure if we try to cover CLIM or not).  

Sure, why not.  Although there is a CLIM-specific list: CLIM@BBN.com.

    I want to modify the highlighting of a presentation in CLIM.  If I
    knew the methods used I could put an :around or :after on the right
    method.  Any ideas about this or any other approach?  Thanks much for
    any help.

Use the CLIM defining macro DEFINE-PRESENTATION-METHOD to define a
HIGHLIGHT-PRESENTATION method on your presentation type.  This will
replace the default method; it is not an :around or :after method.

Here is an example of making the ticks of a ruler highlight with their
number.

;;; -*- Mode: LISP; Syntax: Common-Lisp; Base: 10; Package: CLIM-USER -*-

(define-presentation-type tick ())

(define-presentation-method highlight-presentation ((type tick) record stream state)
  state
  (multiple-value-bind (left top right) (clim:bounding-rectangle* record)
    (let ((sn (princ-to-string (presentation-object record))))
      (draw-string* stream sn
		    (round (+ left right) 2) (+ top -1)
		    :align-x :center :align-y :bottom :ink +flipping-ink+))))


(defun ruler-test (&key (tick-width 20) (margin 40) (n-ticks 10) (stream *standard-output*))
  (let ((y+ 100) (y- 85)
	(xl margin) (xr (+ margin (* n-ticks tick-width)))
	(tw/2 (round tick-width 2)))
    (draw-line* stream xl y+ xr y+)
    (loop for i from 0 to n-ticks
	  for x = (+ (* i tick-width) xl)
	  for x- = (- x tw/2) for x+ = (+ x tw/2) do
      (with-output-as-presentation (:stream stream
				    :object i
				    :type 'tick)
	(draw-rectangle* stream x- y- x+ y+ :ink +white+)
	(draw-line* stream x y+ x y-))))
  (accept 'tick :stream stream :prompt nil))