[racket] slideshow, footer

On 2012-04-13 15:48:16 -0400, Geoffrey S. Knauth wrote:
> Is there a standard way that people use to add a footer and/or image to each slideshow slide?  I'm sure I can roll my own, but I was wondering if there were examples in the wild so I don't reinvent the wheel.
> 
> (I'm giving a CAP safety briefing tomorrow morning, and while I could do it in PowerPoint, which is what everyone does, the briefing involves looking at actual aviation maps and weather graphics real-time, which made me think of Racket Slideshow.)

I find that using Ryan's ppict/pslide library makes this kind of thing
easy to do. Here's an example:

  #lang racket
  
  (require slideshow
           slideshow/pict
           unstable/gui/pslide
           unstable/gui/ppict)
  
  (define (base-pict-with-footer)
    (ppict-do (blank client-w client-h)
              #:go (coord 0.5 0.95)
              (text "Footer text")))
  
  (parameterize ([pslide-base-pict base-pict-with-footer])
    (pslide (text "Body text")))

This adds a "Footer text" to each pslide by changing the base pict that
is used. The base pict sets down a footer near the bottom (just text in
this example, but you could make it anything you like).

Cheers,
Asumu