add instruction for saving pict to a file to Misc docs

[spdegabrielle]

It is one of those questions that comes up periodically and I'll do this soon

[bennn]

What is the best way to save a pict to a file?

I normally use pict->bitmap and save the bitmap to a png file source:

(define (save-pict fn p [kind 'png])
  (define bm (pict->bitmap p))
  (send bm save-file fn 'png))

But the quality isn't good enough to use in a paper. Scribble does a better job when it converts picts to pdfs in a document.

[camoy]

For picts in papers I use this code to generate encapsulated PostScript files (modified from metapict):

(define (save-pict-eps path pict)
  (define ps-setup (new ps-setup%))
  (send ps-setup copy-from (current-ps-setup))
  (send ps-setup set-file path)
  (send ps-setup set-margin 0 0)
  (send ps-setup set-scaling 1 1)
  (send ps-setup set-translation 0 0)
  (send ps-setup set-editor-margin 0 0)
  (define dc
    (parameterize ([current-ps-setup ps-setup])
      (new post-script-dc%
           [width (pict-width pict)]
           [height (pict-height pict)]
           [interactive #f]
           [parent #f]
           [use-paper-bbox #f]
           [as-eps #t]
           [output path])))
  (send dc set-smoothing 'smoothed)
  (send dc start-doc "")
  (send dc start-page)
  (draw-pict pict dc 0 0)
  (send dc end-page)
  (send dc end-doc))

Some journals (including JFP) request illustrations in EPS instead of PDF.

EDIT: Update with Robby's suggestion.

[rfindler]

Nice! (Probably a good idea to make a new ps-setup object (copying it from current-ps-setup and using parameterize to install it) if this gets turned into a library.)