<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv=Content-Type content="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered medium)"> <style>  </style> </head> <body lang=EN-US link=blue vlink=purple> <div class=Section1> I am trying to understand the behavior of graphics output between (some of) the various run/display mechanisms available under PLT Scheme.  In particular, I want to understand the differences between running some code under DrScheme versus MrEd.  Another objective is to see if there is some way to get the behavior to be consistent across the two.  In each of them I am using the PLoT collection to generate an image-snip%.  [I have also included the files.]<o:p></o:p> <div style='mso-element:para-border-div;border:none;border-bottom:solid windowtext 1.0pt; padding:0in 0in 1.0pt 0in'> <o:p> </o:p> </div> <o:p> </o:p> test-1.ss<o:p></o:p> <o:p> </o:p> (require (lib "plot.ss" "plot"))<o:p></o:p> <o:p> </o:p> (printf "This is a plot of the sine function~n")<o:p></o:p> (plot (line sin))<o:p></o:p> <o:p> </o:p> When run under DrScheme, this prints the text and displays the plot.  Under MrEd (mred –r test-1.ss), the text is displayed, but the plot isn’t (not even textually).  I assume this is the difference between the behaviors of the respective REPLs.  [No biggie here, the IDE REPL behavior is richer than a pure run-time REPL.]<o:p></o:p> <o:p> </o:p> test-2.ss<o:p></o:p> <o:p> </o:p> (require (lib "plot.ss" "plot"))<o:p></o:p> <o:p> </o:p> (printf "This is a plot of the sine function~n")<o:p></o:p> (print (plot (line sin)))<o:p></o:p> (newline)<o:p></o:p> <o:p> </o:p> Under DrScheme, this has the same output as test-1.ss.  Under MrEd (mred –r test-2.ss, the text is displayed and the plot is displayed textually as #<struct:object:2d-view%>.  Based on an answer by Ryan Culpepper to a previous e-mail of mine, I assume this is due to the differences between the print routines in DrScheme and MrEd.<o:p></o:p> <o:p> </o:p> test-3.ss<o:p></o:p> <o:p> </o:p> (require (lib "plot.ss" "plot"))<o:p></o:p> <o:p> </o:p> (printf "This is a plot of the sine function~n")<o:p></o:p> (printf "~a~n" (plot (line sin)))<o:p></o:p> <o:p> </o:p> This has the same behavior as test-2.ss.  I just wanted to show that, under DrScheme, printf also displayed image-snip% instances.<o:p></o:p> <o:p> </o:p> test-4.ss<o:p></o:p> <o:p> </o:p> (require (lib "plot.ss" "plot"))<o:p></o:p> <o:p> </o:p> (define (test-4)<o:p></o:p>   (parameterize<o:p></o:p>       ((current-output-port<o:p></o:p>         (open-output-text-editor text)))<o:p></o:p>     (printf "This is a plot of the sine function~n")<o:p></o:p>     (print (plot (line sin)))<o:p></o:p>     (newline)))<o:p></o:p> <o:p> </o:p> (define frame<o:p></o:p>   (instantiate frame% ("Test 4")))<o:p></o:p> <o:p> </o:p> (define canvas (instantiate editor-canvas% (frame)<o:p></o:p>                  (min-width 500)<o:p></o:p>                  (min-height 450)<o:p></o:p>                  (style '(no-hscroll hide-vscroll))))<o:p></o:p> <o:p> </o:p> (define text (instantiate text% ()))<o:p></o:p> <o:p> </o:p> (send canvas set-editor text)<o:p></o:p> <o:p> </o:p> (send frame show #t)<o:p></o:p> <o:p> </o:p> (test-4)<o:p></o:p> <o:p> </o:p> This creates a separate window for the output.  The results in that window are the same as for test-2.ss – i.e. the plot is printed under DrScheme and just a textually representation under MrEd..  I had hoped that the open-output-text-editor produced a port with the same behavior across DrScheme and MrEd, but it doesn’t.  [This also seems to validate Ryan’s earlier comments on the behavior of the print, etc in DrScheme.]<o:p></o:p> <o:p> </o:p> test-5.ss<o:p></o:p> <o:p> </o:p> (require (lib "plot.ss" "plot"))<o:p></o:p> <o:p> </o:p> (define (test-5)<o:p></o:p>   (parameterize<o:p></o:p>       ((current-output-port<o:p></o:p>         (open-output-text-editor text)))<o:p></o:p>     (printf "This is a plot of the sine function~n")<o:p></o:p>     (printf "~a~n" (plot (line sin)))))<o:p></o:p> <o:p> </o:p> (define frame<o:p></o:p>   (instantiate frame% ("Test 4")))<o:p></o:p> <o:p> </o:p> (define canvas (instantiate editor-canvas% (frame)<o:p></o:p>                  (min-width 500)<o:p></o:p>                  (min-height 450)<o:p></o:p>                  (style '(no-hscroll hide-vscroll))))<o:p></o:p> <o:p> </o:p> (define text (instantiate text% ()))<o:p></o:p> <o:p> </o:p> (send canvas set-editor text)<o:p></o:p> <o:p> </o:p> (send frame show #t)<o:p></o:p> <o:p> </o:p> (test-5)<o:p></o:p> <o:p> </o:p> This one surprised me.  This is the same as test-4.ss, but uses printf instead of print to display the plot.  This displays the image-snip% textually under both DrScheme and MrEd.  [That’s why I included test-3.ss.]<o:p></o:p> <div style='mso-element:para-border-div;border:none;border-bottom:solid windowtext 1.0pt; padding:0in 0in 1.0pt 0in'> <o:p> </o:p> </div> <o:p> </o:p> It would be nice to have consistent graphical output in both graphical execution environments.  I think I understand what is going on ‘under the cover’ – at some level DrScheme and MrEd have different printing routines and DrScheme’s support write-special and MrEd’s don’t.  [Although test-5.ss still has me confused.]  Is it possible to get the DrScheme behavior in MrEd?  [For example, I had hoped that open-output-text-editor would do that for me.]<o:p></o:p> <o:p> </o:p> One other thing is the behavior under MzScheme.  It punts because of a dynamic require for #%mred-kernel failing – which I understand.  But, would it be possible to revert to the textual display of the objects in this case?<o:p></o:p> <o:p> </o:p> Sorry for the length of the post.<o:p></o:p> <o:p> </o:p> Doug<o:p></o:p> </div> </body> </html>