Re: Top 10 IDL Requests

[Nick Bower <bowern(at)ses.curtin.edu.au>]

> \But your solution, like others, doesn't work "on (direct) graphics already
> rendered to the screen ", because the graphics already rendered to the
> screen are now just pixels. You can retrieve the pixels; you can (one way or

That is a simplistic solution to plotting.  In order to satisfy Paul's need
(something I definately would like to see too) graphics would be written to a
virtual metafile and not a standard pixmap.  So the sensible thing would be
that all plot commands drew vectors to the virtual metafile, and then the
viewport on each platform simply renders this as a pixmap, translating vector
to raster.

If it were done this way, you could implement highly functional zooming and
postscript dumps in the viewport which simply go back and access the vector
information in the virtual metafile.  I've seen matlab do it, and I'd say this
highlights the difference in the visualization approaches and considerations
the two packages have made.   It's clear to me which approach is a more
sophisticated.

nick