[Plplot-devel] plenv() issues

[<jc...@fe...>]

Hi,

I have a recurrent problem with plenv() that I would like to discuss.

For start, plenv() is so handy that I always use it whenever possible.

But with multiplots (sub-windows or whatever -- set with plssub()), I=20
always have a problem: plenv() always advance the page, which is not=20
desirable. For interactive languages, one might wish to keep making=20
plots in the same sub-window until satisfied, and then advance to the=20
next or any other sub-window. This is not possible to do with plenv(),=20
as it always advance the page, which in multi-plot mode means another=20
sub-window.

A possible cure would be to do a pladv(desired_page -1) followed by =20
plenv(), but this fails if one desires to plot in sub-window 1, as=20
pladv(0) has a different behavior, issuing a pleop/plbop sequence.

So I always end up having a private copy of plenv() with the following=20
modifications:

 if ( plsc->nsubx * plsc->nsuby !=3D 1) {
    /* multiplot, erase current subwindow, plclear() does not work!*/
    /* don't advance page! */
    plvpor(0,1,0,1)
    plwind(0,1,0,1)
    plcol(0);plpsty(0)
    plfill(4, x_rect, y_rect); /* fill sub-window with background color=20
*/
   }
  else
    pladv(0)
 =20
CVS committing something like this would break code compatibility, as=20
users that depend on plenv() in multiplot mode would need to issue a=20
pladv(0) before.

What do you think of this problem? Is there a "cure" that does not=20
influence other users?

Thanks,
Joao