X11_ymax_saved artifact in x11.trm... not

[Daniel J S. <dan...@ie...>]

At first I thought there was some kind of artifact in the x11.trm code 
regarding X11_ymax_saved, and the following related snippets:

     /* Dima Kogan Sep 2012: Above is true when generating the plot THE 
FIRST
        TIME.  I now save the sizing information every time the window sizes
        change (in the ..._saved variables). Thus I no longer need
        to ask for this information NOW, and can just use it.
      */

		if (X11_ymax_saved > 0.0) { /* use saved sizes if they're valid */
			term->h_char = X11_hchar_saved;
			term->v_char = X11_vchar_saved;
			term->h_tic = term->v_tic = X11_vchar_saved / 2.5;
			term->ymax = X11_ymax_saved;
		}

/* Cached sizing values for the x11 terminal.
  * Updated/Maintained in mouse.c
  */
int          X11_hchar_saved, X11_vchar_saved;
double       X11_ymax_saved = -1.0;

Nowhere in x11.trm is X11_ymax_saved set anywhere.  But then I saw in 
mouse.c the following:

	/* EAM FIXME:  Despite the name, only X11 uses this to pass font info.	*/
	/* Everyone else passes just the plot height and width.			*/
	if (!strcmp(term->name,"x11")) {
	    /* These are declared in ../term/x11.trm */
	    extern int          X11_hchar_saved, X11_vchar_saved;
	    extern double       X11_ymax_saved;

	    /* Cached...

This is a very good example of the code quality issues that Péter 
pointed out.  Here is a core-level file (mouse.c) that is going to a 
terminal file to modify some global variables via "extern".  These kinds 
of caching things should be kept local to the specific terminal.

[I wonder why

	    X11_ymax_saved = (double)term->xmax * (double)ge->my / 
fabs((double)ge->mx);

is being done in response to a GE_fontprops command.  Is GE_fontprops 
somehow guaranteed to happen if the user uses the mouse to resize the 
X11 window?  I then ask if caching the window size actually saves 
anything if this code in do_event() is being accessed more than 
X11_graphics() is, which in both cases might not be all that often.]

Furthermore, the mouse.c routine is do_event() which is what I called 
into question a little over a week ago.  Was it the Qt terminal that was 
calling this do_event routine directly in a recursive way?  And it 
seemed to me that Qt terminal didn't really need to do so because the 
information it was using was already available to the core code.

I don't think it is worth fixing right now, but grepping for "ifdef X11" 
shows up 20 times in a few core files.  It would be nice to disentangle 
that terminal from the main code.

Dan