Re: maximing/resizing multiple x11: change of palette

[Dave D. <dde...@es...>]

Ethan Merritt <merritt@u.washington.edu> writes:

> On Monday 16 August 2004 01:50 am, Petr Mikulik <mi...@ph...> wrote:
>> There is a bug in the color palette treatment in the X11 terminal: when
>> using multiple X11 terminals, window redraw (requested e.g. by a window
>> manager) will change its palette.
>> 
>> Is it possible to fix it?
>
> I am not very familiar with this, and I may have it wrong.
> But It looks to me that the PM3D code would have to be re-written.
>
> As it is, gnuplot_x11 only maintains two GC (= "Graphics Context")
> structures. One of these is used for PM3D operations, and the other
> is used for everything else.   There is not currently any notion of
> keeping a separate GC for each plot window.  So if you redefine
> the PM3D GC to use a different palette, it affects all PM3D operations
> in all windows.
>
> I imagine it would be possible to create a new GC for each window,
> but I am not sure what pitfalls that would expose.
>


I had a quick look, and decided that the problem was that colors[] is
global, so that any change will affect all subsequent
repaints. Including the colors[] in the (gnuplot_x11) plot structure
may help.

I don't think the single GC is an issue - the values in the GC are
reset as required.


Eg in

/*-----------------------------------------------------------------------------
 *   display - display a stored plot
 *---------------------------------------------------------------------------*/

void
display(plot)
plot_struct *plot;
{

we have

...

    /* loop over accumulated commands from inboard driver */
    for (n = 0; n < plot->ncommands; n++) {

    ...

	/*   X11_linetype(type) - set line type  */
	else if (*buffer == 'L') {
	    sscanf(buffer, "L%4d", &lt);
	    lt = (lt % 8) + 2;
	    /* default width is 0 {which X treats as 1} */
	    width = widths[lt] ? user_width * widths[lt] : user_width;
	    if (dashes[lt][0]) {
		type = LineOnOffDash;
		XSetDashes(dpy, gc, 0, dashes[lt], strlen(dashes[lt]));
	    } else {
		type = LineSolid;
	    }
	    XSetForeground(dpy, gc, colors[lt + 3]);
	    XSetLineAttributes(dpy, gc, width, type, CapButt, JoinBevel);
	}


which is updating the Gc foreground colour, but from the global
colors[] array, which may have changed since the plot was created.

(I also decided that line widths and dashes could suffer from the same
 problem, but couldn't immediately reproduce any problem
)



dd
-- 
Dave Denholm              <dde...@es...>       http://www.esmertec.com