Re: Plotting contours together with 'with image' data

[sfeam <sf...@us...>]

On Saturday, 21 July 2018 16:49:32 sfeam via gnuplot-beta wrote:
> On Saturday, 21 July 2018 12:29:32 Dima Kogan wrote:

> > Yeah, this is an unfortunate consequence of the way we set up our
> > interface. Ideally, you'd specify the contour options per plot:
> > 
> >   splot A with lines contours, B with image contours, C with vectors
> >
> > Changing this retroactively is probably more trouble than it's worth.
> 
> Right.  The historical design for several of gnuplot's plotting modes
> was an all-or-nothing toggle.  "set hidden3d"  "set pm3d" "set contours".
> The code evolved to allow you to opt out of the global settings for
> individual plot components.  E.g.
> 
>    set hidden3d
>    splot FOO, BAZ with labels nohidden3d
> 
> guarantees that the labels in BAZ will not be obscured by the surface
> drawn for FOO.
> And for contours:
> 
>    set contour surface
>    splot  f(x,y),  g(x,y) nocontour, h(x,y) nosurface
> 
> produces a plot in which f() gets both surface and contours,
> g() gets surface only, and h() gets contours only.
> 
> pm3d evolved slightly differently. Instead of requiring a global
> setting and allowing plot components to opt out,  we now allow
> individual plot components to opt in by using the style "with pm3d".
> Yeah that's a bit inconsistent.  You might logically expect there to
> be a "nopm3d" option, but there isn't.

I am thinking that we could use the command

    set pm3d {explicit|implicit}

as a model for opt-in contours.  As it is now, "set contours" causes
all subsequent plots to use contours unless they cannot be contoured
or they opt out with "nocontour".  This is the equivalent of the 
state produced by "set pm3d implicit".   It might work to add a command
"set contours explicit" as we have for pm3d, meaning that subsequent
plots are only contoured if they use an explicit plot style "contours".

I don't think such a change would allow you to create any plot that you
cannot already create, but perhaps making "set pm3d" and "set contours"
more similar would be easier them both easier to understand.
What do you think?    

	Ethan