Re: Again: canvas size

[Ethan M. <merritt@u.washington.edu>]

On Friday 14 October 2005 01:37 am, Aapo Lankinen wrote:
> On Thu, 2005-10-13 at 09:18 -0700, Ethan Merritt wrote:
> > Let me phrase that in a different way:
> > 
> > I strongly advocate that "set size" have the same behaviour
> > regardless of whether it is called before or after "set term".
> > It should affect the scaling of the next plot to be drawn,
> > but it should never affect the size of the canvas[*].
> 
> Does that mean there should be a new command "set canvas" or a dedicated
> "canvas" option that all terminals should implement?

Maybe.

There are at least three classes of terminals:
- pixel terminals (png pbm x11 win ...)
- scalable vector devices (post latex svg emf cgm mif fig ...)
- fixed-size hardware (pen_plotters ...)

Harald Harders and I have been discussing the possibility of
allowing sizes to be specified in physical units (cm mm in).
The scalable vector devices could handle this easily.
Pixel device would need to be assigned a pixels-per-unit
scale factor, which imply a new terminal option along the
lines of "dpi <foo>".  The fixed-size devices probably have
some intrinsic and unchangeable scale, but gnuplot probably
cannot determine what that is on its own.

We had not progressed to the point of discussing what sort of
error message or default  behaviour would be appropriate if, e.g.,
the user requests a  size in cm but the current output device
has no idea what is a "cm".

But even if we never implement such a sweeping global
change, it is clear that many people would like a
size option for the PostScript and TeX based terminals.


-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195