Re: Argh: Why are arrows clipped to the graph?

[Harald H. <h.h...@tu...>]

On Fri, 11 Nov 2005, Daniel J Sebald wrote:

> > What is the exact reason that prevents fixing post.trm (and maybe other
> > broken terminals) so that it would correctly update term->xmax and
> > term->ymax?  I would imagine that it wouldn't be terribly difficult to
> > change accordingly the values of these two variables when the postscript
> > internal canvas grow.  Is it somehow a problem with backward
> > compatibility?
>
> I don't see why things have to be done this way.  Does "canvas" have the
> same meaning as "view port".

Yes.

> The thing is, in PostScript I don't think
> one has to worry at all about plotting beyond the "view port".  (Sorry,
> P.S. terminology isn't fresh in my mind right now.)  It automatically
> takes care of that, doesn't it?  Why impose some inferior clipping
> method?

No, not really automatically. But it is fairly easy to define a clipping
path inside the produced Postscript file. Thus, only for Postscript we
would not have this problem. But the problem also applies for other
terminals. Try

set size 2,2
set terminal png
set output 'asdf.png'
plot sin(x)
set output

Have of the tic marks are missing.

> Instead, in the case of P.S., interpret term->xmax and term->ymax as
> simply boundaries of where the plot is viewed.  Or, if those aren't the
> appropriate variables, conceptually I hope you understand my point.

The point is that term->xmax and term->ymax denote the position where the
screen coordinate system has the values 1,1. They do not denote the upper
right corner of the canvas (view port or BoundingBox).

> Also, write a nicer do_arrow(), as Ethan suggests.  I think I could do
> it fairly easily, but I simply don't have time now.  It would have to
> wait until after the holidays.

What do you want to improve? For me, the Postscript arrows are good
enough.

> [...]  Believe it or not,
> PostScript can have a viewing angle for rectangular images.  I think for
> now, the generic pixel (parallelogram) by pixel (parallelogram) method
> will have to do.

Yes, of course. Postscript can do nearly everything except translucent
objects. For me, it would be much more interesting to enable gnuplot to
read in common picture files as jpg or png.

Best regards
Harald

-- 
Harald Harders
h.h...@tu...
http://www.harald-harders.de