Re: cross, x and star points

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

On Saturday, 17 May 2014 11:38:52 PM Jonathan Thornburg wrote:
> On Sat, May 17, 2014 at 12:22:51PM +0200, Karl-Friedrich Ratzsch wrote:
> > Pointtype 3 in most terminals (emf being the notable exception)
> > is just a superposition of pt 1+2, so it completely hides them if
> > put at the same position. I've looked at an old plot of mine,
> > and thought "i know these points should be at the same position,
> > but are two of them even there?"
> 
> A related problem: if we define coordinates so that pointtype 1
> (+ sign) has line segments running from (-1,0) to (+1,0) and
> (0,-1) to (0,+1), then pointtype 2 (x sign) has line segments
> running from (-1,-1) to (+1,+1) and (-1,+1) to (+1,-1).  In other
> words, the line segments for pointtype 2 are sqrt(2) times as long
> as the arms for pointtype 1, so pointtype 2 looks sqrt(2) times bigger.
> 
> The result is that if I want to use both point-type 1 and 2 and have
> the symbols look the same size arms (==> line segments the same length)
> then I need to specify
>   plot ... with points pointtype 1 pointsize 1.000, \
>        ... with points pointtype 2 pointtype 0.707
> 
> This makes gnuplot scripts a bit less readable.
> 
> Unfortunately it's hard to fix this in a backwards-compatible way.
> I suppose we could introduce new point types (maybe use negative
> numbers??) scaled so that the maximum radius of any ink from the
> point center is always the same.  Or add a new 'set' option to toggle
> the current vs a sqrt(2)-times-smaller definition of the "x" points
> (types 2 and 3).
> 
> Neither of these reqlly qualifies as an *elegant* solution.  Does
> anyone have better ideas?

You have many options for handling point symbols now.

All of the original symbols drawn with simple vectors
look crude compared to using proper symbol glyphs.

Have a look at 
   http://gnuplot.sourceforge.net/demo_cvs/lines_arrows.html 

		Ethan