Re: unified dashes

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

On Wednesday 17 June 2009, Petr Mikulik wrote:
> > > It seems x11 supports the "dash" option, but ignores this.
> > > Is the dash line functionality not implemented?
> > 
> > It is implemented and fully functional.
> > It just happens to look terrible on the screen, so the default
> > settings don't use it :-)
> > 
> > The definition of dash types is controlled by Xresources.
> > See the file Gnuplot.app-defaults for full information.
> 
> In my $HOME/.Xdefaults, I have no dash option (compared to 
> Gnuplot.app-defaults). Therefore I expect that running
> 
> 	gnuplot -dashed
> 
> would use the default dashed pattern sequence, it does not seem so.
> 
> It works after
> 	xrdb -merge Gnuplot.app-defaults 
> 	gnuplot -dashed
> 
> Could these defaults work also without putting the new stuff into xrdb?

You don't like configuration files?

> > > Could wxt add also this option?

Added to CVS a few days ago.

> Comparing the dashed output of x11, wxt, postscript, pdfcairo and pngcairo 
> for "dashcolor.dem", the pattern is not consistent -- dash length are 
> different, in some terminals there is "-." and in some "-..". It would be 
> great if the sequence is consistent, for example:
> 
> - (solid), -- (dashed), .. (dotted?), -. (dashdot), --. (dashdashdot),
> -.. (dashdotdot) etc.
> 
> I propose that the dash stuff to be removed from config's (of x11, for 
> example) and replace it by user-defined values?
> 
> plot sin(x) with line dashtype "-.." {dl NNN | dd NNN}

There have been past discussions about this.
I think the best approach suggested so far is to add "dashtype" as a
property in struct lp_style_type, and track it as a regular line 
property along with line width, line color, point type, point style, and so on.

> I'm not sure how "dashlength|dl" works ... maybe "dashdensity|dd" option 
> could be used to increase/decrese dash density?

Most terminals specify dash pattern by an array of lengths; successive
array elements control the length of the first line segment, the length of
the first gap, the length of the second line segment, the length of the
second gap, and so on.  "dashlength" is applied as a multiplier for these
lengths.