Possible more TODO features

[Daniel J S. <dan...@ie...>]

Here are a few other things that might be nice to have:

* Many times people want to plot a line representing some boundary or plane which basically means they'd like to have the line extend from one boundary of the plot to another.  In other words, they'd like an infinite length line that should be clipped at the boundary.  (Or a line that is infinite in one direction and not the other... a bit imprecised, math wise, but I think you get the idea.)  To do this now, I believe the user has to resort to computing the points of intersection of the line and the four possible boundaries.  (If they have a bit more knowledge about the slope of the line, guessing which boundaries intersect is easy.)  This isn't a difficult problem for the user, but it is a bit of a pain.  So, if the term->clip_region() function is implemented, it might be nice to have gnuplot do this work for the user.  So, for arrow, rather than just a "to"/"from", it might be nice to augment that with "thru"/"slope", or more generally w'x + b where w is a two dimensional 
or three dimensional vector perpendicular to the line or plane and b is a constant (commonly referred to as a hyperplane).  I'm not exactly sure what syntax one would use:

set arrow from 0,0 to border thru 1,1
set arrow from border to border thru 0,0 perp (1,1)

Requires some thought, but the idea of saving the user a bit of work seems worthwhile.


* How about a line format that puts a periodic arrowhead along its path?  Sort of this kind of thing:

----->----->----->----->----->----->----->----->----->----->

?  This sort of line is often useful for indicating flow or direction of travel.


Dan