change plotted segment ends from round to flat

Question

When i use segments() to draw a segment using R, the ends always appear rounded. How can I change the ends to flat?

Answer 1

From ?par:

 ‘lend’ The line end style.  This can be specified as an integer or
      string:

      ‘0’ and ‘"round"’ mean rounded line caps [_default_];

      ‘1’ and ‘"butt"’ mean butt line caps;

      ‘2’ and ‘"square"’ mean square line caps.

For example:

plot(0:1,0:1,type="n")
par(lend=0); segments(0,0.2,1,0.2,lwd=8)
par(lend=1); segments(0,0.4,1,0.4,lwd=8)
par(lend=2); segments(0,0.6,1,0.6,lwd=8)

or segments(0,0.2,1,0.2,lwd=8, lend=1) etc.

(You have to look pretty carefully to see the difference, especially between "butt" and "square" caps)