gnuplot - why plotted lines disappear after certain zoom in level?

Question

I'm completely new to gnuplot. I'm trying to plot a couple of trivial series of data on one plot. Actually I mean a small number of simple segments [x1,y1] -> [x2,y2]

But I noticed an annoying behaviour: when I try to zoom my canvas with mouse into specified location, e.g. lines crossing point, my lines eventually disappear. Not all at once - they disappear one by one at different zoom levels. I'm not able to examine specific point from close up because of this. Is it possible prevent my graph elements from disappearing from window?

Answer 1

The behaviour of the plot when one or both end points of a line are outside the displayed range is controllable with set clip.

To have the line portion drawn which is inside the plot but both endpoints being outside, you must use set clip two.

Consider the following example:

plot '-' with linespoints
0.5 0.5
9.5 9.5
e

If you now zoom in, the line disappears. If you use set clip two before, then you can zoom in and the line is drawn:

set clip two
plot '-' with linespoints
0.5 0.5
9.5 9.5
e

(tested to work with 4.6.5)