Shorten line by delta on both sides

inner function to remove delta length from both sides of a line

remove_delta_off_line(line, delta)

Arguments

line	2 x 2 matrix of edge points of line
delta	numeric delta to be subtracted

Value

2 x 2 matrix of edges that are shrunk

Details

This function is shared with TCpredictionbands on github: TCpredictionbands.