src/library/graphics/R/arrows.R

#  File src/library/graphics/R/arrows.R
#  Part of the R package, https://www.R-project.org
#
#  Copyright (C) 1995-2014 The R Core Team
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  A copy of the GNU General Public License is available at
#  https://www.R-project.org/Licenses/

arrows <-
    function(x0, y0, x1 = x0, y1 = y0, length = 0.25, angle = 30, code = 2,
             col = par("fg"), lty = par("lty"), lwd = par("lwd"), ...)
{
    if (missing(x1) && missing(y1))
        stop("one of 'x1' and 'y1' must be given")
    if (length(length) > 1 || length(angle) > 1 || length(code) > 1)
        warning("'length', 'angle', or 'code' greater than length 1; values after the first are ignored")
    .External.graphics(C_arrows, x0, y0, x1, y1, length = length,
                       angle = angle, code = code, col = col,
                       lty = lty, lwd = lwd, ...)
    invisible()
}