#  File src/library/graphics/R/sunflowerplot.R
#  Part of the R package, http://www.R-project.org
#
#  Copyright (C) 1995-2013 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
#  http://www.r-project.org/Licenses/

sunflowerplot <- function(x, ...) UseMethod("sunflowerplot")

sunflowerplot.default <-
    function(x, y = NULL, number, log = "", digits = 6L,
             xlab = NULL, ylab = NULL, xlim = NULL, ylim = NULL,
             add = FALSE, rotate = FALSE,
             pch = 16, cex = 0.8, cex.fact =  1.5, col = par("col"), bg = NA,
             size = 1/8, seg.col = 2, seg.lwd = 1.5, ...)
{
    ## Argument "checking" as plot.default:

    xlabel <- if (!missing(x)) deparse(substitute(x))
    ylabel <- if (!missing(y)) deparse(substitute(y))
    is.xyn <- (is.list(x) && all(c("x","y","number") %in% names(x)))
                                        # as, e.g., from grDevices::xyTable(.)
    xy <-
        if(is.xyn) {
            number <- x$number
            x
        } else xy.coords(x, y, xlabel, ylabel, log)
    if(!add) {
        xlab <- if (is.null(xlab)) xy$xlab else xlab
        ylab <- if (is.null(ylab)) xy$ylab else ylab
        xlim <- if (is.null(xlim)) range(xy$x[is.finite(xy$x)]) else xlim
        ylim <- if (is.null(ylim)) range(xy$y[is.finite(xy$y)]) else ylim
    }
    n <- length(xy$x)
    if(missing(number)) {
	tt <- xyTable(xy, digits = digits)## in ../../grDevices/R/calc.R
	x <- tt$x
	y <- tt$y
	number <- tt$number
    } else {
        if(length(number) != n)
            stop("'number' must have same length as 'x' and 'y'")
        np <- number > 0
        x <- xy$x[np]
        y <- xy$y[np]
        number <- number[np]
    }
    n <- length(x)
    dev.hold(); on.exit(dev.flush())
    if(!add)
        plot(x, y, xlab = xlab, ylab = ylab,
             xlim = xlim, ylim = ylim, log = log, type = "n", ...)

    n.is1 <- number == 1
    if(any(n.is1))
        points(x[ n.is1], y[ n.is1], pch = pch, col = col, bg = bg, cex = cex)
    if(any(!n.is1)) {
        points(x[!n.is1], y[!n.is1], pch = pch, col = col, bg = bg, cex = cex/cex.fact)
        i.multi <- (1L:n)[number > 1]
        ppin <- par("pin")
        pusr <- par("usr")
        xr <- size * abs(pusr[2L] - pusr[1L])/ppin[1L]
        yr <- size * abs(pusr[4L] - pusr[3L])/ppin[2L]

        i.rep <- rep.int(i.multi, number[number > 1])
        z <- numeric()
        for(i in i.multi)
            z <- c(z, 1L:number[i] + if(rotate) stats::runif(1) else 0)
        deg <- (2 * pi * z)/number[i.rep]
        segments(x[i.rep], y[i.rep],
                 x[i.rep] + xr * sin(deg),
                 y[i.rep] + yr * cos(deg),
                 col=seg.col, lwd = seg.lwd)
    }
    invisible(list(x=x, y=y, number=number))
}

sunflowerplot.formula <-
    function(formula, data = NULL, xlab = NULL, ylab = NULL, ...,
             subset, na.action = NULL)
{
    if(missing(formula) || (length(formula) != 3L))
	stop("formula missing or incorrect")
    m <- match.call(expand.dots = FALSE)
    if(is.matrix(eval(m$data, parent.frame())))
	m$data <- as.data.frame(data)
    m$xlab <- m$ylab <- m$... <- NULL
    m$na.action <- na.action # force use of default for this method
    require(stats, quietly = TRUE)
    m[[1L]] <- quote(stats::model.frame)
    mf <- eval(m, parent.frame())
    if(NCOL(mf) != 2L)
        stop("'formula' should specify exactly two variables")
    if(is.null(xlab)) xlab <- names(mf)[2L]
    if(is.null(ylab)) ylab <- names(mf)[1L]
    sunflowerplot(mf[[2L]], mf[[1L]], xlab = xlab, ylab = ylab, ...)
}