#  File src/library/graphics/R/filled.contour.R
#  Part of the R package, https://www.R-project.org
#
#  Copyright (C) 1995-2023 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/

filled.contour <-
function (x = seq(0, 1, length.out = nrow(z)),
          y = seq(0, 1, length.out = ncol(z)),
          z,
          xlim = range(x, finite=TRUE),
          ylim = range(y, finite=TRUE),
          zlim = range(z, finite=TRUE),
          levels = pretty(zlim, nlevels), nlevels = 20,
          color.palette = function(n) hcl.colors(n, "YlOrRd", rev = TRUE),
          col = color.palette(length(levels) - 1),
          plot.title, plot.axes, key.title, key.axes, key.border = NULL,
          asp = NA, xaxs = "i", yaxs = "i", las = 1, axes = TRUE,
          frame.plot = axes, ...)
{
    if (missing(z)) {
        if (!missing(x)) {
            if (is.list(x)) {
                z <- x$z
                y <- x$y
                x <- x$x
            }
            else {
                z <- x
                x <- seq.int(0, 1, length.out = nrow(z))
            }
        }
        else stop("no 'z' matrix specified")
    }
    else if (is.list(x)) {
        y <- x$y
        x <- x$x
    }
    if (any(diff(x) <= 0) || any(diff(y) <= 0))
        stop("increasing 'x' and 'y' values expected")

    mar.orig <- (par.orig <- par(c("mar","las","mfrow")))$mar
    on.exit(par(par.orig))

    w <- (3 + mar.orig[2L]) * par("csi") * 2.54
    layout(matrix(c(2, 1), ncol = 2L), widths = c(1, lcm(w)))
    par(las = las)

    ## Plot the 'plot key' (scale):
    mar <- mar.orig
    mar[4L] <- mar[2L]
    mar[2L] <- 1
    par(mar = mar)
    plot.new()
    plot.window(xlim = c(0,1), ylim = range(levels), xaxs = "i", yaxs = "i")
    rect(0, levels[-length(levels)], 1, levels[-1L], col = col, border = key.border)
    if (missing(key.axes)) {
        if (axes)
            axis(4)
    }
    else key.axes
    box()
    if (!missing(key.title))
	key.title

    ## Plot contour-image::
    mar <- mar.orig
    mar[4L] <- 1
    par(mar = mar)
    plot.new()
    plot.window(xlim, ylim, "", xaxs = xaxs, yaxs = yaxs, asp = asp)

    .filled.contour(x, y, z, levels, col)
    if (missing(plot.axes)) {
        if (axes) {
            title(main = "", xlab = "", ylab = "")
            Axis(x, side = 1)
            Axis(y, side = 2)
        }
    }
    else plot.axes
    if (frame.plot) box()
    if (missing(plot.title))
        title(...)
    else
	plot.title
    invisible()
}

.filled.contour <- function(x, y, z , levels, col)
{
    if (!is.matrix(z) || nrow(z) <= 1L || ncol(z) <= 1L)
        stop("no proper 'z' matrix specified")
    .External.graphics(C_filledcontour, x, y, z, levels, col)
    invisible()
}