R/autolayer.r

In affiner: A Finer Way to Render 3D Illustrated Objects in 'grid' Using Affine Transformations

utils::globalVariables(c("x", "y"))

autolayer.Coord1D <- function(x, ...) {
    ggplot2::geom_point(ggplot2::aes(x = x, y = y),
                        ..., 
                        data = data.frame(x = x$x, y = 0))
}

autolayer.Coord2D <- function(x, ...) {
    ggplot2::geom_point(ggplot2::aes(x = x, y = y),
                        ...,
                        data = as.data.frame(x))
}

autolayer.Point1D <- function(x, ...) {
    ggplot2::geom_vline(xintercept = -x$b / x$a)
}

autolayer.Line2D <- function(x, ...) {
    index_v <- which(x$b == 0)
    l <- list()
    if (length(index_v)) {
        l[[1L]] <- ggplot2::geom_vline(xintercept = -x$c / x$a, ...)
        x <- x[-index_v]
    }
    if (length(x)) {
        slope <- - x$a / x$b
        intercept <- - x$c / x$b
        l[[2L]] <- ggplot2::geom_abline(slope = slope, intercept = intercept, ...)
    }
    l
}