R/plot_grid.R

In trinker/embodied: Tools for working with embodied actions (movements within space).

#' Title
#' 
#' Description
#' 
#' @param file The imput png file.
#' @param text.color The color to make the coordinate labels.
#' @param text.size The size of the coordinate labels.
#' @param grid.color The color to make the grid.
#' @param grid.size The thickness of the grid lines.
#' @param grid.data The output from the \code{grid_calc} function.
#' @return Returns an image with a grid and labels.
#' @references
#' \url{http://stackoverflow.com/a/21043587/1000343}
#' @author Troy (\url{stackoverflow.com}) and Tyler Rinker <tyler.rinker@@gmail.com>.
#' @export
#' @importFrom ggplot2 ggplot annotation_custom geom_text geom_segment coord_cartesian aes theme_bw
#' @importFrom png readPNG
#' @importFrom grid rasterGrob
#' @examples
#' \dontrun{
#' deb <- system.file("extdata/deb_roy.png", package = "embodied")
#' plot_grid(deb, grid.data = grid_calc(5))
#' }
plot_grid <- function(file, text.color = "gray60", text.size = 2, 
    grid.color = text.color, grid.size = .25, grid.data = grid_calc()){
	
    ## Address `no visible binding for global variable`
    x <- y <- labs <- xend <- yend <- NULL
	
    width <- grid.data[["columns"]]
    height<- grid.data[["rows"]]
    ggplot(grid.data[["points"]]) + theme_bw()+
        annotation_custom(rasterGrob(readPNG(file), 0, 0, 1, 1, 
        	just=c("left", "bottom")), 0, width, 0, height)+
        geom_text(aes(x=x, y=y, label=labs), color=text.color, 
        	size = text.size)+
        geom_segment(aes(x=x, xend=xend, y=y, yend=yend), 
        	data=grid.data[["coords"]], color=grid.color,
            size = grid.size) +
        coord_cartesian(c(0, width), c(0, height))
}