list method for vapour xcontour

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: ximage
 Title: Draw Images of Raster Data and Related Adornments
-Version: 0.0.0.9005
+Version: 0.0.0.9006
 Authors@R: 
     person("Michael D.", "Sumner", , "[email protected]", role = c("aut", "cre"))
 Description: Draw images easily and as if doing that was considered desirable or  

NAMESPACE

@@ -1,5 +1,7 @@
 # Generated by roxygen2: do not edit by hand
 
+S3method(xcontour,default)
+S3method(xcontour,list)
 S3method(ximage,default)
 S3method(ximage,list)
 S3method(ximage,nativeRaster)

NEWS.md

@@ -1,7 +1,8 @@
 # ximage dev
 
-* `ximage()` can now plot sf::gdal_read objects. 
+* Added suport for `xcontour()` for the output output of `gdal_raster_data()` in {vapour}. 
 
+* `ximage()` can now plot sf::gdal_read objects. 
 
 * Fixed default extent for an array/matrix, it was transposed (!). 
 

R/xcontour.R

@@ -2,6 +2,8 @@
 #'
 #' To work with [ximage()]
 #'
+#' Input may be a matrix or a list from gdal_raster_data() in the vapour package.
+#'
 #' @param x something we can contour
 #' @inheritParams ximage
 #' @inheritDotParams ximage
@@ -16,6 +18,10 @@
 #' #ximage(im, add = TRUE, extent = ex)
 #' xcontour(v, add = TRUE, extent = ex, col = "white")
 xcontour <- function(x, extent = NULL, ..., add = FALSE) {
+  UseMethod("xcontour")
+}
+#' @export
+xcontour.default <- function(x, extent = NULL, ..., add = FALSE) {
   x <- t(x[nrow(x):1, ])
   if (is.null(extent)) extent <- c(0, ncol(x), 0, nrow(x))
   xre <- diff(extent[1:2])/nrow(x)
@@ -24,3 +30,49 @@ xcontour <- function(x, extent = NULL, ..., add = FALSE) {
   yy <- seq(extent[3] + yre/2, extent[4] - yre/2, length.out = ncol(x) )
   graphics::contour(xx, yy, x, add = add, ...)
 }
+#' @export
+xcontour.list <- function(x, extent = NULL, ..., add = FALSE) {
+
+  if (all(c("geotransform", "cols", "rows", "driver") %in% names(x))) {
+    ## smells like sf
+    stop("no xcontour for sf")
+    ximage_sf_data(x, extent = extent, zlim = zlim, add = add, ..., xlab = xlab, ylab = ylab, col = col)
+    return(invisible(x))
+  }
+   ## here validate that we have extent, dimension as attributes, otherwise just see if it's a matrix
+  attrs <- attributes(x)
+  if (!is.null(attrs$extent) && is.null(extent)) extent <- attrs$extent
+  dimension <- NULL
+  if (!is.null(attrs$dimension)) {
+    dimension <- attrs$dimension
+
+  }
+  projection <- NULL
+
+  if (is.null(dimension)) {
+    if (is.null(dim(x[[1]]))) {
+      dimension <- dim(x[[1]])
+    } else {
+    stop("no dimension known")
+    }
+  }
+ if (!is.null(attrs$projection)) projection <- attrs$projection
+  if (is.character(x[[1]])) {
+    if (grepl("^#", stats::na.omit(x[[1]])[1])) {
+      ## we have image data
+    } else {
+      ## can't read data in ximage
+      stop("can't read data in the this package")
+#      x[[1]] <- as.vector(t(elevation(source = x[[1]], extent = attr(x, "extent"), dimension = attr(x, "dimension"), projection = attr(x, "projection"))))
+    }
+  }
+
+
+    xcontour(matrix(x[[1]], dimension[2L], byrow = TRUE),
+                   extent = extent,  add = add, ...)
+
+  ##if (coastline) graphics::lines(coastline(extent, projection = projection, dimension = c(512, 512)))
+
+  ## return the materialized data
+  invisible(x)
+}