Add png_retina function, bump version

DESCRIPTION

@@ -1,8 +1,8 @@
 Package: envreportutils
 Type: Package
 Title: Utilities for common operations, mainly plotting
-Version: 0.4.1
-Date: 2017-01-19
+Version: 0.6.0
+Date: 2017-09-21
 Authors@R: c(person("Andy", "Teucher", role = c("aut", "cre"), email =
     "andy.teucher@gov.bc.ca"), 
     person("Stephanie", "Hazlitt", role = "aut", 

NAMESPACE

@@ -5,6 +5,7 @@ export(get_data_licence)
 export(get_data_license)
 export(multiplot)
 export(order_df)
+export(png_retina)
 export(theme_soe)
 export(theme_soe_facet)
 import(extrafont)

NEWS.md

@@ -1,3 +1,8 @@
+# envreportutils 0.6.0
+
+* Added function `png_retina()` - a drop in replacement for `png()` to produce 
+retina-quality graphics.
+
 # envreportutils 0.5.1
 
 * Two functions deprecated, functionality available in other CRAN packages.

R/png_retina.R

@@ -0,0 +1,37 @@
+#' Create png for retina display
+#' 
+#' This is a drop-in replacement for the \code{\link[grDevices]{png}} function 
+#' for creating images for the web for retina devices. Internally, it simply 
+#' doubles the width, height, and resolution specified. The intention is then
+#' that in the webpage that you would specify the \code{width} and \code{height} 
+#' attributes in the html at the original resolution.
+#'
+#' @inheritParams grDevices::png
+#'
+#' @return A plot device is opened: nothing is returned to the R interpreter.
+#' @export
+#' 
+#' @seealso \code{\link[grDevices]{png}}
+#'
+#' @examples
+#' 
+#' # You want to display at 500 * 500 in the web:
+#' png_retina("myplot.png", width = 500, height = 500)
+#' plot(x = 1:500, y = rnorm(500))
+#' dev.off()
+#' 
+#' # Although the output image will be 1000 * 1000, in the html you would put:
+#' # <img src="myplot.png", width="500", height="500" />
+#' 
+png_retina <- function(filename = "Rplot%03d.png", width = 480, height = 480, 
+                       units = "px", pointsize = 12, bg = "white",  res = NA, 
+                       ..., type = c("cairo", "cairo-png", "Xlib", "quartz"), 
+                       antialias) {
+  height <- height * 2
+  width <- width * 2
+  res <- ifelse(is.na(res), 144, res * 2)
+
+  grDevices::png(filename = filename, width = width, height = height, 
+                 units = units, pointsize = pointsize, bg = bg, res = res, ..., 
+                 type = type, antialias = antialias)
+}