Add full support for ragg (#4388)

DESCRIPTION

@@ -42,6 +42,7 @@ Imports:
     withr (>= 2.0.0)
 Suggests:
     covr,
+    ragg,
     dplyr,
     ggplot2movies,
     hexbin,

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* `ggsave()` now uses ragg to render raster output if ragg is available 
+  (@thomasp85, #4388)
+
 * `coord_sf()` now has an argument `default_crs` that specifies the coordinate
   reference system (CRS) for non-sf layers and scale/coord limits. This argument
   defaults to the World Geodetic System 1984 (WGS84), which means x and y positions

R/save.r

@@ -31,7 +31,7 @@
 #'   are combined to create the fully qualified file name. Defaults to the
 #'   working directory.
 #' @param scale Multiplicative scaling factor.
-#' @param width,height,units Plot size in `units` ("in", "cm", or "mm").
+#' @param width,height,units Plot size in `units` ("in", "cm", "mm", or "px").
 #'   If not supplied, uses the size of current graphics device.
 #' @param dpi Plot resolution. Also accepts a string input: "retina" (320),
 #'   "print" (300), or "screen" (72). Applies only to raster output types.
@@ -75,13 +75,13 @@
 #' }
 ggsave <- function(filename, plot = last_plot(),
                    device = NULL, path = NULL, scale = 1,
-                   width = NA, height = NA, units = c("in", "cm", "mm"),
+                   width = NA, height = NA, units = c("in", "cm", "mm", "px"),
                    dpi = 300, limitsize = TRUE, bg = NULL, ...) {
 
   dpi <- parse_dpi(dpi)
   dev <- plot_dev(device, filename, dpi = dpi)
   dim <- plot_dim(c(width, height), scale = scale, units = units,
-    limitsize = limitsize)
+    limitsize = limitsize, dpi = dpi)
 
   if (!is.null(path)) {
     filename <- file.path(path, filename)
@@ -122,12 +122,12 @@ parse_dpi <- function(dpi) {
   }
 }
 
-plot_dim <- function(dim = c(NA, NA), scale = 1, units = c("in", "cm", "mm"),
-                     limitsize = TRUE) {
+plot_dim <- function(dim = c(NA, NA), scale = 1, units = c("in", "cm", "mm", "px"),
+                     limitsize = TRUE, dpi = 300) {
 
   units <- match.arg(units)
-  to_inches <- function(x) x / c(`in` = 1, cm = 2.54, mm = 2.54 * 10)[units]
-  from_inches <- function(x) x * c(`in` = 1, cm = 2.54, mm = 2.54 * 10)[units]
+  to_inches <- function(x) x / c(`in` = 1, cm = 2.54, mm = 2.54 * 10, px = dpi)[units]
+  from_inches <- function(x) x * c(`in` = 1, cm = 2.54, mm = 2.54 * 10, px = dpi)[units]
 
   dim <- to_inches(dim) * scale
 
@@ -158,18 +158,34 @@ plot_dev <- function(device, filename = NULL, dpi = 300) {
   force(dpi)
 
   if (is.function(device)) {
-    if ("file" %in% names(formals(device))) {
-      dev <- function(filename, ...) device(file = filename, ...)
-      return(dev)
-    } else {
-      return(device)
+    args <- formals(device)
+    call_args <- list()
+    if ("file" %in% names(args)) {
+      call_args$file <- filename
+    }
+    if ("res" %in% names(args)) {
+      call_args$res <- dpi
+    }
+    if ("units" %in% names(args)) {
+      call_args$units <- 'in'
     }
+    dev <- function(...) do.call(device, modify_list(list(...), call_args))
+    return(dev)
   }
 
   eps <- function(filename, ...) {
     grDevices::postscript(file = filename, ..., onefile = FALSE, horizontal = FALSE,
       paper = "special")
   }
+  if (requireNamespace('ragg', quietly = TRUE)) {
+    png_dev <- ragg::agg_png
+    jpeg_dev <- ragg::agg_jpeg
+    tiff_dev <- ragg::agg_tiff
+  } else {
+    png_dev <- grDevices::png
+    jpeg_dev <- grDevices::jpeg
+    tiff_dev <- grDevices::tiff
+  }
   devices <- list(
     eps =  eps,
     ps =   eps,
@@ -178,11 +194,11 @@ plot_dev <- function(device, filename = NULL, dpi = 300) {
     svg =  function(filename, ...) svglite::svglite(file = filename, ...),
     emf =  function(...) grDevices::win.metafile(...),
     wmf =  function(...) grDevices::win.metafile(...),
-    png =  function(...) grDevices::png(..., res = dpi, units = "in"),
-    jpg =  function(...) grDevices::jpeg(..., res = dpi, units = "in"),
-    jpeg = function(...) grDevices::jpeg(..., res = dpi, units = "in"),
+    png =  function(...) png_dev(..., res = dpi, units = "in"),
+    jpg =  function(...) jpeg_dev(..., res = dpi, units = "in"),
+    jpeg = function(...) jpeg_dev(..., res = dpi, units = "in"),
     bmp =  function(...) grDevices::bmp(..., res = dpi, units = "in"),
-    tiff = function(...) grDevices::tiff(..., res = dpi, units = "in")
+    tiff = function(...) tiff_dev(..., res = dpi, units = "in")
   )
 
   if (is.null(device)) {

tests/testthat/test-ggsave.R

@@ -85,23 +85,19 @@ test_that("scale multiplies height & width", {
 
 # plot_dev ---------------------------------------------------------------------
 
-test_that("function is passed back unchanged", {
-  expect_equal(plot_dev(png), png)
-})
-
 test_that("unknown device triggers error", {
   expect_error(plot_dev("xyz"), "Unknown graphics device")
   expect_error(plot_dev(NULL, "test.xyz"), "Unknown graphics device")
 })
 
 
 test_that("text converted to function", {
-  expect_identical(body(plot_dev("png"))[[1]], quote(grDevices::png))
+  expect_identical(body(plot_dev("png"))[[1]], quote(png_dev))
   expect_identical(body(plot_dev("pdf"))[[1]], quote(grDevices::pdf))
 })
 
 test_that("if device is NULL, guess from extension", {
-  expect_identical(body(plot_dev(NULL, "test.png"))[[1]], quote(grDevices::png))
+  expect_identical(body(plot_dev(NULL, "test.png"))[[1]], quote(png_dev))
 })
 
 # parse_dpi ---------------------------------------------------------------