gnu: Add r-cairo.

* gnu/packages/statistics.scm (r-cairo): New variable.

gnu/packages/statistics.scm

@@ -5150,3 +5150,38 @@ (define-public r-tsne
     (description
      "This package provides a pure R implementation of the t-SNE algorithm.")
     (license license:gpl2+)))
+
+(define-public r-cairo
+  (package
+    (name "r-cairo")
+    (version "1.5-9")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "Cairo" version))
+       (sha256
+        (base32
+         "1x1q99r3r978rlkkm5gixkv03p0mcr6k7ydcqdmisrwnmrn7p1ia"))))
+    (properties `((upstream-name . "Cairo")))
+    (build-system r-build-system)
+    (inputs
+     `(("cairo" ,cairo)
+       ("libxt" ,libxt)))
+    (native-inputs
+     `(("pkg-config" ,pkg-config)))
+    (home-page "http://www.rforge.net/Cairo/")
+    (synopsis "R graphics device using Cairo graphics library")
+    (description
+     "This package provides a Cairo graphics device that can be use to
+create high-quality vector (PDF, PostScript and SVG) and bitmap
+output (PNG,JPEG,TIFF), and high-quality rendering in displays (X11
+and Win32).  Since it uses the same back-end for all output, copying
+across formats is WYSIWYG.  Files are created without the dependence
+on X11 or other external programs.  This device supports alpha
+channel (semi-transparent drawing) and resulting images can contain
+transparent and semi-transparent regions.  It is ideal for use in
+server environments (file output) and as a replacement for other
+devices that don't have Cairo's capabilities such as alpha support or
+anti-aliasing.  Backends are modular such that any subset of backends
+is supported.")
+    (license license:gpl2)))