The R Project SVN – R – Diff – /trunk/src/library/grid/tests/paths.R

         y <- y + unit(rev(seq(n)) - mean(seq(n)), "lines")
+    }
     grid.text(lines, y=y, gp=gpar(fontfamily="HersheySans"))
+}
+devMask <- function(aMask, lMask) {
+    support <- dev.capabilities()$masks
+    if (is.character(support)) {
+        if ("alpha" %in% support) {
+            aMask
+        } else {
+            if ("luminance" %in% support) {
+                as.mask(lMask, type="luminance")
+            } else {
+                FALSE
+            }
+        }
+    } else {
+        FALSE
+    }
+}
 ################################################################################
 ## Paths that produce same result as normal drawing
 grid.newpage()
 grid.stroke(circleGrob())
 clipped by circle path
 result is two half-moons", .8)
 ## path that is masked
 grid.newpage()
-pushViewport(viewport(mask=circleGrob(r=.2, gp=gpar(fill="black"))))
+pushViewport(viewport(mask=devMask(circleGrob(r=.2, gp=gpar(fill="black")),
+                                   circleGrob(r=.2, gp=gpar(col="white",
+                                                            fill="white")))))
 grid.fill(circleGrob(1:2/3, r=.1), gp=gpar(fill="grey"))
 popViewport()
 HersheyLabel("filled path (two circles)
 masked by filled circle
 result is two half-moons", .8)

The R Project SVN R