R Under development (unstable) (2025-07-22 r88445 ucrt) -- "Unsuffered Consequences"
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> library(grid)
> library(gridSVG)

Attaching package: 'gridSVG'

The following objects are masked from 'package:grid':

    linearGradient, pattern, radialGradient

The following object is masked from 'package:grDevices':

    dev.off

> 
> pdf(file = NULL)
> grid.newpage()
> # We are just going to be drawing a cross for our pattern
> crossGrob <- gTree(children = gList(
+     linesGrob(),
+     linesGrob(x = unit(0:1, "npc"), y = unit(1:0, "npc"),
+               gp = gpar(lwd = 1))
+ ))
> 
> # Call the pattern "cross"
> # Using a small device size because the line widths
> # will be too small otherwise
> registerPatternFill("cross", grob = crossGrob,
+                     dev.width = 1, dev.height = 1)
> 
> grid.circle(name = "filledcircle")
> # Applying the pattern semi-transparently to the circle
> grid.patternFill("filledcircle", label = "cross", alpha = 0.5)
> grid.export("pattern-test.svg")
> dev.off()
null device 
          1 
> 
> # Now lets create a new pattern that uses the existing pattern
> # but much larger
> pdf(file = NULL)
> grid.newpage()
> registerPatternFillRef("bigcross", "cross",
+                        width = 0.3, height = 0.3)
> grid.circle(name = "filledcircle")
> grid.patternFill("filledcircle", label = "bigcross", alpha = 0.5)
> grid.export("pattern-test-ref.svg")
> dev.off()
null device 
          1 
> 
> # Test pattern offset
> pdf(file = NULL)
> grid.newpage()
> grid.rect(y=1, height=.5, just="top", name="zero-offset")
> grid.patternFill("zero-offset", label="cross")
> offsetPattern <- pattern(crossGrob, x=unit(1, "cm"),
+                          dev.width=1, dev.height=1)
> grid.rect(y=0, height=.5, just="bottom", name="non-zero-offset")
> grid.patternFill("non-zero-offset", offsetPattern)
> grid.export("pattern-test-offset.svg")
> dev.off()
null device 
          1 
> 
> 
> proc.time()
   user  system elapsed 
   0.81    0.12    0.92