```
# NOT RUN {
pathSample <- function(x, y, rule, gp = gpar()) {
if (is.na(rule))
grid.path(x, y, id = rep(1:2, each = 4), gp = gp)
else
grid.path(x, y, id = rep(1:2, each = 4), rule = rule, gp = gp)
if (!is.na(rule))
grid.text(paste("Rule:", rule), y = 0, just = "bottom")
}
pathTriplet <- function(x, y, title) {
pushViewport(viewport(height = 0.9, layout = grid.layout(1, 3),
gp = gpar(cex = .7)))
grid.rect(y = 1, height = unit(1, "char"), just = "top",
gp = gpar(col = NA, fill = "grey"))
grid.text(title, y = 1, just = "top")
pushViewport(viewport(layout.pos.col = 1))
pathSample(x, y, rule = "winding",
gp = gpar(fill = "grey"))
popViewport()
pushViewport(viewport(layout.pos.col = 2))
pathSample(x, y, rule = "evenodd",
gp = gpar(fill = "grey"))
popViewport()
pushViewport(viewport(layout.pos.col = 3))
pathSample(x, y, rule = NA)
popViewport()
popViewport()
}
pathTest <- function() {
grid.newpage()
pushViewport(viewport(layout = grid.layout(5, 1)))
pushViewport(viewport(layout.pos.row = 1))
pathTriplet(c(.1, .1, .9, .9, .2, .2, .8, .8),
c(.1, .9, .9, .1, .2, .8, .8, .2),
"Nested rectangles, both clockwise")
popViewport()
pushViewport(viewport(layout.pos.row = 2))
pathTriplet(c(.1, .1, .9, .9, .2, .8, .8, .2),
c(.1, .9, .9, .1, .2, .2, .8, .8),
"Nested rectangles, outer clockwise, inner anti-clockwise")
popViewport()
pushViewport(viewport(layout.pos.row = 3))
pathTriplet(c(.1, .1, .4, .4, .6, .9, .9, .6),
c(.1, .4, .4, .1, .6, .6, .9, .9),
"Disjoint rectangles")
popViewport()
pushViewport(viewport(layout.pos.row = 4))
pathTriplet(c(.1, .1, .6, .6, .4, .4, .9, .9),
c(.1, .6, .6, .1, .4, .9, .9, .4),
"Overlapping rectangles, both clockwise")
popViewport()
pushViewport(viewport(layout.pos.row = 5))
pathTriplet(c(.1, .1, .6, .6, .4, .9, .9, .4),
c(.1, .6, .6, .1, .4, .4, .9, .9),
"Overlapping rectangles, one clockwise, other anti-clockwise")
popViewport()
popViewport()
}
pathTest()
# Drawing multiple paths at once
holed_rect <- cbind(c(.15, .15, -.15, -.15, .1, .1, -.1, -.1),
c(.15, -.15, -.15, .15, .1, -.1, -.1, .1))
holed_rects <- rbind(
holed_rect + matrix(c(.7, .2), nrow = 8, ncol = 2, byrow = TRUE),
holed_rect + matrix(c(.7, .8), nrow = 8, ncol = 2, byrow = TRUE),
holed_rect + matrix(c(.2, .5), nrow = 8, ncol = 2, byrow = TRUE)
)
grid.newpage()
grid.path(x = holed_rects[, 1], y = holed_rects[, 2],
id = rep(1:6, each = 4), pathId = rep(1:3, each = 8),
gp = gpar(fill = c('red', 'blue', 'green')),
rule = 'evenodd')
# Not specifying pathId will treat all points as part of the same path, thus
# having same fill
grid.newpage()
grid.path(x = holed_rects[, 1], y = holed_rects[, 2],
id = rep(1:6, each = 4),
gp = gpar(fill = c('red', 'blue', 'green')),
rule = 'evenodd')
# }
```

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