grid.path

0th

Percentile

Draw a Path

These functions create and draw one or more paths. The final point of a path will automatically be connected to the initial point.

Keywords
dplot
Usage
pathGrob(x, y,
         id=NULL, id.lengths=NULL,
         pathId=NULL, pathId.lengths=NULL,
         rule="winding",
         default.units="npc",
         name=NULL, gp=gpar(), vp=NULL)
grid.path(…)
Arguments
x

A numeric vector or unit object specifying x-locations.

y

A numeric vector or unit object specifying y-locations.

id

A numeric vector used to separate locations in x and y into sub-paths. All locations with the same id belong to the same sub-path.

id.lengths

A numeric vector used to separate locations in x and y into sub-paths. Specifies consecutive blocks of locations which make up separate sub-paths.

pathId

A numeric vector used to separate locations in x and y into distinct paths. All locations with the same pathId belong to the same path.

pathId.lengths

A numeric vector used to separate locations in x and y into paths. Specifies consecutive blocks of locations which make up separate paths.

rule

A character value specifying the fill rule: either "winding" or "evenodd".

default.units

A string indicating the default units to use if x or y are only given as numeric vectors.

name

A character identifier.

gp

An object of class gpar, typically the output from a call to the function gpar. This is basically a list of graphical parameter settings.

vp

A Grid viewport object (or NULL).

Arguments passed to pathGrob().

Details

Both functions create a path grob (a graphical object describing a path), but only grid.path draws the path (and then only if draw is TRUE).

A path is like a polygon except that the former can contain holes, as interpreted by the fill rule; these fill a region if the path border encircles it an odd or non-zero number of times, respectively.

Not all graphics devices support this function: for example xfig and pictex do not.

Value

A grob object.

See Also

Grid, viewport

Aliases
  • grid.path
  • pathGrob
Examples
library(grid) # 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') # }
Documentation reproduced from package grid, version 3.6.1, License: Part of R 3.6.1

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