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grid.lines: Draw Lines in a Grid Viewport

grid.lines

R Documentation

Draw Lines in a Grid Viewport

Description

These functions create and draw a series of lines.

Usage

grid.lines(x = unit(c(0, 1), "npc"),
          y = unit(c(0, 1), "npc"),
          default.units = "npc",
          arrow = NULL, name = NULL,
          gp=gpar(), draw = TRUE, vp = NULL)
linesGrob(x = unit(c(0, 1), "npc"),
          y = unit(c(0, 1), "npc"),
          default.units = "npc",
          arrow = NULL, name = NULL,
          gp=gpar(), vp = NULL)
grid.polyline(...)
polylineGrob(x = unit(c(0, 1), "npc"),
             y = unit(c(0, 1), "npc"),
             id=NULL, id.lengths=NULL,
             default.units = "npc",
             arrow = NULL, name = NULL,
             gp=gpar(), vp = NULL)

Arguments

`x`	A numeric vector or unit object specifying x-values.
`y`	A numeric vector or unit object specifying y-values.
`default.units`	A string indicating the default units to use if `x` or `y` are only given as numeric vectors.
`arrow`	A list describing arrow heads to place at either end of the line, as produced by the `arrow` function.
`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.
`draw`	A logical value indicating whether graphics output should be produced.
`vp`	A Grid viewport object (or NULL).
`id`	A numeric vector used to separate locations in `x` and `y` into multiple lines. All locations with the same `id` belong to the same line.
`id.lengths`	A numeric vector used to separate locations in `x` and `y` into multiple lines. Specifies consecutive blocks of locations which make up separate lines.
`...`	Arguments passed to `polylineGrob`.

Details

The first two functions create a lines grob (a graphical object describing lines), and grid.lines draws the lines (if draw is TRUE).

The second two functions create or draw a polyline grob, which is just like a lines grob, except that there can be multiple distinct lines drawn.

Value

A lines grob or a polyline grob. grid.lines returns a lines grob invisibly.

Author(s)

Paul Murrell

Examples

grid.lines()
# Using id (NOTE: locations are not in consecutive blocks)
grid.newpage()
grid.polyline(x=c((0:4)/10, rep(.5, 5), (10:6)/10, rep(.5, 5)),
             y=c(rep(.5, 5), (10:6/10), rep(.5, 5), (0:4)/10),
             id=rep(1:5, 4),
             gp=gpar(col=1:5, lwd=3))
# Using id.lengths
grid.newpage()
grid.polyline(x=outer(c(0, .5, 1, .5), 5:1/5),
             y=outer(c(.5, 1, .5, 0), 5:1/5),
             id.lengths=rep(4, 5),
             gp=gpar(col=1:5, lwd=3))