R: Draw Lines in a Grid Viewport

grid.lines {grid} | 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

### See Also

Grid, `viewport`, `arrow`

### 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))

[Package grid version 2.6.2 Index]