grobCoords {grid} | R Documentation |

## Calculate Points on the Perimeter of a Grob

### Description

These functions calculate points along the perimeter (or length) of a grob.

### Usage

```
grobCoords(x, closed, ...)
grobPoints(x, closed, ...)
isClosed(x, ...)
```

### Arguments

`x` |
A grob object. |

`closed` |
Whether we are asking for points along the perimeter of a closed object or points along the length of an open object. Some grobs (e.g., X-splines) can do both. This defaults to |

`...` |
Arguments to be used by methods. |

### Details

The difference between `grobCoords`

and `grobPoints`

is that `grobCoords`

performs all pre- and post-drawing operations
on the grob that would normally occur if the grob was being drawn,
then calls `grobPoints`

. So the former takes into account
any `vp`

and `gp`

settings on the grob. This means
that users should usually only want to call `grobCoords`

;
only (expert) developers may have a need to call `grobPoints`

.

Custom grobs can write their own methods for `grobPoints`

(see `gridCoords`

).

The `isClosed`

function returns `TRUE`

or `FALSE`

to indicate whether a grob is a closed shape. The default response
is `TRUE`

, unless a method has been defined otherwise
(e.g., for lines and line segments).

### Value

Either a `"GridGrobCoords"`

object
(a list of lists with components `x`

and `y`

) or
a `"GridGTreeCoords"`

object
(a list of `"GridGrobCoords"`

and/or `"GridGTreeCoords"`

objects).

All locations are in inches relative to the current grid viewport.

### Author(s)

Paul Murrell

*grid*version 4.4.0 Index]