R: Customising grid Drawing

drawDetails {grid} | R Documentation

## Customising grid Drawing

### Description

These generic hook functions are called whenever a grid grob is drawn. They provide an opportunity for customising the drawing of a new class derived from grob (or gTree).

### Usage

    drawDetails(x, recording)
    preDrawDetails(x)
    postDrawDetails(x)

### Arguments

`x` | A grid grob.
`recording` | A logical value indicating whether a grob is being added to the display list or redrawn from the display list.

### Details

These functions are called by the `grid.draw` methods for grobs and gTrees.

`preDrawDetails` is called first during the drawing of a grob. This is where any additional viewports should be pushed (see, for example, `grid:::preDrawDetails.frame`). Note that the default behaviour for grobs is to push any viewports in the `vp` slot, and for gTrees is to also push and up any viewports in the `childrenvp` slot so there is typically nothing to do here.

`drawDetails` is called next and is where any additional calculations and graphical output should occur (see, for example, `grid:::drawDetails.xaxis`. Note that the default behaviour for gTrees is to draw all grobs in the `children` slot so there is typically nothing to do here.

`postDrawDetails` is called last and should reverse anything done in `preDrawDetails` (i.e., pop or up any viewports that were pushed; again, see, for example, `grid:::postDrawDetails.frame`). Note that the default behaviour for grobs is to pop any viewports that were pushed so there is typically nothing to do here.

Note that `preDrawDetails` and `postDrawDetails` are also called in the calculation of `"grobwidth"` and `"grobheight"` units.

### Value

None of these functions are expected to return a value.

### Author(s)

Paul Murrell

### See Also

`grid.draw`

[Package grid version 3.1.2 Index]