R: Create a Spot Light Source

feSpotLight {gridSVG} | R Documentation

## Create a Spot Light Source

### Description

This filter primitive defines a spot light source that can be used within a lighting filter primitive: `feDiffuseLighting` or `feSpecularLighting`.

### Usage

    feSpotLight(x = unit(0, "npc"), y = unit(0, "npc"), z = unit(0, "npc"),
                pointsAtX = unit(1, "npc"), pointsAtY = unit(1, "npc"),
                pointsAtZ = unit(0, "npc"), zdim = "x",
                default.units = "npc", specularExponent = 1,
                limitingConeAngle = NA, ...)

### Arguments

`x` | A numeric vector or unit object specifying the x-location of the light source.
`y` | A numeric vector or unit object specifying the y-location of the light source.
`z` | A numeric vector or unit object specifying the z-location of the light source.
`pointsAtX` | A numeric vector or unit object specifying the x-location that the light points at.
`pointsAtY` | A numeric vector or unit object specifying the y-location that the light points at.
`pointsAtZ` | A numeric vector or unit object specifying the z-location that the light points at.
`zdim` | Either `"x"` or `"y"`. Determines the dimension to which `z` and `pointsAtZ` will be located relative to. This is necessary because R graphics has no concept of a z-dimension.
`default.units` | A string indicating the default units to use if `x`, `y`, `z`, `pointsAtX`, `pointsAtY`, `pointsAtZ` are only given as numeric vectors.
`specularExponent` | Exponent value controlling the focus for the light source.
`limitingConeAngle` | If `NA`, no limiting cone is applied, otherwise a limiting cone which restricts the region where the light is projected. No light is projected outside the cone. `limitingConeAngle` represents the angle in degrees between the spot light axis (i.e. the axis between the light source and the point to which it is pointing at) and the spot light cone.
`...` | Further arguments to be passed onto `fe`.

### Details

For more information about this primitive, consult the reference to the SVG specification.

### Value

An `fe.spot.light` object.

### Author(s)

Simon Potter

### References

http://www.w3.org/TR/SVG/filters.html#feSpotLightElement

### See Also

`filterEffect`, `fe`, `feDiffuseLighting`, `feSpecularLighting`.

[Package gridSVG version 1.6-0 Index]