feSpotLight: 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

A numeric vector or unit object specifying the x-location of the light source.

A numeric vector or unit object specifying the y-location of the light source.

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.

Value

An fe.spot.light object.

Details

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

References

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

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