feSpotLight: Create a Spot Light Source
In sachsmc/gridSVG: Export grid graphics as SVG

Description Usage Arguments Details Value Author(s) References See Also

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

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, ...)

`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`.