blend_colors {colorplane}

blend two color planes

Description

given two color planes, generate a new color plane by blending the colors using the supplied alpha multiplier.

Usage

blend_colors(bottom, top, alpha)

## S4 method for signature 'ColorPlane,ColorPlane,numeric'
blend_colors(bottom, top, alpha = 1)

## S4 method for signature 'ColorPlane,ColorPlane,missing'
blend_colors(bottom, top)

## S4 method for signature 'HexColorPlane,RGBColorPlane,numeric'
blend_colors(bottom, top, alpha)

## S4 method for signature 'HexColorPlane,ConstantColorPlane,numeric'
blend_colors(bottom, top, alpha = 1)

Arguments

bottom

the bottom color plane

top

the top color plane

alpha

the alpha overlay value.

Details

The functions in this package blend colors based on the "over" operator where 'top' if foreground and 'bottom' is background.

Value

a new ColorPlane instance with 'top' and 'bottom' alpha-blended.

References

https://en.wikipedia.org/wiki/Alpha_compositing

Examples

top <- IntensityColorPlane(1:5, cols=rainbow(5))
bottom <- IntensityColorPlane(1:5, cols=rev(rainbow(5)))

top <- map_colors(top)
bottom <- map_colors(bottom)
bc <- blend_colors(bottom, top, .5)