colorSpec (version 0.5-2)

DisplayRGB: Compute Display RGB from Linear RGB

Description

All RGB displays have a non-linear "gamma function" of some sort. This function converts from linear RGB to an RGB appropriate for the gamma function of the display.

Usage

DisplayRGBfromLinearRGB( RGB, gamma='sRGB' )

Arguments

RGB

linear RGB values organized as a vector or matrix of any size; all 3 channels are treated the same way so size does not matter

gamma

either the string 'sRGB' or a positive number giving the gamma of the display.

Value

• The function first clamps the input RGB to the interval [0,1]. If gamma='sRGB' (not case-sensitive) it then maps [0,1] to [0,1] using the special piecewise-defined sRGB function, see Wikipedia. In case gamma is a positive number, the function raises all values to the power 1/gamma. The dimensions and names of the input are copied to the output. In case of error, the function returns the clamped input values.

source

Wikipedia. sRGB. http://en.wikipedia.org/wiki/sRGB

See Also

RGBfromXYZ

Examples

DisplayRGBfromLinearRGB( c(0.2, 0.5) )
# [1] 0.4845292 0.7353570     #  this is display sRGB, in [0,1]

DisplayRGBfromLinearRGB( c(-0.1, 0.2, 0.5, 1), 2.2 )
# [1] 0.0000000 0.4811565 0.7297401 1.0000000    #  gamma=2.2

x = seq( 0, 1, len=101)
plot( x, DisplayRGBfromLinearRGB(x), type='l' )