Function
Description
Transform linear pixel values using a custom function.
The given function is evaluated on linear pixel values, that is after raw pixels have been translated to normalized pixel values (see Image.Range) and after gamma correction has been applied (see Gamma). The expression may use all members of the default Tinman script. The following arguments are available to the function expression:
-
raw
The input pixel value (raw). -
lin
The input pixel value (linear) in the range [0..1]. -
A, B, C, D, E, F
Coefficients that can be used to transform between raw and linear pixel values:lin = pow(raw * A + B, C) raw = pow(lin, D) * E + F D = 1 / C E = 1 / A F = -B / A
where
raw
is the raw pixel value that is actually stored in the source image (e.g. [0..255] for 8-bit images) andlin
is the linear pixel value that is stored in the image scanline buffer.A
andB
represent the transformation from raw pixel values to normalized pixel values (see Image.Range);C
is the exponent that best approximates the performed gamma correction (see Gamma).
Fields / Optional
channel
The pixel channel the function shall be applied to. If Channel.Void, no transformation will be performed.