Legacy ImageMagick Discussions Archive

What is the significance/usage of the noise and threshold operators in the -evaluate list of functions on the options page? Are they meaningful in the context of -evaluate and if so, how are they different from the normal noise and threshold functions?

also with

convert -list evaluate

Add
And
Divide
Gaussian-noise
Impluse-noise
Laplacian-noise
LeftShift
Log
Max
Min
Multiplicative-noise
Multiply
Or
PoissonNoise
Pow
RightShift
Set
Subtract
Threshold
Threshold-black
Threshold-white
Uniform-noise
Xor

The threshold arguments for the -evaluate option behave the same as the threshold options (i.e. -white-threshold).

magick wrote:The threshold arguments for the -evaluate option behave the same as the threshold options (i.e. -white-threshold).

But why the duplication of the noise and threshold functions in -evaluate?

They were added simply for completeness sake for developers that want to use the EvaluateImage() methods exclusively.

It really depends on how you are thinking about your images.

As a image, or as just a array of numbers!

All the -evaluate methods should however be defined in the offical command line options page. If it is not defined or unclear, please let us know and we will try to make it clear. This is something that has improved enormously in the couple of years.

IM Examples link all text references of options to either a example set that talks about that option, or the command line options page.
You can also make use of the IM examples References Page
http://www.imagemagick.org/Usage/reference.html
to look at the offical reference or the best examples of that option in IM examples.