The function is only available if ImageMagick was compiled on a system with the FFTW library. http://www.fftw.org/

I need to add this to the documentation.

The error is: Call to undefined method

so it won't even work with imagemagick compiled with fftw support. Please check that this is indeed the case before adding misleading comments to the documentation.

Thank you for the feedback. Here is an example of it working: http://phpimagick.com/Imagick/forwardFourierTransformImage

I've double-checked and the method Imagick::forwardfouriertransformimage is definitely not compiled into the Imagick class, if the functions provided by FFTW are not available through ImageMagick.

It is a case that the method is not available, rather than being available and just not working if the FFTW stuff isn't available.

I should have said, checking for whether the method is available before hand is the appropriate thing to do if you are unsure whether the version of Imagick installed is going to have the fourier functions installed or not.

$im = new Imagick ("compass_model.png");
if (method_exists($im, 'forwardFourierTransformimage') == false) {
	throw new Exception("Installed version of Imagick does not support Fourier functions.");
}
$imagick->forwardFourierTransformimage (true);
$imagick->writeImages ("fourier_test.png", false);