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 * Image processing operations for SciJava Ops.
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package org.scijava.ops.image.filter.ifft;

import java.util.function.Function;

import net.imglib2.RandomAccessibleInterval;
import net.imglib2.algorithm.fft2.FFTMethods;
import net.imglib2.type.numeric.ComplexType;
import net.imglib2.type.numeric.RealType;

import org.scijava.function.Computers;
import org.scijava.ops.spi.OpDependency;

/**
 * Inverse FFT computer that operates on an RAI and wraps FFTMethods. The input
 * and output size must conform to supported FFT size. Use
 * {@link org.scijava.ops.image.filter.fftSize.ComputeFFTSize} to calculate the
 * supported FFT size.
 *
 * @author Brian Northan
 * @param <C>
 * @param <T>
 * @implNote op names='filter.ifft'
 */
public class IFFTMethodsOpC<C extends ComplexType<C>, T extends RealType<T>>
	implements
	Computers.Arity1<RandomAccessibleInterval<C>, RandomAccessibleInterval<T>>
{

	@OpDependency(name = "copy.rai")
	private Function<RandomAccessibleInterval<C>, RandomAccessibleInterval<C>> copyOp;

	/**
	 * Compute an ND inverse FFT
	 */
	/**
	 * TODO
	 *
	 * @param input
	 * @param output
	 */
	@Override
	public void compute(final RandomAccessibleInterval<C> input,
		final RandomAccessibleInterval<T> output)
	{
		if (!conforms(input)) throw new IllegalArgumentException(
			"The input image dimensions to not conform to a supported FFT size");

		final var temp = copyOp.apply(input);

		for (var d = input.numDimensions() - 1; d > 0; d--)
			FFTMethods.complexToComplex(temp, d, false, true);

		FFTMethods.complexToReal(temp, output, FFTMethods.unpaddingIntervalCentered(
			temp, output), 0, true);
	}

	/**
	 * Make sure that the input size conforms to a supported FFT size.
	 */
	public boolean conforms(RandomAccessibleInterval<C> input) {

        var paddedDimensions = new long[input.numDimensions()];
        var realDimensions = new long[input.numDimensions()];

        var fastSizeConforms = false;

		FFTMethods.dimensionsComplexToRealFast(input, paddedDimensions,
			realDimensions);

		if (FFTMethods.dimensionsEqual(input, paddedDimensions) == true) {
			fastSizeConforms = true;
		}

        var smallSizeConforms = false;

		FFTMethods.dimensionsComplexToRealSmall(input, paddedDimensions,
			realDimensions);

		if (FFTMethods.dimensionsEqual(input, paddedDimensions) == true) {
			smallSizeConforms = true;
		}

		return fastSizeConforms || smallSizeConforms;

	}

}
