Method doMasking

ij/src/main/java/ij/plugin/FFT.java:370–402

(FHT ip)

	}
	
	void doMasking(FHT ip) {
		if (stackSize>1)
			return;
		float[] fht = (float[])ip.getPixels();
		ImageProcessor mask = imp.getProcessor();
		int bitDepth = mask.getBitDepth();
		mask = mask.convertToByte(false);
		if (mask.getWidth()!=ip.getWidth() || mask.getHeight()!=ip.getHeight())
			return;
		mask.resetRoi();
		ImageStatistics stats = mask.getStats();
		if (stats.histogram[0]==0 && stats.histogram[255]==0) {
			if (bitDepth==8 && ip.powerSpectrumMean!=stats.mean)
				IJ.showMessage("Inverse FFT", "No pixels have been set to 0 (black) or\n255 (white) so filtering will not be done.");
			return;
		}
		boolean passMode = stats.histogram[255]!=0;
		IJ.showStatus("Masking: "+(passMode?"pass":"filter"));
		mask = mask.duplicate();
		if (passMode)
			changeValuesAndSymmetrize(mask, (byte)255, (byte)0); //0-254 become 0
		else
			changeValuesAndSymmetrize(mask, (byte)0, (byte)255); //1-255 become 255
		for (int i=0; i<3; i++)
			smooth(mask);
		if (IJ.debugMode || IJ.altKeyDown())
			new ImagePlus("mask", mask.duplicate()).show();
		swapQuadrants(mask);
		byte[] maskPixels = (byte[])mask.getPixels();
		for (int i=0; i<fht.length; i++) {
			fht[i] = (float)(fht[i]*(maskPixels[i]&255)/255.0);
		}
	}

	// Change pixels not equal to v1 to the new value v2.
	// For pixels equal to v1, also the symmetry-equivalent pixel is set to v1