001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.imaging.formats.tiff.photometricinterpreters;
018
019import java.io.IOException;
020
021import org.apache.commons.imaging.ImagingException;
022import org.apache.commons.imaging.common.ImageBuilder;
023
024public class PhotometricInterpreterYCbCr extends AbstractPhotometricInterpreter {
025
026    /**
027     * This method converts a YUV (aka YCbCr) colorspace to a RGB colorspace. This is handy when trying to reconstruct an image in Java from YCbCr transmitted
028     * data. This routine expects the data to fall in the standard PC 0..255 range per pixel, with the array dimensions corresponding to the imageWidth and
029     * imageHeight. These variables are either set manually in the case of a null constructor, or they are automatically calculated from the image parameter
030     * constructor.
031     *
032     * @param y  The Y component set.
033     * @param cb The Cb component set.
034     * @param cr The Cr component set.
035     * @return R The R component.
036     */
037    public static int convertYCbCrtoRGB(final int y, final int cb, final int cr) {
038        final double r1 = 1.164 * (y - 16.0) + 1.596 * (cr - 128.0);
039        final double g1 = 1.164 * (y - 16.0) - 0.813 * (cr - 128.0) - 0.392 * (cb - 128.0);
040        final double b1 = 1.164 * (y - 16.0) + 2.017 * (cb - 128.0);
041
042        final int r = limit((int) r1, 0, 255);
043        final int g = limit((int) g1, 0, 255);
044        final int b = limit((int) b1, 0, 255);
045
046        final int alpha = 0xff;
047        return alpha << 24 | r << 16 | g << 8 | b << 0;
048    }
049
050    public static int limit(final int value, final int min, final int max) {
051        return Math.min(max, Math.max(min, value));
052    }
053
054    public PhotometricInterpreterYCbCr(final int samplesPerPixel, final int[] bitsPerSample, final int predictor, final int width, final int height) {
055        super(samplesPerPixel, bitsPerSample, predictor, width, height);
056    }
057
058    @Override
059    public void interpretPixel(final ImageBuilder imageBuilder, final int[] samples, final int x, final int y) throws ImagingException, IOException {
060        final int Y = samples[0];
061        final int cb = samples[1];
062        final int cr = samples[2];
063        final double r = Y + 1.402 * (cr - 128.0);
064        final double g = Y - 0.34414 * (cb - 128.0) - 0.71414 * (cr - 128.0);
065        final double b = Y + 1.772 * (cb - 128.0);
066
067        final int red = limit((int) r, 0, 255);
068        final int green = limit((int) g, 0, 255);
069        final int blue = limit((int) b, 0, 255);
070
071        final int alpha = 0xff;
072        final int rgb = alpha << 24 | red << 16 | green << 8 | blue << 0;
073        imageBuilder.setRgb(x, y, rgb);
074
075    }
076}