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.ImageReadException;
022import org.apache.commons.imaging.common.ImageBuilder;
023
024public class PhotometricInterpreterYCbCr extends PhotometricInterpreter {
025
026    public PhotometricInterpreterYCbCr(final int samplesPerPixel,
027            final int[] bitsPerSample, final int predictor,
028            final int width, final int height) {
029        super(samplesPerPixel, bitsPerSample, predictor, width, height);
030    }
031
032    public static int limit(final int value, final int min, final int max) {
033        return Math.min(max, Math.max(min, value));
034    }
035
036    /**
037     * This method converts a YUV (aka YCbCr) colorspace to a RGB colorspace.
038     * This is handy when trying to reconstruct an image in Java from YCbCr
039     * transmitted data. This routine expects the data to fall in the standard
040     * PC 0..255 range per pixel, with the array dimensions corresponding to the
041     * imageWidth and imageHeight. These variables are either set manually in
042     * the case of a null constructor, or they are automatically calculated from
043     * the image parameter constructor.
044     *
045     * @param Y
046     *            The Y component set.
047     * @param Cb
048     *            The Cb component set.
049     * @param Cr
050     *            The Cr component set.
051     * @return R The R component.
052     */
053    public static int convertYCbCrtoRGB(final int Y, final int Cb, final int Cr) {
054        final double r1 = (((1.164 * (Y - 16.0))) + (1.596 * (Cr - 128.0)));
055        final double g1 = (((1.164 * (Y - 16.0))) - (0.813 * (Cr - 128.0)) - (0.392 * (Cb - 128.0)));
056        final double b1 = (((1.164 * (Y - 16.0))) + (2.017 * (Cb - 128.0)));
057
058        final int r = limit((int) r1, 0, 255);
059        final int g = limit((int) g1, 0, 255);
060        final int b = limit((int) b1, 0, 255);
061
062        final int alpha = 0xff;
063        final int rgb = (alpha << 24) | (r << 16) | (g << 8) | (b << 0);
064        return rgb;
065    }
066
067    @Override
068    public void interpretPixel(final ImageBuilder imageBuilder, final int[] samples, final int x,
069            final int y) throws ImageReadException, IOException {
070        final int Y = samples[0];
071        final int Cb = samples[1];
072        final int Cr = samples[2];
073        final double R = Y + 1.402 * (Cr - 128.0);
074        final double G = Y - 0.34414 * (Cb - 128.0) - 0.71414 * (Cr - 128.0);
075        final double B = Y + 1.772 * (Cb - 128.0);
076
077        final int red = limit((int) R, 0, 255);
078        final int green = limit((int) G, 0, 255);
079        final int blue = limit((int) B, 0, 255);
080
081        final int alpha = 0xff;
082        final int rgb = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
083        imageBuilder.setRGB(x, y, rgb);
084
085    }
086}