/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.imaging.formats.tiff.photometricinterpreters;
  
  import java.io.IOException;
  
  import org.apache.commons.imaging.ImagingException;
  import org.apache.commons.imaging.common.ImageBuilder;
  
  public class PhotometricInterpreterYCbCr extends PhotometricInterpreter {
  
      /**
       * 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
       * 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
       * imageHeight. These variables are either set manually in the case of a null constructor, or they are automatically calculated from the image parameter
       * constructor.
       *
       * @param y  The Y component set.
       * @param cb The Cb component set.
       * @param cr The Cr component set.
       * @return R The R component.
       */
      public static int convertYCbCrtoRGB(final int y, final int cb, final int cr) {
          final double r1 = 1.164 * (y - 16.0) + 1.596 * (cr - 128.0);
          final double g1 = 1.164 * (y - 16.0) - 0.813 * (cr - 128.0) - 0.392 * (cb - 128.0);
          final double b1 = 1.164 * (y - 16.0) + 2.017 * (cb - 128.0);
  
          final int r = limit((int) r1, 0, 255);
          final int g = limit((int) g1, 0, 255);
          final int b = limit((int) b1, 0, 255);
  
          final int alpha = 0xff;
          return alpha << 24 | r << 16 | g << 8 | b << 0;
      }
  
      public static int limit(final int value, final int min, final int max) {
          return Math.min(max, Math.max(min, value));
      }
  
      public PhotometricInterpreterYCbCr(final int samplesPerPixel, final int[] bitsPerSample, final int predictor, final int width, final int height) {
          super(samplesPerPixel, bitsPerSample, predictor, width, height);
      }
  
      @Override
      public void interpretPixel(final ImageBuilder imageBuilder, final int[] samples, final int x, final int y) throws ImagingException, IOException {
          final int Y = samples[0];
          final int cb = samples[1];
          final int cr = samples[2];
          final double r = Y + 1.402 * (cr - 128.0);
          final double g = Y - 0.34414 * (cb - 128.0) - 0.71414 * (cr - 128.0);
          final double b = Y + 1.772 * (cb - 128.0);
  
          final int red = limit((int) r, 0, 255);
          final int green = limit((int) g, 0, 255);
          final int blue = limit((int) b, 0, 255);
  
          final int alpha = 0xff;
          final int rgb = alpha << 24 | red << 16 | green << 8 | blue << 0;
          imageBuilder.setRgb(x, y, rgb);
  
      }
  }