se.llbit.png.IHDR Maven / Gradle / Ivy

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Minecraft mapping and rendering tool
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/* Copyright (c) 2012-2015 Jesper Öqvist 
 *
 * This file is part of Chunky.
 *
 * Chunky is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Chunky is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with Chunky.  If not, see .
 */
package se.llbit.png;

import java.io.DataOutputStream;
import java.io.IOException;

/**
 * @author Jesper Öqvist 
 */
public class IHDR extends PngChunk {

  /**
   * The PNG chunk type identifier
   */
  public static final int CHUNK_TYPE = 0x49484452;

  private static final int BIT_DEPTH = 8;
  protected static final int COLOR_TYPE_RGB = 2; // Each pixel is an RGB triple.
  protected static final int COLOR_TYPE_RGBA = 6; // Each pixel is an RGBA quad.
  private static final int COMPRESSION_METHOD = 0; // Deflate/inflate compression.
  private static final int FILTER_METHOD = 0;
  private static final int INTERLACE_METHOD = 0;
  private int crc;
  private final int width;
  private final int height;
  private final int colorType;
  private final int bitDepth;

  public IHDR(int width, int height) {
    this(width, height, COLOR_TYPE_RGB, BIT_DEPTH);
  }

  public IHDR(int width, int height, int colorType) {
    this(width, height, colorType, BIT_DEPTH);
  }

  public IHDR(int width, int height, int colorType, int bitDepth) {
    this.width = width;
    this.height = height;
    this.colorType = colorType;
    this.bitDepth = bitDepth;
  }

  @Override public int getChunkType() {
    return CHUNK_TYPE;
  }

  @Override protected void writeChunkData(DataOutputStream out) throws IOException {
    CrcOutputStream crcOutputStream = new CrcOutputStream();
    DataOutputStream crcOut = new DataOutputStream(crcOutputStream);

    crcOut.writeInt(CHUNK_TYPE);

    crcOut.writeInt(width);
    out.writeInt(width);

    crcOut.writeInt(height);
    out.writeInt(height);

    crcOut.writeByte(bitDepth);
    out.writeByte(bitDepth);

    crcOut.writeByte(colorType);
    out.writeByte(colorType);

    crcOut.writeByte(COMPRESSION_METHOD);
    out.writeByte(COMPRESSION_METHOD);

    crcOut.writeByte(FILTER_METHOD);
    out.writeByte(FILTER_METHOD);

    crcOut.writeByte(INTERLACE_METHOD);
    out.writeByte(INTERLACE_METHOD);

    crc = crcOutputStream.getCRC();
    crcOut.close();
  }

  @Override public int getChunkLength() {
    return 13;
  }

  @Override public int getChunkCRC() {
    return crc;
  }


}