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.png.transparencyfilters; 018 019import static org.apache.commons.imaging.common.BinaryFunctions.read2Bytes; 020 021import java.io.ByteArrayInputStream; 022import java.io.IOException; 023 024import org.apache.commons.imaging.ImagingException; 025 026public final class TransparencyFilterGrayscale extends AbstractTransparencyFilter { 027 private final int transparentColor; 028 029 public TransparencyFilterGrayscale(final byte[] bytes) throws IOException { 030 super(bytes); 031 032 final ByteArrayInputStream is = new ByteArrayInputStream(bytes); 033 transparentColor = read2Bytes("transparentColor", is, "tRNS: Missing transparentColor", getByteOrder()); 034 } 035 036 @Override 037 public int filter(final int rgb, final int index) throws ImagingException, IOException { 038 if (index != transparentColor) { 039 return rgb; 040 } 041 return 0x00; 042 } 043}