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 java.io.IOException;
020
021import org.apache.commons.imaging.ImagingException;
022import org.apache.commons.imaging.common.BinaryFileParser;
023
024public abstract class AbstractTransparencyFilter extends BinaryFileParser {
025
026    private final byte[] bytes;
027
028    /**
029     * Constructs a new instance.
030     *
031     * @param bytes bytes.
032     */
033    public AbstractTransparencyFilter(final byte[] bytes) {
034        this.bytes = bytes.clone();
035    }
036
037    public abstract int filter(int rgb, int index) throws ImagingException, IOException;
038
039    /**
040     * Gets the byte at the given offset.
041     *
042     * @param offset offset.
043     * @return a byte.
044     */
045    public byte getByte(final int offset) {
046        return bytes[offset];
047    }
048
049    /**
050     * Gets the length.
051     *
052     * @return the length
053     */
054    public int getLength() {
055        return bytes.length;
056    }
057}