    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}