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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.imaging.formats.png.transparencyfilters;
18  
19  import java.io.IOException;
20  
21  import org.apache.commons.imaging.ImageReadException;
22  import org.apache.commons.imaging.common.BinaryFileParser;
23  
24  public abstract class TransparencyFilter extends BinaryFileParser {
25      private final byte[] bytes;
26  
27      public TransparencyFilter(final byte[] bytes) {
28          this.bytes = bytes.clone();
29  
30      }
31  
32      public abstract int filter(int rgb, int index) throws ImageReadException,
33              IOException;
34  
35      /**
36       * @return a byte
37       */
38      public byte getByte(final int offset) {
39          return bytes[offset];
40      }
41  
42      /**
43       * @return the length
44       */
45      public int getLength() {
46          return bytes.length;
47      }
48  }