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.ImagingException;
22
23 public class TransparencyFilterIndexedColor extends AbstractTransparencyFilter {
24
25 public TransparencyFilterIndexedColor(final byte[] bytes) {
26 super(bytes);
27 }
28
29 @Override
30 public int filter(final int rgb, final int index) throws ImagingException, IOException {
31 final int length = getLength();
32 if (index >= length) { // TODO see below - is this check correct?
33 return rgb;
34 }
35
36 if (index < 0 || index > length) { // TODO check for > length cannot be true because of check above
37 throw new ImagingException("TransparencyFilterIndexedColor index: " + index + ", bytes.length: " + length);
38 }
39
40 final int alpha = getByte(index);
41 return (0xff & alpha) << 24 | 0x00ffffff & rgb;
42 }
43 }