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; 022 023public class TransparencyFilterIndexedColor extends AbstractTransparencyFilter { 024 025 public TransparencyFilterIndexedColor(final byte[] bytes) { 026 super(bytes); 027 } 028 029 @Override 030 public int filter(final int rgb, final int index) throws ImagingException, IOException { 031 final int length = getLength(); 032 if (index >= length) { // TODO see below - is this check correct? 033 return rgb; 034 } 035 036 if (index < 0 || index > length) { // TODO check for > length cannot be true because of check above 037 throw new ImagingException("TransparencyFilterIndexedColor index: " + index + ", bytes.length: " + length); 038 } 039 040 final int alpha = getByte(index); 041 return (0xff & alpha) << 24 | 0x00ffffff & rgb; 042 } 043}