src/main/java/org/apache/commons/imaging/formats/transparencyfilters/TransparencyFilterTrueColor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.imaging.formats.transparencyfilters;

import java.io.ByteArrayInputStream;
import java.io.IOException;

import org.apache.commons.imaging.ImageReadException;

public class TransparencyFilterTrueColor extends TransparencyFilter
{
    private final int transparent_red;
    private final int transparent_green;
    private final int transparent_blue;
    private final int transparent_color;

    public TransparencyFilterTrueColor(byte bytes[]) throws ImageReadException,
            IOException
    {
        super(bytes);

        ByteArrayInputStream is = new ByteArrayInputStream(bytes);
        transparent_red = read2Bytes("transparent_red", is,
                "tRNS: Missing transparent_color");
        transparent_green = read2Bytes("transparent_green", is,
                "tRNS: Missing transparent_color");
        transparent_blue = read2Bytes("transparent_blue", is,
                "tRNS: Missing transparent_color");

        transparent_color = ((0xff & transparent_red) << 16)
                | ((0xff & transparent_green) << 8)
                | ((0xff & transparent_blue) << 0);

    }

    @Override
    public int filter(int rgb, int sample) throws ImageReadException,
            IOException
    {
        if ((0x00ffffff & rgb) == transparent_color)
            return 0x00;

        return rgb;
    }
}