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/*
* 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.
*/
/* $Id$ */
package org.apache.fop.render.pcl;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.IndexColorModel;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.ParameterBlock;
import javax.media.jai.ColorCube;
import javax.media.jai.ImageLayout;
import javax.media.jai.JAI;
import javax.media.jai.KernelJAI;
import javax.media.jai.LookupTableJAI;
import javax.media.jai.PlanarImage;
/**
* Implementation of the MonochromeBitmapConverter which uses Java Advanced Imaging (JAI)
* to convert grayscale bitmaps to monochrome bitmaps. JAI provides better dithering options
* including error diffusion dithering.
* <p>
* If you call setHint("quality", "true") on the instance you can enabled error diffusion
* dithering which produces a nicer result but is also a lot slower.
*/
public class JAIMonochromeBitmapConverter implements
MonochromeBitmapConverter {
private boolean isErrorDiffusion = false;
/** {@inheritDoc} */
public void setHint(String name, String value) {
if ("quality".equalsIgnoreCase(name)) {
isErrorDiffusion = "true".equalsIgnoreCase(value);
}
}
/** {@inheritDoc} */
public RenderedImage convertToMonochrome(BufferedImage img) {
if (img.getColorModel().getColorSpace().getNumComponents() != 1) {
throw new IllegalArgumentException("Source image must be a grayscale image!");
}
// Load the ParameterBlock for the dithering operation
// and set the operation name.
ParameterBlock pb = new ParameterBlock();
pb.addSource(img);
String opName = null;
if (isErrorDiffusion) {
opName = "errordiffusion";
LookupTableJAI lut = new LookupTableJAI(new byte[] {(byte)0x00, (byte)0xff});
pb.add(lut);
pb.add(KernelJAI.ERROR_FILTER_FLOYD_STEINBERG);
} else {
opName = "ordereddither";
//Create the color cube.
ColorCube colorMap = ColorCube.createColorCube(DataBuffer.TYPE_BYTE,
0, new int[] {2});
pb.add(colorMap);
pb.add(KernelJAI.DITHER_MASK_441);
}
//Create an image layout for a monochrome b/w image
ImageLayout layout = new ImageLayout();
byte[] map = new byte[] {(byte)0x00, (byte)0xff};
ColorModel cm = new IndexColorModel(1, 2, map, map, map);
layout.setColorModel(cm);
// Create a hint containing the layout.
RenderingHints hints = new RenderingHints(JAI.KEY_IMAGE_LAYOUT, layout);
// Dither the image.
PlanarImage dst = JAI.create(opName, pb, hints);
//Convert it to a BufferedImage
return dst.getAsBufferedImage();
}
}
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