/*
* 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.wicket.extensions.markup.html.image.resource;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.imageio.ImageIO;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.request.resource.DynamicImageResource;
import org.apache.wicket.request.resource.IResource;
import org.apache.wicket.response.ByteArrayResponse;
import org.apache.wicket.util.io.IOUtils;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.time.Time;
/**
* Image resource that dynamically scales the given original resource to a thumbnail. It is scaled
* either using the given maxSize as width or height, depending on its shape. If both the width and
* height are less than maxSize, no scaling is performed.
*
* @author Eelco Hillenius
* @author Eugene Kamenev
*/
public class ThumbnailImageResource extends DynamicImageResource
{
private static final long serialVersionUID = 1L;
/** the unscaled, original image resource. */
private final IResource unscaledImageResource;
/** maximum size (width or height) for resize operation. */
private final int maxSize;
/** the cached byte array of the thumbnail. */
private transient byte[] thumbnail;
/**
* Construct.
*
* @param unscaledImageResource
* the unscaled, original image resource. Must be not null
* @param maxSize
* maximum size (width or height) for resize operation
*/
public ThumbnailImageResource(final IResource unscaledImageResource, final int maxSize)
{
Args.notNull(unscaledImageResource, "unscaledImageResource");
this.unscaledImageResource = unscaledImageResource;
this.maxSize = maxSize;
}
/**
* @return The image data for this dynamic image
*/
@Override
protected byte[] getImageData(final Attributes attributes)
{
if (thumbnail == null)
{
final BufferedImage image = getScaledImageInstance(attributes);
thumbnail = toImageData(image);
setLastModifiedTime(Time.now());
}
return thumbnail;
}
/**
* get resized image instance.
*
* @param attributes
*
* @return BufferedImage
*/
protected BufferedImage getScaledImageInstance(final Attributes attributes)
{
InputStream is = null;
BufferedImage originalImage = null;
try
{
// read original image
ByteArrayResponse byteResponse = new ByteArrayResponse();
Attributes dispatchAttributes = new Attributes(attributes.getRequest(), byteResponse, attributes.getParameters());
unscaledImageResource.respond(dispatchAttributes);
is = new ByteArrayInputStream(byteResponse.getBytes());
originalImage = ImageIO.read(is);
if (originalImage == null)
{
throw new IOException("Unable to read unscaled image");
}
}
catch (IOException e)
{
throw new WicketRuntimeException(e);
}
finally
{
IOUtils.closeQuietly(is);
}
int originalWidth = originalImage.getWidth();
int originalHeight = originalImage.getHeight();
if ((originalWidth > maxSize) || (originalHeight > maxSize))
{
final int newWidth;
final int newHeight;
if (originalWidth > originalHeight)
{
newWidth = maxSize;
newHeight = (maxSize * originalHeight) / originalWidth;
}
else
{
newWidth = (maxSize * originalWidth) / originalHeight;
newHeight = maxSize;
}
// http://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html
BufferedImage dimg = new BufferedImage(newWidth, newHeight, originalImage.getType());
Graphics2D g = dimg.createGraphics();
try
{
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.drawImage(originalImage, 0, 0, newWidth, newHeight, 0, 0, originalWidth,
originalHeight, null);
}
finally
{
g.dispose();
}
return dimg;
}
// no need for resizing
return originalImage;
}
}