/**
* The contents of this file are subject to the license and copyright
* detailed in the LICENSE and NOTICE files at the root of the source
* tree and available online at
*
* http://www.dspace.org/license/
*/
package org.dspace.app.mediafilter;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.image.*;
import java.awt.RenderingHints;
import java.awt.Transparency;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import javax.imageio.ImageIO;
import org.dspace.core.ConfigurationManager;
/**
* Filter image bitstreams, scaling the image to be within the bounds of
* thumbnail.maxwidth, thumbnail.maxheight, the size we want our thumbnail to be
* no bigger than. Creates only JPEGs.
*
* @author Jason Sherman <jsherman@usao.edu>
*/
public class JPEGFilter extends MediaFilter implements SelfRegisterInputFormats
{
public String getFilteredName(String oldFilename)
{
return oldFilename + ".jpg";
}
/**
* @return String bundle name
*
*/
public String getBundleName()
{
return "THUMBNAIL";
}
/**
* @return String bitstreamformat
*/
public String getFormatString()
{
return "JPEG";
}
/**
* @return String description
*/
public String getDescription()
{
return "Generated Thumbnail";
}
/**
* @param source
* source input stream
*
* @return InputStream the resulting input stream
*/
public InputStream getDestinationStream(InputStream source)
throws Exception
{
// read in bitstream's image
BufferedImage buf = ImageIO.read(source);
// get config params
float xmax = (float) ConfigurationManager
.getIntProperty("thumbnail.maxwidth");
float ymax = (float) ConfigurationManager
.getIntProperty("thumbnail.maxheight");
boolean blurring = (boolean) ConfigurationManager
.getBooleanProperty("thumbnail.blurring");
boolean hqscaling = (boolean) ConfigurationManager
.getBooleanProperty("thumbnail.hqscaling");
// now get the image dimensions
float xsize = (float) buf.getWidth(null);
float ysize = (float) buf.getHeight(null);
// if verbose flag is set, print out dimensions
// to STDOUT
if (MediaFilterManager.isVerbose)
{
System.out.println("original size: " + xsize + "," + ysize);
}
// scale by x first if needed
if (xsize > xmax)
{
// calculate scaling factor so that xsize * scale = new size (max)
float scale_factor = xmax / xsize;
// if verbose flag is set, print out extracted text
// to STDOUT
if (MediaFilterManager.isVerbose)
{
System.out.println("x scale factor: " + scale_factor);
}
// now reduce x size
// and y size
xsize = xsize * scale_factor;
ysize = ysize * scale_factor;
// if verbose flag is set, print out extracted text
// to STDOUT
if (MediaFilterManager.isVerbose)
{
System.out.println("new size: " + xsize + "," + ysize);
}
}
// scale by y if needed
if (ysize > ymax)
{
float scale_factor = ymax / ysize;
// now reduce x size
// and y size
xsize = xsize * scale_factor;
ysize = ysize * scale_factor;
}
// if verbose flag is set, print details to STDOUT
if (MediaFilterManager.isVerbose)
{
System.out.println("created thumbnail size: " + xsize + ", "
+ ysize);
}
// create an image buffer for the thumbnail with the new xsize, ysize
BufferedImage thumbnail = new BufferedImage((int) xsize, (int) ysize,
BufferedImage.TYPE_INT_RGB);
// Use blurring if selected in config.
// a little blur before scaling does wonders for keeping moire in check.
if (blurring)
{
// send the buffered image off to get blurred.
buf = getBlurredInstance((BufferedImage) buf);
}
// Use high quality scaling method if selected in config.
// this has a definite performance penalty.
if (hqscaling)
{
// send the buffered image off to get an HQ downscale.
buf = getScaledInstance((BufferedImage) buf, (int) xsize, (int) ysize,
(Object) RenderingHints.VALUE_INTERPOLATION_BICUBIC, (boolean) true);
}
// now render the image into the thumbnail buffer
Graphics2D g2d = thumbnail.createGraphics();
g2d.drawImage(buf, 0, 0, (int) xsize, (int) ysize, null);
// now create an input stream for the thumbnail buffer and return it
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(thumbnail, "jpeg", baos);
// now get the array
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
return bais; // hope this gets written out before its garbage collected!
}
public String[] getInputMIMETypes()
{
return ImageIO.getReaderMIMETypes();
}
public String[] getInputDescriptions()
{
return null;
}
public String[] getInputExtensions()
{
// Temporarily disabled as JDK 1.6 only
// return ImageIO.getReaderFileSuffixes();
return null;
}
public BufferedImage getNormalizedInstance(BufferedImage buf)
{
int type = (buf.getTransparency() == Transparency.OPAQUE) ?
BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB_PRE;
int w, h;
w = buf.getWidth();
h = buf.getHeight();
BufferedImage normal = new BufferedImage(w, h, type);
Graphics2D g2d = normal.createGraphics();
g2d.drawImage(buf, 0, 0, w, h, Color.WHITE, null);
g2d.dispose();
return normal;
}
public BufferedImage getBlurredInstance(BufferedImage buf)
{
/**
* Convenience method that returns a blurred instance of the
* provided {@code BufferedImage}.
*
*/
buf = getNormalizedInstance(buf);
// kernel for blur op
float[] matrix = {
0.111f, 0.111f, 0.111f,
0.111f, 0.111f, 0.111f,
0.111f, 0.111f, 0.111f,
};
// perform the blur and return the blurred version.
BufferedImageOp blur = new ConvolveOp( new Kernel(3, 3, matrix) );
BufferedImage blurbuf = blur.filter(buf, null);
return blurbuf;
}
/**
* Convenience method that returns a scaled instance of the
* provided {@code BufferedImage}.
*
* @param buf the original image to be scaled
* @param targetWidth the desired width of the scaled instance,
* in pixels
* @param targetHeight the desired height of the scaled instance,
* in pixels
* @param hint one of the rendering hints that corresponds to
* {@code RenderingHints.KEY_INTERPOLATION} (e.g.
* {@code RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR},
* {@code RenderingHints.VALUE_INTERPOLATION_BILINEAR},
* {@code RenderingHints.VALUE_INTERPOLATION_BICUBIC})
* @param higherQuality if true, this method will use a multi-step
* scaling technique that provides higher quality than the usual
* one-step technique (only useful in downscaling cases, where
* {@code targetWidth} or {@code targetHeight} is
* smaller than the original dimensions, and generally only when
* the {@code BILINEAR} hint is specified)
* @return a scaled version of the original {@code BufferedImage}
*/
public BufferedImage getScaledInstance(BufferedImage buf,
int targetWidth,
int targetHeight,
Object hint,
boolean higherQuality)
{
int type = (buf.getTransparency() == Transparency.OPAQUE) ?
BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
BufferedImage scalebuf = (BufferedImage)buf;
int w, h;
if (higherQuality) {
// Use multi-step technique: start with original size, then
// scale down in multiple passes with drawImage()
// until the target size is reached
w = buf.getWidth();
h = buf.getHeight();
} else {
// Use one-step technique: scale directly from original
// size to target size with a single drawImage() call
w = targetWidth;
h = targetHeight;
}
do {
if (higherQuality && w > targetWidth) {
w /= 2;
if (w < targetWidth) {
w = targetWidth;
}
}
if (higherQuality && h > targetHeight) {
h /= 2;
if (h < targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(w, h, type);
Graphics2D g2d = tmp.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2d.drawImage(scalebuf, 0, 0, w, h, Color.WHITE, null);
g2d.dispose();
scalebuf = tmp;
} while (w != targetWidth || h != targetHeight);
return scalebuf;
}
}