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* accompanied this code).
*
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package java.awt.image;
import java.awt.image.ImageConsumer;
import java.awt.image.ColorModel;
import java.util.Hashtable;
import java.awt.Rectangle;
/**
* An ImageFilter class for scaling images using the simplest algorithm.
* This class extends the basic ImageFilter Class to scale an existing
* image and provide a source for a new image containing the resampled
* image. The pixels in the source image are sampled to produce pixels
* for an image of the specified size by replicating rows and columns of
* pixels to scale up or omitting rows and columns of pixels to scale
* down.
* <p>It is meant to be used in conjunction with a FilteredImageSource
* object to produce scaled versions of existing images. Due to
* implementation dependencies, there may be differences in pixel values
* of an image filtered on different platforms.
*
* @see FilteredImageSource
* @see ImageFilter
*
* @author Jim Graham
*/
public class ReplicateScaleFilter extends ImageFilter {
/**
* The width of the source image.
*/
protected int srcWidth;
/**
* The height of the source image.
*/
protected int srcHeight;
/**
* The target width to scale the image.
*/
protected int destWidth;
/**
* The target height to scale the image.
*/
protected int destHeight;
/**
* An <code>int</code> array containing information about a
* row of pixels.
*/
protected int srcrows[];
/**
* An <code>int</code> array containing information about a
* column of pixels.
*/
protected int srccols[];
/**
* A <code>byte</code> array initialized with a size of
* {@link #destWidth} and used to deliver a row of pixel
* data to the {@link ImageConsumer}.
*/
protected Object outpixbuf;
/**
* Constructs a ReplicateScaleFilter that scales the pixels from
* its source Image as specified by the width and height parameters.
* @param width the target width to scale the image
* @param height the target height to scale the image
* @throws IllegalArgumentException if <code>width</code> equals
* zero or <code>height</code> equals zero
*/
public ReplicateScaleFilter(int width, int height) {
if (width == 0 || height == 0) {
throw new IllegalArgumentException("Width ("+width+
") and height ("+height+
") must be non-zero");
}
destWidth = width;
destHeight = height;
}
/**
* Passes along the properties from the source object after adding a
* property indicating the scale applied.
* This method invokes <code>super.setProperties</code>,
* which might result in additional properties being added.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose pixels
* are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setProperties(Hashtable<?,?> props) {
Hashtable<Object,Object> p = (Hashtable<Object,Object>)props.clone();
String key = "rescale";
String val = destWidth + "x" + destHeight;
Object o = p.get(key);
if (o != null && o instanceof String) {
val = ((String) o) + ", " + val;
}
p.put(key, val);
super.setProperties(p);
}
/**
* Override the dimensions of the source image and pass the dimensions
* of the new scaled size to the ImageConsumer.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose pixels
* are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
* @see ImageConsumer
*/
public void setDimensions(int w, int h) {
srcWidth = w;
srcHeight = h;
if (destWidth < 0) {
if (destHeight < 0) {
destWidth = srcWidth;
destHeight = srcHeight;
} else {
destWidth = srcWidth * destHeight / srcHeight;
}
} else if (destHeight < 0) {
destHeight = srcHeight * destWidth / srcWidth;
}
consumer.setDimensions(destWidth, destHeight);
}
private void calculateMaps() {
srcrows = new int[destHeight + 1];
for (int y = 0; y <= destHeight; y++) {
srcrows[y] = (2 * y * srcHeight + srcHeight) / (2 * destHeight);
}
srccols = new int[destWidth + 1];
for (int x = 0; x <= destWidth; x++) {
srccols[x] = (2 * x * srcWidth + srcWidth) / (2 * destWidth);
}
}
/**
* Choose which rows and columns of the delivered byte pixels are
* needed for the destination scaled image and pass through just
* those rows and columns that are needed, replicated as necessary.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose pixels
* are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setPixels(int x, int y, int w, int h,
ColorModel model, byte pixels[], int off,
int scansize) {
if (srcrows == null || srccols == null) {
calculateMaps();
}
int sx, sy;
int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
byte outpix[];
if (outpixbuf != null && outpixbuf instanceof byte[]) {
outpix = (byte[]) outpixbuf;
} else {
outpix = new byte[destWidth];
outpixbuf = outpix;
}
for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
int srcoff = off + scansize * (sy - y);
int dx;
for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
outpix[dx] = pixels[srcoff + sx - x];
}
if (dx > dx1) {
consumer.setPixels(dx1, dy, dx - dx1, 1,
model, outpix, dx1, destWidth);
}
}
}
/**
* Choose which rows and columns of the delivered int pixels are
* needed for the destination scaled image and pass through just
* those rows and columns that are needed, replicated as necessary.
* <p>
* Note: This method is intended to be called by the
* <code>ImageProducer</code> of the <code>Image</code> whose pixels
* are being filtered. Developers using
* this class to filter pixels from an image should avoid calling
* this method directly since that operation could interfere
* with the filtering operation.
*/
public void setPixels(int x, int y, int w, int h,
ColorModel model, int pixels[], int off,
int scansize) {
if (srcrows == null || srccols == null) {
calculateMaps();
}
int sx, sy;
int dx1 = (2 * x * destWidth + srcWidth - 1) / (2 * srcWidth);
int dy1 = (2 * y * destHeight + srcHeight - 1) / (2 * srcHeight);
int outpix[];
if (outpixbuf != null && outpixbuf instanceof int[]) {
outpix = (int[]) outpixbuf;
} else {
outpix = new int[destWidth];
outpixbuf = outpix;
}
for (int dy = dy1; (sy = srcrows[dy]) < y + h; dy++) {
int srcoff = off + scansize * (sy - y);
int dx;
for (dx = dx1; (sx = srccols[dx]) < x + w; dx++) {
outpix[dx] = pixels[srcoff + sx - x];
}
if (dx > dx1) {
consumer.setPixels(dx1, dy, dx - dx1, 1,
model, outpix, dx1, destWidth);
}
}
}
}