File	Doc	Category	Size	Date	Package
PixelGrabber.java	API Doc	Java SE 5 API	22000	Fri Aug 26 14:56:54 BST 2005	java.awt.image

PixelGrabber

• java.lang.Object

public void handlesinglepixel(int x, int y, int pixel) {
int alpha = (pixel >> 24) & 0xff;
int red = (pixel >> 16) & 0xff;
int green = (pixel >> 8) & 0xff;
int blue = (pixel ) & 0xff;
// Deal with the pixel as necessary...
}

public void handlepixels(Image img, int x, int y, int w, int h) {
int[] pixels = new int[w * h];
PixelGrabber pg = new PixelGrabber(img, x, y, w, h, pixels, 0, w);
try {
pg.grabPixels();
} catch (InterruptedException e) {
System.err.println("interrupted waiting for pixels!");
return;
}
if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
System.err.println("image fetch aborted or errored");
return;
}
for (int j = 0; j < h; j++) {
for (int i = 0; i < w; i++) {
handlesinglepixel(x+i, y+j, pixels[j * w + i]);
}
}
}

Fields Summary
ImageProducer	producer
int	dstX
int	dstY
int	dstW
int	dstH
ColorModel	imageModel
byte[]	bytePixels
int[]	intPixels
int	dstOff
int	dstScan
private boolean	grabbing
private int	flags
private static final int	GRABBEDBITS
private static final int	DONEBITS

Constructors Summary
public PixelGrabber(Image img, int x, int y, int w, int h, int[] pix, int off, int scansize) Create a PixelGrabber object to grab the (x, y, w, h) rectangular section of pixels from the specified image into the given array. The pixels are stored into the array in the default RGB ColorModel. The RGB data for pixel (i, j) where (i, j) is inside the rectangle (x, y, w, h) is stored in the array at pix[(j - y) * scansize + (i - x) + off]. see ColorModel#getRGBdefault param img the image to retrieve pixels from param x the x coordinate of the upper left corner of the rectangle of pixels to retrieve from the image, relative to the default (unscaled) size of the image param y the y coordinate of the upper left corner of the rectangle of pixels to retrieve from the image param w the width of the rectangle of pixels to retrieve param h the height of the rectangle of pixels to retrieve param pix the array of integers which are to be used to hold the RGB pixels retrieved from the image param off the offset into the array of where to store the first pixel param scansize the distance from one row of pixels to the next in the array this(img.getSource(), x, y, w, h, pix, off, scansize);
public PixelGrabber(ImageProducer ip, int x, int y, int w, int h, int[] pix, int off, int scansize) Create a PixelGrabber object to grab the (x, y, w, h) rectangular section of pixels from the image produced by the specified ImageProducer into the given array. The pixels are stored into the array in the default RGB ColorModel. The RGB data for pixel (i, j) where (i, j) is inside the rectangle (x, y, w, h) is stored in the array at pix[(j - y) * scansize + (i - x) + off]. param ip the ImageProducer that produces the image from which to retrieve pixels param x the x coordinate of the upper left corner of the rectangle of pixels to retrieve from the image, relative to the default (unscaled) size of the image param y the y coordinate of the upper left corner of the rectangle of pixels to retrieve from the image param w the width of the rectangle of pixels to retrieve param h the height of the rectangle of pixels to retrieve param pix the array of integers which are to be used to hold the RGB pixels retrieved from the image param off the offset into the array of where to store the first pixel param scansize the distance from one row of pixels to the next in the array see ColorModel#getRGBdefault producer = ip; dstX = x; dstY = y; dstW = w; dstH = h; dstOff = off; dstScan = scansize; intPixels = pix; imageModel = ColorModel.getRGBdefault();
public PixelGrabber(Image img, int x, int y, int w, int h, boolean forceRGB) Create a PixelGrabber object to grab the (x, y, w, h) rectangular section of pixels from the specified image. The pixels are accumulated in the original ColorModel if the same ColorModel is used for every call to setPixels, otherwise the pixels are accumulated in the default RGB ColorModel. If the forceRGB parameter is true, then the pixels will be accumulated in the default RGB ColorModel anyway. A buffer is allocated by the PixelGrabber to hold the pixels in either case. If (w < 0) or (h < 0), then they will default to the remaining width and height of the source data when that information is delivered. param img the image to retrieve the image data from param x the x coordinate of the upper left corner of the rectangle of pixels to retrieve from the image, relative to the default (unscaled) size of the image param y the y coordinate of the upper left corner of the rectangle of pixels to retrieve from the image param w the width of the rectangle of pixels to retrieve param h the height of the rectangle of pixels to retrieve param forceRGB true if the pixels should always be converted to the default RGB ColorModel producer = img.getSource(); dstX = x; dstY = y; dstW = w; dstH = h; if (forceRGB) { imageModel = ColorModel.getRGBdefault(); }

Methods Summary
public synchronized void	abortGrabbing() Request the PixelGrabber to abort the image fetch. imageComplete(IMAGEABORTED);
private void	convertToRGB() int size = dstW * dstH; int newpixels[] = new int[size]; if (bytePixels != null) { for (int i = 0; i < size; i++) { newpixels[i] = imageModel.getRGB(bytePixels[i] & 0xff); } } else if (intPixels != null) { for (int i = 0; i < size; i++) { newpixels[i] = imageModel.getRGB(intPixels[i]); } } bytePixels = null; intPixels = newpixels; dstScan = dstW; dstOff = 0; imageModel = ColorModel.getRGBdefault();
public synchronized java.awt.image.ColorModel	getColorModel() Get the ColorModel for the pixels stored in the array. If the PixelGrabber was constructed with an explicit pixel buffer then this method will always return the default RGB ColorModel, otherwise it may return null until the ColorModel used by the ImageProducer is known. Since the PixelGrabber may fall back on accumulating the data in the default RGB ColorModel at any time if the source image uses more than one ColorModel to deliver the data, the ColorModel object returned by this method may change over time until the image grab is complete and may not reflect any of the ColorModel objects that was used by the ImageProducer to deliver the pixels. return the ColorModel object used for storing the pixels see #getStatus see ColorModel#getRGBdefault see #setColorModel(ColorModel) return imageModel;
public synchronized int	getHeight() Get the height of the pixel buffer (after adjusting for image height). If no width was specified for the rectangle of pixels to grab then then this information will only be available after the image has delivered the dimensions. return the final height used for the pixel buffer or -1 if the height is not yet known see #getStatus return (dstH < 0) ? -1 : dstH;
public synchronized java.lang.Object	getPixels() Get the pixel buffer. If the PixelGrabber was not constructed with an explicit pixel buffer to hold the pixels then this method will return null until the size and format of the image data is known. Since the PixelGrabber may fall back on accumulating the data in the default RGB ColorModel at any time if the source image uses more than one ColorModel to deliver the data, the array object returned by this method may change over time until the image grab is complete. return either a byte array or an int array see #getStatus see #setPixels(int, int, int, int, ColorModel, byte[], int, int) see #setPixels(int, int, int, int, ColorModel, int[], int, int) return (bytePixels == null) ? ((Object) intPixels) : ((Object) bytePixels);
public synchronized int	getStatus() Return the status of the pixels. The ImageObserver flags representing the available pixel information are returned. return the bitwise OR of all relevant ImageObserver flags see ImageObserver return flags;
public synchronized int	getWidth() Get the width of the pixel buffer (after adjusting for image width). If no width was specified for the rectangle of pixels to grab then then this information will only be available after the image has delivered the dimensions. return the final width used for the pixel buffer or -1 if the width is not yet known see #getStatus return (dstW < 0) ? -1 : dstW;
public boolean	grabPixels() Request the Image or ImageProducer to start delivering pixels and wait for all of the pixels in the rectangle of interest to be delivered. return true if the pixels were successfully grabbed, false on abort, error or timeout exception InterruptedException Another thread has interrupted this thread. return grabPixels(0);
public synchronized boolean	grabPixels(long ms) Request the Image or ImageProducer to start delivering pixels and wait for all of the pixels in the rectangle of interest to be delivered or until the specified timeout has elapsed. This method behaves in the following ways, depending on the value of ms: If ms == 0, waits until all pixels are delivered If ms > 0, waits until all pixels are delivered as timeout expires. If ms < 0, returns true if all pixels are grabbed, false otherwise and does not wait. param ms the number of milliseconds to wait for the image pixels to arrive before timing out return true if the pixels were successfully grabbed, false on abort, error or timeout exception InterruptedException Another thread has interrupted this thread. if ((flags & DONEBITS) != 0) { return (flags & GRABBEDBITS) != 0; } long end = ms + System.currentTimeMillis(); if (!grabbing) { grabbing = true; flags &= ~(ImageObserver.ABORT); producer.startProduction(this); } while (grabbing) { long timeout; if (ms == 0) { timeout = 0; } else { timeout = end - System.currentTimeMillis(); if (timeout <= 0) { break; } } wait(timeout); } return (flags & GRABBEDBITS) != 0;
public synchronized void	imageComplete(int status) The imageComplete method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param status the status of image loading grabbing = false; switch (status) { default: case IMAGEERROR: flags |= ImageObserver.ERROR | ImageObserver.ABORT; break; case IMAGEABORTED: flags |= ImageObserver.ABORT; break; case STATICIMAGEDONE: flags |= ImageObserver.ALLBITS; break; case SINGLEFRAMEDONE: flags |= ImageObserver.FRAMEBITS; break; } producer.removeConsumer(this); notifyAll();
public void	setColorModel(java.awt.image.ColorModel model) The setColorModel method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param model the specified ColorModel see #getColorModel return;
public void	setDimensions(int width, int height) The setDimensions method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param width the width of the dimension param height the height of the dimension if (dstW < 0) { dstW = width - dstX; } if (dstH < 0) { dstH = height - dstY; } if (dstW <= 0 || dstH <= 0) { imageComplete(STATICIMAGEDONE); } else if (intPixels == null && imageModel == ColorModel.getRGBdefault()) { intPixels = new int[dstW * dstH]; dstScan = dstW; dstOff = 0; } flags |= (ImageObserver.WIDTH | ImageObserver.HEIGHT);
public void	setHints(int hints) The setHints method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param hints a set of hints used to process the pixels return;
public void	setPixels(int srcX, int srcY, int srcW, int srcH, java.awt.image.ColorModel model, byte[] pixels, int srcOff, int srcScan) The setPixels method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param srcX, srcY the coordinates of the upper-left corner of the area of pixels to be set param srcW the width of the area of pixels param srcH the height of the area of pixels param model the specified ColorModel param pixels the array of pixels param srcOff the offset into the pixels array param srcScan the distance from one row of pixels to the next in the pixels array see #getPixels if (srcY < dstY) { int diff = dstY - srcY; if (diff >= srcH) { return; } srcOff += srcScan * diff; srcY += diff; srcH -= diff; } if (srcY + srcH > dstY + dstH) { srcH = (dstY + dstH) - srcY; if (srcH <= 0) { return; } } if (srcX < dstX) { int diff = dstX - srcX; if (diff >= srcW) { return; } srcOff += diff; srcX += diff; srcW -= diff; } if (srcX + srcW > dstX + dstW) { srcW = (dstX + dstW) - srcX; if (srcW <= 0) { return; } } int dstPtr = dstOff + (srcY - dstY) * dstScan + (srcX - dstX); if (intPixels == null) { if (bytePixels == null) { bytePixels = new byte[dstW * dstH]; dstScan = dstW; dstOff = 0; imageModel = model; } else if (imageModel != model) { convertToRGB(); } if (bytePixels != null) { for (int h = srcH; h > 0; h--) { System.arraycopy(pixels, srcOff, bytePixels, dstPtr, srcW); srcOff += srcScan; dstPtr += dstScan; } } } if (intPixels != null) { int dstRem = dstScan - srcW; int srcRem = srcScan - srcW; for (int h = srcH; h > 0; h--) { for (int w = srcW; w > 0; w--) { intPixels[dstPtr++] = model.getRGB(pixels[srcOff++]&0xff); } srcOff += srcRem; dstPtr += dstRem; } } flags |= ImageObserver.SOMEBITS;
public void	setPixels(int srcX, int srcY, int srcW, int srcH, java.awt.image.ColorModel model, int[] pixels, int srcOff, int srcScan) The setPixels method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param srcX, srcY the coordinates of the upper-left corner of the area of pixels to be set param srcW the width of the area of pixels param srcH the height of the area of pixels param model the specified ColorModel param pixels the array of pixels param srcOff the offset into the pixels array param srcScan the distance from one row of pixels to the next in the pixels array see #getPixels if (srcY < dstY) { int diff = dstY - srcY; if (diff >= srcH) { return; } srcOff += srcScan * diff; srcY += diff; srcH -= diff; } if (srcY + srcH > dstY + dstH) { srcH = (dstY + dstH) - srcY; if (srcH <= 0) { return; } } if (srcX < dstX) { int diff = dstX - srcX; if (diff >= srcW) { return; } srcOff += diff; srcX += diff; srcW -= diff; } if (srcX + srcW > dstX + dstW) { srcW = (dstX + dstW) - srcX; if (srcW <= 0) { return; } } if (intPixels == null) { if (bytePixels == null) { intPixels = new int[dstW * dstH]; dstScan = dstW; dstOff = 0; imageModel = model; } else { convertToRGB(); } } int dstPtr = dstOff + (srcY - dstY) * dstScan + (srcX - dstX); if (imageModel == model) { for (int h = srcH; h > 0; h--) { System.arraycopy(pixels, srcOff, intPixels, dstPtr, srcW); srcOff += srcScan; dstPtr += dstScan; } } else { if (imageModel != ColorModel.getRGBdefault()) { convertToRGB(); } int dstRem = dstScan - srcW; int srcRem = srcScan - srcW; for (int h = srcH; h > 0; h--) { for (int w = srcW; w > 0; w--) { intPixels[dstPtr++] = model.getRGB(pixels[srcOff++]); } srcOff += srcRem; dstPtr += dstRem; } } flags |= ImageObserver.SOMEBITS;
public void	setProperties(java.util.Hashtable props) The setProperties method is part of the ImageConsumer API which this class must implement to retrieve the pixels. Note: This method is intended to be called by the ImageProducer of the Image whose pixels are being grabbed. Developers using this class to retrieve pixels from an image should avoid calling this method directly since that operation could result in problems with retrieving the requested pixels. param props the list of properties return;
public synchronized void	startGrabbing() Request the PixelGrabber to start fetching the pixels. if ((flags & DONEBITS) != 0) { return; } if (!grabbing) { grabbing = true; flags &= ~(ImageObserver.ABORT); producer.startProduction(this); }
public synchronized int	status() Returns the status of the pixels. The ImageObserver flags representing the available pixel information are returned. This method and {@link #getStatus() getStatus} have the same implementation, but getStatus is the preferred method because it conforms to the convention of naming information-retrieval methods with the form "getXXX". return the bitwise OR of all relevant ImageObserver flags see ImageObserver see #getStatus() return flags;