[3651] in java-interest
Re: Colors of an Image
daemon@ATHENA.MIT.EDU (Jim Graham)
Tue Nov 21 12:36:04 1995
Date: Fri, 17 Nov 1995 17:46:09 -0800
From: flar@bendenweyr.Eng.Sun.COM (Jim Graham)
To: java-interest@java.Eng.Sun.COM, aleph1@dfw.net
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> How can I find the red, green, and red values for a pixel in an
> Image?
Get its ImageProducer using Image.getSource() and then register yourself
as an ImageConsumer using starProduction() and save the pixel values as
they are delivered in the setPixels() interface method. Attached is a
utility class to do this:
int[] buffer = new int[w*h];
PixelGrabber pg = new PixelGrabber(image, x, y, w, h,
buffer, 0, w);
pg.grabPixels();
// Now buffer[j * w + i] will contain the ARGB values
// for pixel (x+i, y+j) in the image.
...jim
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import java.util.Hashtable;
import java.awt.image.ImageProducer;
import java.awt.image.ImageConsumer;
import java.awt.image.ColorModel;
import java.awt.Image;
public class PixelGrabber implements ImageConsumer {
ImageProducer producer;
int dstX;
int dstY;
int dstW;
int dstH;
int[] pixelbuf;
int dstOff;
int dstScan;
private boolean grabbing;
private boolean grabbed;
public PixelGrabber(Image img, int x, int y, int w, int h,
int[] pix, int off, int scansize) {
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) {
producer = ip;
dstX = x;
dstY = y;
dstW = w;
dstH = h;
dstOff = off;
dstScan = scansize;
pixelbuf = pix;
}
public void grabPixels() throws InterruptedException {
grabPixels(0);
}
public synchronized boolean grabPixels(long ms)
throws InterruptedException
{
long end = ms + System.currentTimeMillis();
if (!grabbing) {
producer.startProduction(this);
grabbing = true;
}
while (!grabbed) {
long timeout;
if (ms == 0) {
timeout = 0;
} else {
timeout = end - System.currentTimeMillis();
if (timeout <= 0) {
break;
}
}
wait(timeout);
}
return grabbed;
}
public void setDimensions(int width, int height) {
return;
}
public void setHints(int hints) {
return;
}
public void setProperties(Hashtable props) {
return;
}
public void setColorModel(ColorModel model) {
return;
}
public void setPixels(int srcX, int srcY, int srcW, int srcH,
ColorModel model,
byte pixels[], int srcOff, int srcScan) {
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);
int dstRem = dstScan - dstW;
int srcRem = srcScan - srcW;
for (int h = srcH; h > 0; h--) {
for (int w = srcW; w > 0; w--) {
pixelbuf[dstPtr++] = model.getRGB(pixels[srcOff++] & 0xff);
}
srcOff += srcRem;
dstPtr += dstRem;
}
}
public void setPixels(int srcX, int srcY, int srcW, int srcH,
ColorModel model,
int pixels[], int srcOff, int srcScan) {
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);
int dstRem = dstScan - dstW;
int srcRem = srcScan - srcW;
for (int h = srcH; h > 0; h--) {
for (int w = srcW; w > 0; w--) {
pixelbuf[dstPtr++] = model.getRGB(pixels[srcOff++]);
}
srcOff += srcRem;
dstPtr += dstRem;
}
}
public synchronized void imageComplete(int flags) {
grabbed = true;
notifyAll();
}
}
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