hello there.
I am working on image processing in Java. I was writing a
simple application which can gray-scale an image, sharpen
it , blur it, invert its colors.
Now i've writting the following code to accomplish the following
task. I used simple java.awt.image class to write the convolution
filter, instead of using java ConvolveOp operator, to clarify the
concepts but now it gives me the error which is
"Array index out of bounds Exception" and IndexColorModel sort of
error, can someone please help me, i am posting the code with it.
listing 1
/*
* <applet code=ImageFilterDemo width=350 height=450>
* <param name=img value=vincent.jpg>
* <param name=filters value="Grayscale+Invert+Contrast+Blur+Sharpen">
* </applet>
*/
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class ImageFilterDemo extends Applet implements ActionListener {
Image img;
PlugInFilter pif;
Image fimg;
Image curImg;
LoadedImage lim;
Label lab;
Button reset;
public void init() {
setLayout(new BorderLayout());
Panel p = new Panel();
add(p, BorderLayout.SOUTH);
reset = new Button("Reset");
reset.addActionListener(this);
p.add(reset);
StringTokenizer st = new StringTokenizer(getParameter("filters"),
"+");
while(st.hasMoreTokens()) {
Button b = new Button(st.nextToken());
b.addActionListener(this);
p.add(b);
}
lab = new Label("");
add(lab, BorderLayout.NORTH);
img = getImage(getDocumentBase(), getParameter("img"));
lim = new LoadedImage(img);
add(lim, BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent ae) {
String a = "";
try {
a = (String)ae.getActionCommand();
if (a.equals("Reset")) {
lim.set(img);
lab.setText("Normal");
}
else {
pif = (PlugInFilter) Class.forName(a).newInstance();
fimg = pif.filter(this, img);
lim.set(fimg);
lab.setText("Filtered: " + a);
}
repaint();
} catch (ClassNotFoundException e) {
lab.setText(a + " not found");
lim.set(img);
repaint();
} catch (InstantiationException e) {
lab.setText("could't new " + a);
} catch (IllegalAccessException e) {
lab.setText("no access: " + a);
}
}
}
listing 2
interface PlugInFilter {
java.awt.Image filter(java.applet.Applet a, java.awt.Image in);
}
listing 3
import java.awt.*;
public class LoadedImage extends Canvas {
Image img;
public LoadedImage(Image i) {
set(i);
}
void set(Image i) {
MediaTracker mt = new MediaTracker(this);
mt.addImage(i, 0);
try {
mt.waitForAll();
} catch (InterruptedException e) { };
img = i;
repaint();
}
public void paint(Graphics g) {
if (img == null) {
g.drawString("no image", 10, 30);
} else {
g.drawImage(img, 0, 0, this);
}
}
public Dimension getPreferredSize() {
return new Dimension(img.getWidth(this), img.getHeight(this));
}
public Dimension getMinimumSize() {
return getPreferredSize();
}
}
listing 4
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
class Grayscale extends RGBImageFilter implements PlugInFilter {
public Image filter(Applet a, Image in) {
return a.createImage(new FilteredImageSource(in.getSource(), this));
}
public int filterRGB(int x, int y, int rgb) {
int r = (rgb >> 16) & 0xff;
int g = (rgb >> 8) & 0xff;
int b = rgb & 0xff;
int k = (int) (.56 * g + .33 * r + .11 * b);
return (0xff000000 | k << 16 | k << 8 | k);
}
}
listing 5
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
class Invert extends RGBImageFilter implements PlugInFilter {
public Image filter(Applet a, Image in) {
return a.createImage(new FilteredImageSource(in.getSource(), this));
}
public int filterRGB(int x, int y, int rgb) {
int r = 0xff - (rgb >> 16) & 0xff;
int g = 0xff - (rgb >> 8) & 0xff;
int b = 0xff - rgb & 0xff;
return (0xff000000 | r << 16 | g << 8 | b);
}
}
listing 6
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
public class Contrast extends RGBImageFilter implements PlugInFilter {
public Image filter(Applet a, Image in) {
return a.createImage(new FilteredImageSource(in.getSource(), this));
}
private int multclamp(int in, double factor) {
in = (int) (in * factor);
return in > 255 ? 255 : in;
}
double gain = 1.2;
private int cont(int in) {
return (in < 128) ? (int)(in/gain) : multclamp(in, gain);
}
public int filterRGB(int x, int y, int rgb) {
int r = cont((rgb >> 16) & 0xff);
int g = cont((rgb >> 8) & 0xff);
int b = cont(rgb & 0xff);
return (0xff000000 | r << 16 | g << 8 | b);
}
}
listing 7
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
abstract class Convolver implements ImageConsumer, PlugInFilter {
int width, height;
int imgpixels[], newimgpixels[];
abstract void convolve(); // filter goes here...
public Image filter(Applet a, Image in) {
in.getSource().startProduction(this);
waitForImage();
newimgpixels = new int[width*height];
try {
convolve();
} catch (Exception e) {
System.out.println("Convolver failed: " + e);
e.printStackTrace();
}
return a.createImage(
new MemoryImageSource(width, height, newimgpixels, 0, width));
}
synchronized void waitForImage() {
try { wait(); } catch (Exception e) { };
}
public void setProperties(java.util.Hashtable dummy) { }
public void setColorModel(ColorModel dummy) { }
public void setHints(int dummy) { }
public synchronized void imageComplete(int dummy) {
notifyAll();
}
public void setDimensions(int x, int y) {
width = x;
height = y;
imgpixels = new int[x*y];
}
public void setPixels(int x1, int y1, int w, int h,
ColorModel model, byte pixels[], int off, int scansize) {
int pix, x, y, x2, y2, sx, sy;
x2 = x1+w;
y2 = y1+h;
sy = off;
for(y=y1; y<y2; y++) {
sx = sy;
for(x=x1; x<x2; x++) {
pix = model.getRGB(pixels[sx++]);
if((pix & 0xff000000) == 0)
pix = 0x00ffffff;
imgpixels[y*width+x] = pix;
}
sy += scansize;
}
}
public void setPixels(int x1, int y1, int w, int h,
ColorModel model, int pixels[], int off, int scansize) {
int pix, x, y, x2, y2, sx, sy;
x2 = x1+w;
y2 = y1+h;
sy = off;
for(y=y1; y<y2; y++) {
sx = sy;
for(x=x1; x<x2; x++) {
pix = model.getRGB(pixels[sx++]);
if((pix & 0xff000000) == 0)
pix = 0x00ffffff;
imgpixels[y*width+x] = pix;
}
sy += scansize;
}
}
}
listing 8
public class Blur extends Convolver {
public void convolve() {
for(int y=1; y<height-1; y++) {
for(int x=1; x<width-1; x++) {
int rs = 0;
int gs = 0;
int bs = 0;
for(int k=-1; k<=1; k++) {
for(int j=-1; j<=1; j++) {
int rgb = imgpixels[(y+k)*width+x+j];
int r = (rgb >> 16) & 0xff;
int g = (rgb >> 8) & 0xff;
int b = rgb & 0xff;
rs += r;
gs += g;
bs += b;
}
}
rs /= 9;
gs /= 9;
bs /= 9;
newimgpixels[y*width+x] = (0xff000000 |
rs << 16 | gs << 8 | bs);
}
}
}
}
listing 9
public class Sharpen extends Convolver {
private final int clamp(int c) {
return (c > 255 ? 255 : (c < 0 ? 0 : c));
}
public void convolve() {
int r0=0, g0=0, b0=0;
for(int y=1; y<height-1; y++) {
for(int x=1; x<width-1; x++) {
int rs = 0;
int gs = 0;
int bs = 0;
for(int k=-1; k<=1; k++) {
for(int j=-1; j<=1; j++) {
int rgb = imgpixels[(y+k)*width+x+j];
int r = (rgb >> 16) & 0xff;
int g = (rgb >> 8) & 0xff;
int b = rgb & 0xff;
if (j == 0 && k == 0) {
r0 = r;
g0 = g;
b0 = b;
} else {
rs += r;
gs += g;
bs += b;
}
}
}
rs >>= 3;
gs >>= 3;
bs >>= 3;
newimgpixels[y*width+x] = (0xff000000 |
clamp(r0+r0-rs) << 16 |
clamp(g0+g0-gs) << 8 |
clamp(b0+b0-bs));
}
}
}
}
The error is coming in the Convolver class, please help me
out with it. I would be obliged.
Regards,
Jules
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