for (int i=0; i<iw*ih; i++) {
int p = pixels[i];
int r = 0xff & (p >> 16);
int g = 0xff & (p >> 8);
int b = 0xff & (p);
int y = (int) (.33 * r + .56 * g + .11 * b);
hist[y]++;
}
for (int i=0; i<256; i++) {
if (hist[i] > max_hist)
max_hist = hist[i];
}
}
public void update() {}
public void paint(Graphics g) {
g.drawImage(img, 0, 0, null);
int x = (w - 256) / 2;
int lasty = h - h * hist[0] / max_hist;
for (int i=0; i<256; i++, x++) {
int y = h - h * hist[i] / max_hist;
g.setColor(new Color(i, i, i));
g.fillRect(x, y, 1, h);
g.setColor(Color.red);
g.drawLine(x-1,lasty,x,y);
lasty = y;
}
}
}
Figure 25-5 shows the image and histogram for a famous Vermeer painting.
FIGURE 25-5
Sample output
from HistoGrab
Search WWH :
