März 5, 2012

PImage img;
int w, h;

void setup() {
 w = 50;
 h = 50;
 size(800, 600);
 img = loadImage("ducks.jpg");
}

void draw() {
 background(0);
 image(img, 0, 0);
 fill(getAverageColor(img, mouseX, mouseY, w, h));
 rect(mouseX, mouseY, w, h);
 //img.updatePixels();
}

color getAverageColor(PImage img, int posX, int posY, int w, int h) {
 float rA, gA, bA, r, g, b;
 rA=0;
 gA=0;
 bA=0;
 float rangeH, rangeW;

rangeH=posY+h;
 if (rangeH >height)
 rangeH = height;
 rangeW=posX+w;
 if (rangeW >width)
 rangeW = width;

for (int y = posY; y < rangeH; y++ ) {
 for (int x = posX; x < rangeW; x++ ) {
 int loc = x + y*width;
 r = red(img.pixels [loc]);
 g = green(img.pixels[loc]);
 b = blue(img.pixels[loc]);

rA+=r;
 gA+=g;
 bA+=b;
 }
 }
 rA=rA/(w*h);
 gA=gA/(w*h);
 bA=bA/(w*h);

return color(rA, gA, bA);
}