Measure pixel distribution per color.

color_quantizer

size(16, 16);

PImage img;
colorMode(RGB, 5);
img = loadImage("gray_5.jpg");
loadPixels();
float cms = 0;

int a = 0;
int b = 0;
int c = 0;
int d = 0;
int e = 0;

//image(img, 0, 0);
background(img);
println("image pixels");
for (int i=0; i<img.width; i ++ ) {
  for (int j=0; j<img.height; j ++ ) {
    
    int loc = i + j*width;
    int col = int(red(img.pixels[loc])) + 1;
    cms = cms + col * 0.5;
    println("i: " + i + ", j: " + j + ", col: " + int(col));
    
    switch(col){
      case 1:
        a++;
        break;
      case 2:
        b++;
        break;
      case 3:
        c++;
        break;
      case 4:
        d++;
        break;
      case 5:
        e++;
        break;
    }
  }
} 

println("total cms: " + cms);

println("color 1: " + a);
println("color 2: " + b);
println("color 3: " + c);
println("color 4: " + d);
println("color 5: " + e)