Ha!  This seemed simple enough in theory but as a absolute beginner to programming this is turning out to be rather difficult.

I'm trying rearrange the pixels of an image based on color with a few things in mind.
1) Preserve the x position of the pixel
2) Push the y position of the pixel based on it's color value
     (red pixels stay where they are but as they approach blue they go down)

I started off with this simple script and was hoping to just modify it but as a newbie- I'm lost!
How can I accomplish what I'm after?  What should I look into?

1. PImage img;
2. void setup() {
3.   size(640, 480);
4. img = loadImage("Gradient_teapot.jpg");
5. }
6. void draw() {
7.   size(640, 480);
8.   background(0);
9.   loadPixels(); 
10.   for (int y = 0; y<height; y+=1 ) {
11.     for (int x = 0; x<width; x+=1) {
12.       int loc = x + y*img.width;
13.       float r = red (img.pixels[loc]);
14.       float b = blue (img.pixels[loc]);
15.     pushMatrix();
16.     translate(x,y);
17.       stroke(r,b);
18.       if (r > 1 && r < 255) {
19.         line(0,0,0,0);
20.       }
21.       if (b > 1 && b < 255) {
22.         line(0,240,0,0);
23.       }
24.     popMatrix();
25.      
26.     }
27.   }
28. println("done");
29. noLoop();
30. }

Thanks!