For example, pick some point on the screen, I'll call it A. Pick another point on the screen, I'll call it B, and B is defined as some distance from A (a radius distance). To make things easier, say that B is exactly above A so that B.x == A.x and B.y < A.y (because decreasing y values in Processing means up). I'll pick an arbitrary radius just to give it a number, say 10. Another point defined as being a distance (more or less due to pixel rounding) of 10 from A could be C. C would be the next point that is a part of the circle going clockwise (relative to B). You would have to do some math to make sure C has integer values for C.x and C.y, but basically it would be slightly to the right and / or down from B. Do whatever color comparisons you want between B and C. If the comparison returns the result that C should inherit some color from B, then you continue the process with another point D. D would also be a distance of 10 from A but further clockwise relative to B or C. You would do the test again to see if D inherits some color from C and so on.

To make it more interesting, you can randomize the radius distance so that it is not always 10. If you study curve programatic representations then you might be able to generalize this process to make curves that are not arcs, but that would be much more complicated.

Edit: Picking clockwise was also arbitrary, you could also randomly pick counter-clockwise and it would work, but then C would be to the left / down from B. Additionally, if you get this working well, B would not need to be absolutely above A, it could be anywhere on the circle some distance from A.

One last question though, this is the code I'm using at the mo:

2. int mode = 0;
3. 
   
4. //Pixel Sorting - Cat Ba Color/Noise
5. 
   
6. int threshold;
7. 
   
8. int loops = 1;
9. 
   
10. PImage img;
11. String imgFileName = "dashboard";
12. String fileType = "jpeg";
13. 
    
14. boolean saved = false;
15. 
    
16. void setup() {
17.   img = loadImage(imgFileName+"."+fileType);
18.   size(img.width, img.height);
19.   frameRate(12);
20.   image(img, 0, 0);
21. }
22. 
    
23. void draw(){
24.   img.loadPixels();
25.     for (int k=width; k<width*height-width; k++){
26.       if (threshold < 200) {
27.         if (brightness(img.pixels[k]) > threshold){
28.           img.pixels[k-1] = color(
29.           int(red(img.pixels[k-width])),
30.           int(green(img.pixels[k-width])),
31.           int(blue(img.pixels[k-width])));
32.         } else {
33.           img.pixels[k-width] = color(
34.           int(red(img.pixels[k+1])),
35.           int(green(img.pixels[k+1])),
36.           int(blue(img.pixels[k+1])));
37.         }
38.         threshold = threshold+1;
39.       } else {
40.         threshold = 0;
41.       }
42.       image(img,0,0);
43.   if(!saved && frameCount >= loops) {
44.     saveFrame(imgFileName+"_"+mode+".png");
45.     saved = true;
46.     println("DONE"+frameCount);
47.     System.exit(0);
48.   }
49. 
    
50.     }
51.   img.updatePixels();
52.   image(img,0,0);
53. }
54.   

It worked well until I added the chunk to save the image. So far it's only 'sorting' for one frame. I need a lot more than that to achieve anything visually noticeable. Any idea what I'd change?

Cheers again, 

Sam

Sam

2. int mode = 0;
3. 
   
4. //Pixel Sorting - Cat Ba Color/Noise
5. 
   
6. int threshold;
7. 
   
8. int loops = 1;
9. 
   
10. PImage img;
11. String imgFileName = "dashboard";
12. String fileType = "jpeg";
13. 
    
14. boolean saved = false;
15. 
    
16. void setup() {
17.   img = loadImage(imgFileName+"."+fileType);
18.   size(img.width, img.height);
19.   frameRate(12);
20.   image(img, 0, 0);
21. }
22. 
    
23. void draw() {
24.   img.loadPixels();
25.   for (int k=width; k<width*height-width; k++) {
26.     if (threshold < 200) {
27.       if (brightness(img.pixels[k]) > threshold) {
28.         img.pixels[k-1] = color(
29.         int(red(img.pixels[k-width])), 
30.         int(green(img.pixels[k-width])), 
31.         int(blue(img.pixels[k-width])));
32.       } 
33.       else {
34.         img.pixels[k-width] = color(
35.         int(red(img.pixels[k+1])), 
36.         int(green(img.pixels[k+1])), 
37.         int(blue(img.pixels[k+1])));
38.       }
39.       threshold = threshold+1;
40.     } 
41.     else {
42.       threshold = 0;
43.     }
44.     image(img, 0, 0);
45.     if (!saved && frameCount >= loops)
46.     }
47.     img.updatePixels();
48.   image(img, 0, 0);
49.   {
50.     saveFrame(imgFileName+"_"+mode+".png");
51.     saved = true;
52.     println("DONE"+frameCount);
53.     System.exit(0);
54.   }
55. }

When trying to run, the '}' at 46 is an 'unexpected token'. Deleting it results in the pairings being odd. I know these are really simple problems, but this is a pretty steep learning curve. Thanks a lot for your help.

What parameter defines how long it proceses for? Like, how extreme the effect is when finished? So I could change it to be shorter or longer... if possible.

2. //Pixel Sorting - Cat Ba Color/Noise
3. int threshold;
4. String url;
5. PImage img;
6. 
   
7. void setup(){
8.   img=loadImage("Screen Shot 2013-02-17 at 13.44.29.png");
9.   size(img.width,img.height);
10.   frameRate(12);
11.   threshold = 135;
12. }
13. 
    
14. void draw(){
15.   img.loadPixels();
16.     for (int k=width; k<width*height-width; k++){
17.       if (threshold < 255) {
18.         if (brightness(img.pixels[k]) > threshold){
19.           img.pixels[k-1] = color(
20.           int(red(img.pixels[k-width])),
21.           int(green(img.pixels[k-width])),
22.           int(blue(img.pixels[k-width])));
23.         } else {
24.           img.pixels[k-width] = color(
25.           int(red(img.pixels[k+1])),
26.           int(green(img.pixels[k+1])),
27.           int(blue(img.pixels[k+1])));
28.         }
29.         threshold = threshold+1;
30.       } else {
31.         threshold = 0;
32.       }
33.     }
34.   img.updatePixels();
35.   image(img,0,0);
36. }

Would there be a way to make it save the whole image on click for example? I'd like to be able to save the whole image at any point, even if it is bigger than the srceen (by screen capturing). Is it possible?

Thanks again for all you're help, I'm actually learning!