Hey all,

I've done my research to solve this problem but without any success.
I want my rectangle to switch its fill randomly black or white, but all I
can see is a black rectangle.

Who has a suggestion?

1. float x;
2. float y;
3. color white =color(255);
4. color black =color(0);
5. color[] colors = {            //random selects one of above colors
6.   white, black
7. };
8. color c1 = (colors(random(0,1)));
9. void setup() {
10. noStroke ();
11. size(1000, 1000);
12. smooth();
13. background (255,0,0);
14. rectMode (CENTER);
15. }
16. void draw() {
17. fill(c1); 
18. translate(mouseX, mouseY);
19. rotate((mouseX + mouseY)* 300.0);
20. rect(x, y, 30, 30);
21. }

Hellow you all,

Some of you already helped me to produce this border detection. So far so great. The "but" is following ...

Now I want to create a simple melody based on the height of the red vertex.

For the first step I started to add something like a scan bar that moves to x-direction.
But it just appeared in the right corner and doesn't move.

Who can help or knows probably a better start to work out?

1. PImage test_image;    
2. color black = color(0);
3. color white = color(255);
4. int[] positions;
5. float scan_bar;
6. void setup() {
7.   size(600,450);
8.   noLoop();
9.   positions = new int[width];
10.   test_image = loadImage("skyline.jpg");
11.    scan_bar = width;
12. } 
13. /* FIRST STEP
14. find the first black pixel from the top (y) for each column (x)*/ 
15. void findPositions() {
16.       loadPixels();
17.       for (int x=0; x<width; x++) {
18.         for (int y=0; y<height; y++) {
19.           if (y==0)
20.             { positions[x] = -1; }
21.             int index = x + y * width;
22.             color c = pixels[index];
23.               if (c == black) {
24.               positions[x] = y;
25.               print (positions[x]);
26.               print (" ");
27.               break;
28.               }
29.           }
30.         }
31.     }
32.    
33. /* SECOND STEP
34. draw the found positions with a thick red stroke*/    
35.    
36. void drawPositions() {
37.       strokeWeight(3);
38.       stroke(255, 0, 0);
39.       noFill();
40.       beginShape();
41.       for (int x=0; x<width; x++) {
42.         int y = positions[x];
43.         if (y>-1) {
44.           vertex(x, y);
45.         }
46.       }
47.       endShape();
48.     }
49. void draw() {
50. // Display the image
51. image(test_image,0,0);
52. findPositions();
53. drawPositions();
54. // Draw scan bar (doesn't work)
55. stroke(0,0,255); 
56. line(scan_bar, 0, scan_bar, height); 
57.   scan_bar = scan_bar + 1.0;
58.   if (scan_bar > width) {
59.     scan_bar = 0;
60.   }  
61. } 

Hellow!

I want to make a very easy sound programm but as a newbie there's nothing easy in its beginnings ;)

Idea_ The higher the mouse the higher the frequency. I tried following but I got this error message:
"the local variable freq may not have bee initialised".

Probably there's something wring with the order?

1. float c = 261.63;
2. float cs = 277.18;
3. float[] notas = {c, cs,};
4. void mouseMoved() {
5.   
6.   int c = 262;
7.   int cs = 277;
8.  
9.   float freq;
10.  
11.   if (mouseY<c) {
12.   freq = notas [1]; }
13.  
14.   if (mouseY<cs) {
15.   freq = notas [2]; }
16.  
17.   sine.setFreq(freq);
18. }

Hey you all,

relating to an older post I've got an new question.

How to express following with code language:
The first black pixel of an column will be saved
and after that the programm should go on scanning
the next column, saving a pixel position again and
so on and so in.

Thanks for any help.

*edit*
Would dist() probably help? My idea is that it
calculates the distance between the very first pixel
and the first black pixel. But I also don't know what's
this in code language.

1. for (int x = 0; x < source.width; x++) {
2.     for (int y = 0; y < source.height; y++ ) {
3.      
4.      int loc = x + y*source.width;
5.  
6.      int black = 0;
7.      int white = 255;  
8.    
9.     if (brightness (destination.pixels[loc]) == black) {
10.     }
11.     // save the position of the first black pixel in this column
12.     // go to the next column
13.     } 
14.     }

Hello you all,

I try to save brightness values in an 2D array, but I'm stuck.
I guess it's not that hard but I am a greener-than-grass-newbie.

This is probably something incorrect:
int[][] brightness_values = new int[cols.pixels][rows.pixels];
line 7

And here I don't know what to write in the brackets:
brightness_values[?][?] = brightness(img.pixels[i]);
line 14

Thank you for each hint!

1. size(220,165);
2. PImage img;
3. int cols = width;
4. int rows = height;
5. // Declare 2D arrays
6. int[][] myArray = new int[cols][rows];
7. int[][] brightness_values = new int[cols.pixels][rows.pixels];
8. img=loadImage("sunflower.jpg");
9. img.loadPixels();
10. // Initialize: Two nested loops allow us to visit every spot in a 2D array.  
11. // For every column I, visit every row J.
12. for (int i = 0; i < cols; i++) {
13.   for (int j = 0; j < rows; j++) {
14.     brightness_values[?][?] = brightness(img.pixels[i]);
15.   }
16. }
17. for (int i = 0; i < cols; i++) {
18.   for (int j = 0; j < rows; j++) {
19.    
20.     // Find Location of each pixel
21.     int loc = i + j*width;
22.     print (loc);
23.   }
24. }