http://processing.org/reference/get_.html

get(x, y) gets the rgb value at x, y. returns the pixel value

red(), green() and blue() will get the components from the pixel value.

write something, post it here and people will debug it...

thx... the part of getting RGB is now working (but this wasn't the big problem). I still having troubles with the understanding how to make coordinates. (a small tip for me ??? )

 

1. int x = 200;
   int y = 200;
2. void setup() {
     size(400,400);
     PImage myImage = loadImage("6_3.jpg");
   image(myImage, 0, 0);
3. 
   // GET COLOR
   int r = int(red(get(x, y)));
   int g = int(green(get(x, y)));
   int b = int(blue(get(x, y)));
4. // Print RGB
   println(r + ", " + g + ", " + b);
   }

You're having trouble with the coordinate system... does the Coordinate System and Shapes Tutorial help?

It sounds like you're used to being able to move a point around the screen and do things with it (I don't know a shorter way of putting this)... if I'm correct, does this come from ActionScript? Anyway... Processing uses... (I'm making up terminology here) a definite coordinate system... so you have to specify the exact coordinates, not coordinates relative to other coordinates.

I would recommend creating a function that prints out the color of the pixel selected with x and y, then you can change those positions and call the function again...

You might also want to look into using a for loop or two!

I'm making small steps :) Okay, I'm able to calculate the coordinates, but know how to combine them??

Combination should look like that: (reason: see image)
Column0= Row0, Row2, Row 4, Row6,...
Column1= Row1, Row3, Row5, Row7,...
Column2= Row0, Row2, Row 4, Row6,...

so at the end it should be

Column0, Row0   RGB
Column0, Row2   RGB
Column0, Row4   RGB
Column1, Row1   RGB
Column1, Row3   RGB

 

1. // Image Variable
   int imageX = 500;
   int imageY = 500;
2. // Space Variable
   int spacecolumn = 50;
   int spacerow = 50;
   float rowshift = sqrt(sq(spacerow*2)-sq(spacerow))/2;
3. // Array Variable
   float[] column = new float[imageX/spacecolumn];
   float[] row = new float[imageY/spacerow];
4. // Color Variable
   float[] re = new float[10];
5. 
   void setup() {
   // load image
     size(imageX,imageY);
     PImage myimage = loadImage("6_3.jpg");
   image(myimage, 0, 0);
6. // X cordinates
   for (int i = 0; i < imageX/spacecolumn; i = i + 1) {
      column[i] =  spacecolumn/2+spacecolumn/2*i;
   }
7. // Y cordinates
   row[0] = spacerow/2;
   for (int j = 1; j < imageY/spacerow; j = j + 1) {
      row[j] =  spacerow/2+rowshift*j;
   }
8. //test rgb
   for (float j = 0; j < 10; j = j+1) {
     re[j] = float(red(get(row[j], 30)));
   }
9. 
   int x = 200;
   int y = 200;
10. // get color
    int r = int(red(get(x, y)));
    int g = int(green(get(x, y)));
    int b = int(blue(get(x, y)));
11. // show data
    println(r + ", " + g + ", " + b);
    println(row);
    }

just one more question: I tried to get the rgb values, but this won't work with arrays, or?

 

for (int i = 0; i < 10; i = i+1) {
  re[i] = int(red(get(row[i], 30)));
}

" this won't work with arrays"
Aah, the dreaded "it doesn't work"!
Do you have an error message? Unexpected behavior?
There is no reason it shouldn't work with arrays...

// Color Variable
int[] re = new int[10];

 

for (int i = 0; i < 10; i = i+1) {
  re[i] = int(red(get(row[i], 30)));
}

 

Don't tell me, tell my computer:
Error: The method get(int,int) in the type PApplet is not applicable for the arguments (float, int)

 

This error message means:

Yes, I wasn't too sure (lazy about checking) as most Processing functions accept float parameters as well as int.
The message is quite explicit: the problem isn't about the array, but about the type of the parameter.
Try: re[i] = int(red(get(int(row[i]), 30)));
I haven't checked if it makes sense... Might be simpler to declare row as an array of ints, perhaps.

allonestr: Thx for information, I updated the code. I already calculated the coordinates (see image)

allonestr. & PhiLho: The calculation of the coordinates gives me more headache.

1. Somehow I must combine them to get the RGB values...

Row 0 / Column 0	Row 0 / Column 2	Row 0 / Column 4	Row 0 / Column 6
Row 1 / Column 1	Row 1 / Column 3	Row 1 / Column 5	Row 1 / Column 7
Row 2 / Column 0	Row 2 / Column 2	Row 2 / Column 4	Row 2 / Column 6
Row 3 / Column 1	Row 3 / Column 3	Row 3 / Column 5	Row 3 / Column 7

2. because I needed decimals I used float. Now I change to

//test rgb
for (float j = 0; j < 10; j = j+1) {
  re[j] = float(red(get(row[j], 30)));
}

now I have "cannot convert from float to int", but I have no int

You did the reverse, you changed an int to a float, which doesn't make much sense there, and isn't usable as array index.
Just stick at the line I gave.

Here's some code to start the gird. I haven't dealt with the offset on the odd numbered rows. The command modulo will help you do this.

Philho: sorry: "syntax error, maybe a missing right parenthesis?"

allonestr.: thx, but these circles are not placeshifted (like the image you and I posted).

I finshed the circles coordinate, now I'm checking the modulo code. Meantime here is my new code... it realy looks professional :)

 

1. // Image Variable
   int imageX = 500;
   int imageY = 500;
2. // circlesize Variable
   int circlesize = 50;
   int circlehalf = circlesize/2;
   float rowshift = sqrt(sq(circlesize*2)-sq(circlesize))/2;
3. // Array Variable
   float[] column = new float[imageX/circlesize];
   float[] row = new float[imageY/circlesize];
4. // Color Variable
   float[] re = new float[50];
   float[] gr = new float[50];
   float[] bl = new float[50];
5. 
   void setup() {
   // load image
     size(imageX,imageY);
     PImage myimage = loadImage("6_3.jpg");
   image(myimage, 0, 0);
6. // X cordinates
   for (int i = 0; i < imageX/circlesize; i++ ) {
      column[i] =  circlehalf + circlehalf * i;
   }
7. // Y cordinates
   row[0] = circlehalf;
   for (int j = 1; j < imageY/circlesize; j++) {
      row[j] =  circlehalf + rowshift * j;
   }
8. //test rgb
   for (int j = 0; j < 10; j++ ) {
     re[j] = int(red(int(get(row[j], 30)));
   }

 

ok this is realy getting frustad...I make this simpler...

I calculate the coordinates in excel and have 5 columns ( Coordinate X, Coordinate Y, Color Red, Color Green, Color Blue)The program should load the image and csv file, check the rgb and write the colors in the csv.

so let's see how to split the column and get the RGBs...