Java-creating discrete rainbow colors

Question

It's hard to describe what I'm trying to do. I basically want to create a discrete rainbow gradient, so for any row of the i-th number of JButtons the color gradient will look like a rainbow over them.

I did the following, but only actually creates a red gradient, followed by a green gradient, followed by a blue gradient:

Color[] c = new Color[i];
    for(int n = 0; n < i; n++) {
        if(n < i/3) {
            c[n] = new Color(255, 255/(n+1), 255/(n+1));
        } else if(n < 2*i/3) {
            c[n] = new Color(255/(n-(i/3)), 255, 255/(n-(i/3)));
        } else {
            c[n] = new Color(255/(n+1), 255/(n+1), 255);
        }
    }

Any idea how I can get some kind of rainbow effect?

thank

EDIT:

The Sine function is used, which seems to work a little better, but not sure how to determine it, so I get one “rainbow wave” in the area I want:

for(int n = 0; n < i; n++) {
        c[n] = new Color((int)(Math.sin(n) * 127 + 128), (int)(Math.sin(n + Math.PI/2) * 127 + 128), (int)(Math.sin(n + Math.PI) * 127 + 128));
    }

Answer 1

, - .

, :

Color(  0, 255,   0)

, :

Color( 51, 255,   0)
Color(102, 255,   0)
Color(153, 255,   0)
Color(204, 255,   0)
Color(255, 255,   0)

, :

Color(255, 204,   0)
Color(255, 153,   0)
Color(255, 102,   0)
Color(255,  51,   0)
Color(255,   0,   0)

, :

Color(255,   0,  51)
Color(255,   0, 102)
Color(255,   0, 153)
Color(255,   0, 204)
Color(255,   0, 255)

, :

Color(204,   0, 255)
Color(153,   0, 255)
Color(102,   0, 255)
Color( 51,   0, 255)
Color(  0,   0, 255)

, :

Color(  0,  51, 255)
Color(  0, 102, 255)
Color(  0, 153, 255)
Color(  0, 204, 255)
Color(  0, 255, 255)

, , , :

Color(  0, 255, 204)
Color(  0, 255, 153)
Color(  0, 255, 102)
Color(  0, 255,  51)
Color(  0, 255,   0)

, , .

:

List<Color> colors = new ArrayList<Color>();
for (int r=0; r<100; r++) colors.add(new Color(r*255/100,       255,         0));
for (int g=100; g>0; g--) colors.add(new Color(      255, g*255/100,         0));
for (int b=0; b<100; b++) colors.add(new Color(      255,         0, b*255/100));
for (int r=100; r>0; r--) colors.add(new Color(r*255/100,         0,       255));
for (int g=0; g<100; g++) colors.add(new Color(        0, g*255/100,       255));
for (int b=100; b>0; b--) colors.add(new Color(        0,       255, b*255/100));
                          colors.add(new Color(        0,       255,         0));

100 - , .

, :

Color[] c = colors.toArray(new Color[colors.size()]);

: , . , , . , -, .

PS: , , , , , . , , .