Coordinate Rotation

Question

I need to rotate the coordinates of the pixels of an image (or a matrix). My aim is to calculate, for each point, where it will be positioned after a rotation, and vice versa. I'm currently using this procedure:

private void setRot(int i) {
    this.rot = -i / (180.0 / Math.PI);
    this.coseno = Math.cos(rot);
    this.seno = Math.sin(rot);
}

private Point ruota(int x, int y){

    int centerY=h/2;
    int centerX=w/2;


    int j = (int) (coseno * (x-centerX) - seno * (y-centerY) + centerX);
    int i = (int) (seno * (x-centerX) + coseno * (y-centerY) + centerY);

    return new Point(j,i);
}

However, if you apply a test, using the method for each pixel, the result is not rotated about the center.

    private void esegui() {

        for(int i=0;i<w;i++)
            for(int j=0;j<h;j++){
                Point p = ruota(i,j); //ip : origina image | ip2 destination image
                ip2.putPixel(p.x, p.y, ip.getPixel(i, j));
            }
        nu.setProcessor(ip); // destination image
        nu.repaintWindow();
    }

Would someone help me make a proper rotation in one direction and in the other?

this is my Test Class:

private int getH(){ //height of destination image
    return (int) (this.h*Math.abs(coseno) + this.w*Math.abs(seno));
}
private int getW(){
    return (int) (this.plus.getHeight()*Math.abs(seno) + this.plus.getWidth()*Math.abs(coseno));
}

public Test(){ // class test
    IJ.open();
    this.plus = IJ.getImage();
    ip = plus.getProcessor();
    this.h = this.plus.getHeight(); // height of start image
    this.w = this.plus.getWidth();
    setRot(14);                     // rotation of 14°
    dHeight = this.getH();          // dimension of the target image
    dWidth = this.getW();
    System.out.println("h "+h+" gh  " + getH());
    System.out.println("w "+w+" gw  " + getW());

    // create an image target
    this.nu = NewImage.createRGBImage("rotate", getW(), getH(), 1, NewImage.FILL_BLACK);
    ip2 = nu.getProcessor();
    esegui();
    nu.setProcessor(ip2);
    nu.show();
}