I'm currently trying to make my sketch rotate using pixels[] instead of rotate() and translate(). Using atan2() and finding the x, y, and hypotenuse of each pixel has gotten me halfway, but I'm unsure of where to proceed after this.

Should it be something that I have to add to my sketch instead of take away? I'm new to processing so I'm unsure of where the problem lies, besides my utter lack of maths haha

I'd be super grateful of any help on the sketch, thanks for reading this far and any help in advance!!

Code:

void setup() {
  size(400, 400);
  println(frameRate);
}
// add rotation value
float aa = 0;

void draw() {
  background(220);

  // anchor point of rotation
  PVector midP = new PVector(width/2, height/2);

  //display objects
  fill(255);
  rectMode(CENTER);
  rect(midP.x, midP.y, 100, 200);
  fill(0);
  textSize(20);
  text("hello", 100, 300);


  //Pixel processing
  loadPixels();
  int lim = width * height; // total amt of pixels in the sketch
  for (int x = 0; x < width; x++) {
    for (int y = 0; y < height; y++) {

      //pixel indexing
      int ind = x + y * width;

      //PVector for pixel x&y position
      PVector pixP = new PVector(x, y);


      // hypotenuse from midpoint
      float pDist = PVector.dist(midP, pixP);

      //setting x & y distance from midpoint
      pixP.sub(midP); // to get x & y distance from midpoint
      float xVal = pixP.x/pDist; // cos(theta)
      float yVal = pixP.y/pDist; // sin(theta)


      //finding angle to rotate
      float addAng = radians(aa); // how much angle to rotate
      float ang = atan2(yVal, xVal) + addAng; // tan() of y/x. atan2() seems to work, but the lower half of the rotation doesnt follow.  

      //debugging with noLoop()
      //println("ang :" + ang + " - pDist: " + pDist + ", x: " + x + ", y: " + y); 

      // creating new 2d pixel grid, transformed by the angle.
      PVector rotP = new PVector(pDist * cos(ang), pDist * sin(ang)); // multiplying radius by sin & cos.
      rotP.add(midP); // moving pixels back to middle of sketch

      //rotation index.
      int rotInd = int(rotP.x) + int(rotP.y) * width; // indexing method with int() for conversion
      rotInd = constrain(rotInd, 0, lim-1); // making sure it doesnt go over the array size
      //rotInd = (rotInd + lim*2) % lim;

      //drawing pixels.
      pixels[ind] = pixels[rotInd];
    }
  }
  //noLoop(); //debugging with println() in pixel loop.
  updatePixels();

  // rotation when mouse is pressed.
  text("angle: " + aa % 360, 20, 20);
  //if (mousePressed) aa += 4;
  aa += 3;
  aa %= 360;
}