For loop matrix index

Learned something new again, many thanks :slight_smile:
Processing String_equals

String a = new String("abc");
String b = new String("abc");

println(b.equals(a));
// retuen true
println(a == b);
// retuen false

I have adjusted the code:

int total;
float itemSize;

void setup() {
  size(800, 800); 
  pixelDensity(2);
  smooth();
  rectMode(CENTER);
  textAlign(CENTER, CENTER);
  textSize(60);
  total = 4;
  itemSize = width/total;
}

void draw() {
  clear();
  //drawGrid("lt");
  //drawGrid("rt");
  //drawGrid("ld");
  drawGrid("rd");
}


// lt -> left top
// rt -> right top
// ld -> left down
// rd -> right down
void drawGrid(String str) {
  int r1 = 0;
  int c1 = 0;
  for (int r = 0; r < total; r++) {
    if (str.equals("lt") || str.equals("rt")) {
      r1 = r;
    } else if (str.equals("ld")|| str.equals("rd")) {
      r1 = total - r - 1;
    }

    for (int c = 0; c < total; c++) {
      if (str.equals("lt")|| str.equals("ld")) {
        c1 = c;
      } else if (str.equals("rt")|| str.equals("rd")) {
        c1 = total-c-1;
      }
      int v = 1 + c1 + r1 * total;
      float x = (c + 0.5) * itemSize;
      float y = (r + 0.5) * itemSize;
      fill(-1);
      square(x, y, itemSize * 0.8);
      fill(0);
      text(v, x, y);
    }
  }
}