For loop matrix index

Processing Coding Questions
7

A simple package is carried out on your basis, so that four arrangements can be quickly formed.
Thank you for the algorithm provided!

int total;
float itemSize;

void setup() {
  size(800, 800); 
  pixelDensity(2);
  smooth();
  rectMode(CENTER);

  total = 4;
  itemSize = width/total;
}

void draw() {
  clear();
  drawGrid("lt");
}


// 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 == "lt" || str == "rt") {
      r1 = r;
    } else if (str == "ld" || str == "rd") {
      r1 = total - r - 1;
    }

    for (int c = 0; c < total; c++) {
      if (str == "lt" || str == "ld") {
        c1 = c;
      } else if (str == "rt" || str == "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);
      textSize(40);
      text(v, x, y);
    }
  }
}

Frame 13
Frame 131600×600 14.8 KB

algorithm by: @quark For loop matrix index - #3 by quark