Rectangular Grid Using Google Apps Script in Google Slides

So, I asked ChatGPT to create a rectangular grid using Google Apps Script within Google Slides. Here are the parameters I gave it: The grid has 5 columns and 4 rows, with each rectangle being no more than 20% of the width of the grid, which is 1880px wide. The rectangles are separated by 20px margins and the slide itself has 20px margins on the outside. It sort of worked, but I had to adjust the width and height in the script because the rectangles went beyond the width and height of the 1920 x 1080 slide. Also, when I adjust the margin and number of columns, it doesn't fit exactly like I want it to. Here's the code below that it gave me...

function createGrid() {
  var slideWidth = 1440;
  var slideHeight = 810;
  var margin = 20;
  var numRows = 4;
  var numColumns = 6;
  var maxRectWidth = slideWidth * 0.2; // Each rectangle is no more than 20% of the width of the grid
  var rectWidth = Math.min((slideWidth - margin * 2 - margin * (numColumns - 1)) / numColumns, maxRectWidth);
  var rectHeight = (slideHeight - margin * 2 - margin * (numRows - 1)) / numRows;
  
  // Create new slide and set dimensions
  var presentation = SlidesApp.getActivePresentation();
  var slide = presentation.appendSlide();
  slide.selectAsCurrentPage();

  // Create grid of rectangles
  for (var row = 0; row < numRows; row++) {
    for (var column = 0; column < numColumns; column++) {
      var x = margin + column * (rectWidth + margin);
      var y = margin + row * (rectHeight + margin);
      var shape = slide.insertShape(SlidesApp.ShapeType.RECTANGLE, x, y, rectWidth, rectHeight);
      shape.getBorder().setTransparent();
      shape.getFill().setSolidFill('#777777');
    }
  }
}

Here's a screenshot of the grid it gave me. I had to adjust the SlideWidth and SlideHeight to get it to work.

So, I know that the math is wrong with the formula it's using in lines 7-9 of the script, but I'm not smart enough to change it so that no matter what margins I put in there, or number of columns or rows, it would fit within the 1920 x 1080 slide with 20px margins on the outside of the slide.

Would any of you know how to edit this script so that no matter what margin, or number of rows or columns I put in there, the rectangular grid would fit within a 1920 x 1080 slide with 20px margins on the outside?

Here's a link to make your own copy to view the script and its result.

Are you sure about the size of the slide? What if a different browser produces a smaller slide. Why not try this.

let presentation = SlidesApp.getActivePresentation();
let slides = presentation.getSlides();
let slide = slides[0];

let slideWidth = presentation.getPageWidth();
let slideHeight = presentation.getPageHeight();
let margin = 20;
let numRows = 5;
let numColumns = 4;
let rectWidth = (slideWidth - margin * 2 - margin * (numColumns - 1)) / numColumns;
let rectHeight = (slideHeight - margin * 2 - margin * (numRows - 1)) / numRows;

// Create grid of rectangles
for (let row = 0; row < numRows; row++) {
  for (let column = 0; column < numColumns; column++) {
    let x = margin + column * (rectWidth + margin);
    let y = margin + row * (rectHeight + margin);
    let shape = slide.insertShape(SlidesApp.ShapeType.RECTANGLE, x, y, rectWidth, rectHeight);
    shape.getBorder().setTransparent();
    shape.getFill().setSolidFill('#777777');
  }
}