How to change the size of squares in a fixed field, based on the number of all its cells??

Question

Java

I have a square field, which I divide into cells, but the size of these cells is fixed and with a small number of rows and columns on the field, there is a lot of empty space. How to create a field with cells, the size of which will change along with the size of its rows and columns?
void repanit(){
pane.getChildren().clear();
boolean[][] b = game.getPole();
for(int i=1;i<=rows;i++)
for(int j=1;j<=cols;j++) {
Rectangle pole = new Rectangle(j*20, i*20, 20, 20);
// attempts to resize Rectangle pole = new Rectangle(j*(400/cols), i*(400/rows), 400/cols, 400/rows);
pole.setStroke(Color.BLACK);
pane.getChildren().add(pole);
}
}

Answer 1

{

for(int i=1;i<=rows;i++)
for(int j=1;j<=cols;j++) {

changed to

for(int i=0;i<=rows;i++)
for(int j=0;j<=cols;j++)

a,

Rectangle pole = new Rectangle(j*20, i*20, 20, 20);

on the

Rectangle pole = new Rectangle(j*(430/cols), i*(430/rows), 430/cols, 430/rows);

. Everything worked out, it was necessary that they did not stretch to the size of the window, but decreased when divided into larger parts.

Answer 2

Dynamically calculate? It's not entirely clear what exactly you want. Is it necessary that when the window changes, the rectangles always stretch to fit?