https://regiony.eu/cykloatlas/assets/leaf/L.TileGrid.js

1// JavaScript Document
2
3L.TileGrid = L.GridLayer.extend({
4
5
6  createTile: function (coords) {
7    const tile = document.createElement('canvas');
8    const ctx = tile.getContext('2d');
9    tile.width = tile.height = 256;
10    ctx.clearRect(0, 0, 256, 256);
11
12    var txt = coords.x + ' / ' + coords.y + ', zoom: ' + coords.z
13    var metrics = ctx.measureText(txt);
14    var w = metrics.width;
15
16    ctx.fillStyle = 'rgba(250,250,250, 0.7)';
17    ctx.fillRect(0, 0, w + 24, 16);
18
19    ctx.font = '12px Arial';
20    ctx.fillStyle = 'blue';
21    ctx.fillText(txt, 8, 12);
22
23    ctx.strokeStyle = 'red';
24    ctx.lineWidth = 1;
25
26    ctx.beginPath();
27    ctx.moveTo(0, 0);
28    ctx.lineTo(255, 0);
29    ctx.lineTo(255, 255);
30    //			ctx.lineTo(0, 255);
31    //			ctx.closePath();
32    ctx.stroke();
33
34    return tile;
35  },
36
37
38});
39
40L.tilegrid = function (options) {
41  return new L.TileGrid(options);
42};