canvas_upgrade.user.js

// ==UserScript==
// @name         Canvas tweaks
// @namespace    https://mvolfik.github.io/
// @version      0.4
// @description  Try to take over the world!
// @author       matjey
// @match        http://i.protab.cz/mazec/live/
// @downloadURL  https://gist.githubusercontent.com/mvolfik/bc928b6334edcca9f3049eb9941ea324/raw/canvas_upgrade.user.js
// @grant        GM_addStyle
// @grant        unsafeWindow
// ==/UserScript==

(function() {
    'use strict';

    GM_addStyle("canvas#canvas {height: auto !important; width: auto !important;} .live_container {height: auto !important;} footer {padding-bottom: 0.5vmin;}");
    let actual_render = render;
    console.log(actual_render);
    unsafeWindow.render = function render(map) {
        actual_render(map);
        var canvas = document.getElementById("canvas");
        var ctx = canvas.getContext("2d");
        for (let i = 0; i <= 495; i += 15) {
            ctx.beginPath();
            ctx.strokeStyle = "#00CC00";
            ctx.lineWidth = i % 75 === 0 ? 2 : 1;
            ctx.moveTo(i, 0);
            ctx.lineTo(i, 495);
            ctx.moveTo(0, i);
            ctx.lineTo(495, i);
            ctx.stroke()
        }
        ctx.fillStyle = "#00CC00";
        ctx.font = "10px monospace";
        ctx.textAlign = "center";
        ctx.textBaseline = "middle";
        for (let i = 0; i <= 32; i += 1) {
            ctx.fillText(i.toString(), i * 15 + 7.5, 8);
        }
        for (let i = 1; i <= 32; i += 1) {
            ctx.fillText(i.toString(), 7.5, i * 15 + 8);
        }
    }
})();