From 41160ff08e827e63851a3823be442d9395771ca6 Mon Sep 17 00:00:00 2001
From: Steffen Kolmer <steffen@kolmer.net>
Date: Mon, 19 Oct 2020 13:54:09 +0200
Subject: [PATCH] Render confetti the react way

---
 src/components/structures/RoomView.tsx        |  8 +++-
 src/components/views/elements/Confetti.js     | 30 ++++----------
 .../views/elements/ConfettiOverlay.tsx        | 41 +++++++++++++++++++
 3 files changed, 56 insertions(+), 23 deletions(-)
 create mode 100644 src/components/views/elements/ConfettiOverlay.tsx

diff --git a/src/components/structures/RoomView.tsx b/src/components/structures/RoomView.tsx
index f3ec8b8104..0905005cf7 100644
--- a/src/components/structures/RoomView.tsx
+++ b/src/components/structures/RoomView.tsx
@@ -73,6 +73,7 @@ import TintableSvg from "../views/elements/TintableSvg";
 import {XOR} from "../../@types/common";
 import { IThreepidInvite } from "../../stores/ThreepidInviteStore";
 import { CallState, CallType, MatrixCall } from "matrix-js-sdk/lib/webrtc/call";
+import ConfettiOverlay from "../views/elements/ConfettiOverlay";
 
 const DEBUG = false;
 let debuglog = function(msg: string) {};
@@ -693,7 +694,7 @@ export default class RoomView extends React.Component<IProps, IState> {
                 this.checkIfAlone(this.state.room);
                 break;
             case 'confetti':
-                animateConfetti(this.roomView.current.offsetWidth);
+                //TODO: animateConfetti(this.roomView.current.offsetWidth);
                 break;
             case 'post_sticker_message':
                 this.injectSticker(
@@ -853,7 +854,7 @@ export default class RoomView extends React.Component<IProps, IState> {
         this.calculateRecommendedVersion(room);
         this.updateE2EStatus(room);
         this.updatePermissions(room);
-        forceStopConfetti();
+        //TODO: forceStopConfetti();
     };
 
     private async calculateRecommendedVersion(room: Room) {
@@ -2072,6 +2073,9 @@ export default class RoomView extends React.Component<IProps, IState> {
         return (
             <RoomContext.Provider value={this.state}>
                 <main className={mainClasses} ref={this.roomView} onKeyDown={this.onReactKeyDown}>
+                    {this.roomView.current &&
+                        <ConfettiOverlay roomWidth={this.roomView.current.offsetWidth} />
+                    }
                     <ErrorBoundary>
                         <RoomHeader
                             room={this.state.room}
diff --git a/src/components/views/elements/Confetti.js b/src/components/views/elements/Confetti.js
index bef67cddcc..a4cef7e935 100644
--- a/src/components/views/elements/Confetti.js
+++ b/src/components/views/elements/Confetti.js
@@ -1,14 +1,18 @@
 /*
 MIT License
+
 Copyright (c) 2018 MathuSum Mut
+
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
+
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
+
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -89,9 +93,7 @@ const confetti = {
         }
     }
 
-    function startConfetti(roomWidth, timeout) {
-        const width = roomWidth;
-        const height = window.innerHeight;
+    function startConfetti(canvas, roomWidth, timeout) {
         window.requestAnimationFrame = (function() {
             return window.requestAnimationFrame ||
                 window.webkitRequestAnimationFrame ||
@@ -102,26 +104,12 @@ const confetti = {
                     return window.setTimeout(callback, confetti.frameInterval);
                 };
         })();
-        let canvas = document.getElementById("confetti-canvas");
-        if (canvas === null) {
-            canvas = document.createElement("canvas");
-            canvas.setAttribute("id", "confetti-canvas");
-            canvas.setAttribute("style",
-                "display:block;z-index:999999;pointer-events:none;position:fixed;top:0; right:0");
-            document.body.prepend(canvas);
-            canvas.width = width;
-            canvas.height = height;
-            window.addEventListener("resize", function() {
-                canvas.width = roomWidth;
-                canvas.height = window.innerHeight;
-            }, true);
-            context = canvas.getContext("2d");
-        } else if (context === null) {
+        if (context === null) {
             context = canvas.getContext("2d");
         }
         const count = confetti.maxCount;
         while (particles.length < count) {
-            particles.push(resetParticle({}, width, height));
+            particles.push(resetParticle({}, canvas.width, canvas.height));
         }
         streamingConfetti = true;
         runAnimation();
@@ -211,8 +199,8 @@ export function isConfettiEmoji(content) {
     return !!(hexArray.includes('1f389') || hexArray.includes('1f38a'));
 }
 
-export function animateConfetti(roomWidth) {
-    confetti.start(roomWidth, 3000);
+export function animateConfetti(canvas, roomWidth) {
+    confetti.start(canvas, roomWidth, 3000);
 }
 export function forceStopConfetti() {
     confetti.remove();
diff --git a/src/components/views/elements/ConfettiOverlay.tsx b/src/components/views/elements/ConfettiOverlay.tsx
new file mode 100644
index 0000000000..63d38d834c
--- /dev/null
+++ b/src/components/views/elements/ConfettiOverlay.tsx
@@ -0,0 +1,41 @@
+import React, {useEffect, useRef} from 'react';
+import {animateConfetti, forceStopConfetti} from './Confetti.js';
+
+export default function ConfettiOverlay({roomWidth}) {
+    const canvasRef = useRef(null);
+    // on mount
+    useEffect(() => {
+        const resize = () => {
+            const canvas = canvasRef.current;
+            canvas.height = window.innerHeight;
+        };
+        const canvas = canvasRef.current;
+        canvas.width = roomWidth;
+        canvas.height = window.innerHeight;
+        window.addEventListener("resize", resize, true);
+        animateConfetti(canvas, roomWidth);
+        return () => {
+            window.removeEventListener("resize", resize);
+            forceStopConfetti();
+        };
+    }, []);
+    // on roomWidth change
+
+    useEffect(() => {
+        const canvas = canvasRef.current;
+        canvas.width = roomWidth;
+    }, [roomWidth]);
+    return (
+        <canvas
+            ref={canvasRef}
+            style={{
+                display: "block",
+                zIndex: 999999,
+                pointerEvents: "none",
+                position: "fixed",
+                top: 0,
+                right: 0,
+            }}
+        />
+    )
+}
\ No newline at end of file