element-web/src/favicon.ts
2024-09-06 15:44:31 +01:00

254 lines
8.8 KiB
TypeScript

/*
Copyright 2020-2024 New Vector Ltd.
SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/
interface IParams {
// colour parameters
bgColor: string;
textColor: string;
// font styling parameters
fontFamily: string;
fontWeight: "normal" | "italic" | "bold" | "bolder" | "lighter" | number;
// positioning parameters
isUp: boolean;
isLeft: boolean;
}
const defaults: IParams = {
bgColor: "#d00",
textColor: "#fff",
fontFamily: "sans-serif", // Arial,Verdana,Times New Roman,serif,sans-serif,...
fontWeight: "bold", // normal,italic,oblique,bold,bolder,lighter,100,200,300,400,500,600,700,800,900
isUp: false,
isLeft: false,
};
// Allows dynamic rendering of a circular badge atop the loaded favicon
// supports colour, font and basic positioning parameters.
// Based upon https://github.com/ejci/favico.js/blob/master/favico.js [MIT license]
export default class Favicon {
private readonly browser = {
ff: typeof window.InstallTrigger !== "undefined",
opera: !!window.opera || navigator.userAgent.includes("Opera"),
};
private readonly params: IParams;
private readonly canvas: HTMLCanvasElement;
private readonly baseImage: HTMLImageElement;
private context!: CanvasRenderingContext2D;
private icons: HTMLLinkElement[];
private isReady = false;
// callback to run once isReady is asserted, allows for a badge to be queued for when it can be shown
private readyCb?: () => void;
public constructor(params: Partial<IParams> = {}) {
this.params = { ...defaults, ...params };
this.icons = Favicon.getIcons();
// create work canvas
this.canvas = document.createElement("canvas");
// create clone of favicon as a base
this.baseImage = document.createElement("img");
const lastIcon = this.icons[this.icons.length - 1];
if (lastIcon.hasAttribute("href")) {
this.baseImage.setAttribute("crossOrigin", "anonymous");
this.baseImage.onload = (): void => {
// get height and width of the favicon
this.canvas.height = this.baseImage.height > 0 ? this.baseImage.height : 32;
this.canvas.width = this.baseImage.width > 0 ? this.baseImage.width : 32;
this.context = this.canvas.getContext("2d")!;
this.ready();
};
this.baseImage.setAttribute("src", lastIcon.getAttribute("href")!);
} else {
this.canvas.height = this.baseImage.height = 32;
this.canvas.width = this.baseImage.width = 32;
this.context = this.canvas.getContext("2d")!;
this.ready();
}
}
private reset(): void {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
this.context.drawImage(this.baseImage, 0, 0, this.canvas.width, this.canvas.height);
}
private options(
n: number | string,
params: IParams,
): {
n: string | number;
len: number;
x: number;
y: number;
w: number;
h: number;
} {
const opt = {
n: typeof n === "number" ? Math.abs(n | 0) : n,
len: ("" + n).length,
// badge positioning constants as percentages
x: 0.4,
y: 0.4,
w: 0.6,
h: 0.6,
};
// apply positional transformations
if (params.isUp) {
if (opt.y < 0.6) {
opt.y = opt.y - 0.4;
} else {
opt.y = opt.y - 2 * opt.y + (1 - opt.w);
}
}
if (params.isLeft) {
if (opt.x < 0.6) {
opt.x = opt.x - 0.4;
} else {
opt.x = opt.x - 2 * opt.x + (1 - opt.h);
}
}
// scale the position to the canvas
opt.x = this.canvas.width * opt.x;
opt.y = this.canvas.height * opt.y;
opt.w = this.canvas.width * opt.w;
opt.h = this.canvas.height * opt.h;
return opt;
}
private circle(n: number | string, opts?: Partial<IParams>): void {
const params = { ...this.params, ...opts };
const opt = this.options(n, params);
let more = false;
if (opt.len === 2) {
opt.x = opt.x - opt.w * 0.4;
opt.w = opt.w * 1.4;
more = true;
} else if (opt.len >= 3) {
opt.x = opt.x - opt.w * 0.65;
opt.w = opt.w * 1.65;
more = true;
}
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
this.context.drawImage(this.baseImage, 0, 0, this.canvas.width, this.canvas.height);
this.context.beginPath();
const fontSize = Math.floor(opt.h * (typeof opt.n === "number" && opt.n > 99 ? 0.85 : 1)) + "px";
this.context.font = `${params.fontWeight} ${fontSize} ${params.fontFamily}`;
this.context.textAlign = "center";
if (more) {
this.context.moveTo(opt.x + opt.w / 2, opt.y);
this.context.lineTo(opt.x + opt.w - opt.h / 2, opt.y);
this.context.quadraticCurveTo(opt.x + opt.w, opt.y, opt.x + opt.w, opt.y + opt.h / 2);
this.context.lineTo(opt.x + opt.w, opt.y + opt.h - opt.h / 2);
this.context.quadraticCurveTo(opt.x + opt.w, opt.y + opt.h, opt.x + opt.w - opt.h / 2, opt.y + opt.h);
this.context.lineTo(opt.x + opt.h / 2, opt.y + opt.h);
this.context.quadraticCurveTo(opt.x, opt.y + opt.h, opt.x, opt.y + opt.h - opt.h / 2);
this.context.lineTo(opt.x, opt.y + opt.h / 2);
this.context.quadraticCurveTo(opt.x, opt.y, opt.x + opt.h / 2, opt.y);
} else {
this.context.arc(opt.x + opt.w / 2, opt.y + opt.h / 2, opt.h / 2, 0, 2 * Math.PI);
}
this.context.fillStyle = params.bgColor;
this.context.fill();
this.context.closePath();
this.context.beginPath();
this.context.stroke();
this.context.fillStyle = params.textColor;
if (typeof opt.n === "number" && opt.n > 999) {
const count = (opt.n > 9999 ? 9 : Math.floor(opt.n / 1000)) + "k+";
this.context.fillText(count, Math.floor(opt.x + opt.w / 2), Math.floor(opt.y + opt.h - opt.h * 0.2));
} else {
this.context.fillText("" + opt.n, Math.floor(opt.x + opt.w / 2), Math.floor(opt.y + opt.h - opt.h * 0.15));
}
this.context.closePath();
}
private ready(): void {
if (this.isReady) return;
this.isReady = true;
this.readyCb?.();
}
private setIcon(canvas: HTMLCanvasElement): void {
setTimeout(() => {
this.setIconSrc(canvas.toDataURL("image/png"));
}, 0);
}
private setIconSrc(url: string): void {
// if is attached to fav icon
if (this.browser.ff || this.browser.opera) {
// for FF we need to "recreate" element, attach to dom and remove old <link>
const old = this.icons[this.icons.length - 1];
const newIcon = window.document.createElement("link");
this.icons = [newIcon];
newIcon.setAttribute("rel", "icon");
newIcon.setAttribute("type", "image/png");
window.document.getElementsByTagName("head")[0].appendChild(newIcon);
newIcon.setAttribute("href", url);
old.parentNode?.removeChild(old);
} else {
this.icons.forEach((icon) => {
icon.setAttribute("href", url);
});
}
}
public badge(content: number | string, opts?: Partial<IParams>): void {
if (!this.isReady) {
this.readyCb = (): void => {
this.badge(content, opts);
};
return;
}
if (typeof content === "string" || content > 0) {
this.circle(content, opts);
} else {
this.reset();
}
this.setIcon(this.canvas);
}
private static getLinks(): HTMLLinkElement[] {
const icons: HTMLLinkElement[] = [];
const links = window.document.getElementsByTagName("head")[0].getElementsByTagName("link");
for (const link of links) {
if (link.hasAttribute("rel") && /(^|\s)icon(\s|$)/i.test(link.getAttribute("rel")!)) {
icons.push(link);
}
}
return icons;
}
private static getIcons(): HTMLLinkElement[] {
// get favicon link elements
let elms = Favicon.getLinks();
if (elms.length === 0) {
elms = [window.document.createElement("link")];
elms[0].setAttribute("rel", "icon");
window.document.getElementsByTagName("head")[0].appendChild(elms[0]);
}
elms.forEach((item) => {
item.setAttribute("type", "image/png");
});
return elms;
}
}