Add support for specifying a favicon generation function in branding extension. (#52)

* Add branding extensions

* prettier

* Add favicon function extension.

* lint

* Update docs and types.

Author: Half-Shot

src/lifecycles/BrandingExtensions.ts

@@ -29,6 +29,19 @@ export interface AppTitleInRoom extends AppTitleBase {
     roomId: string;
 }
 
+export interface GetFaviconParameters {
+    // colour parameters
+    bgColor: string;
+    textColor: string;
+    // font styling parameters
+    fontFamily: string;
+    fontWeight: "normal" | "italic" | "bold" | "bolder" | "lighter" | number;
+
+    // positioning parameters
+    isUp: boolean;
+    isLeft: boolean;
+}
+
 export type AppTitleContext = AppTitleBase | AppTitleInRoom;
 
 export interface ProvideBrandingExtensions {
@@ -38,10 +51,25 @@ export interface ProvideBrandingExtensions {
      * @returns A string to be used for the full title, or null to use the default title.
      */
     getAppTitle(context: AppTitleContext): string | null;
+    /**
+     * Called when the app needs to generate the basic app favicon.
+     * @returns A string URL for the icon, or null if no new icon should be generated.
+     */
+    getFaviconSrc(): PromiseLike<string | null>;
+    /**
+     * Called when the app needs to generate a new "badge" favicon.
+     * @param content The content inside the "badge".
+     * @param opts Extra parameters for the badge.
+     * @returns A string URL for the icon, or null if no new icon should be generated.
+     */
+    getFaviconSrc(content: number | string, opts: GetFaviconParameters): PromiseLike<string | null>;
 }
 
 export abstract class BrandingExtensionsBase implements ProvideBrandingExtensions {
     public getAppTitle(context: AppTitleContext): string | null {
         return null;
     }
+    public async getFaviconSrc(content?: number | string, opts?: GetFaviconParameters): Promise<string | null> {
+        return null;
+    }
 }