From 3a9d32dfeebd2027f985885abcc0de8f9a63187f Mon Sep 17 00:00:00 2001
From: Jordan Eldredge <jordan@jordaneldredge.com>
Date: Wed, 2 Dec 2020 23:19:41 -0800
Subject: [PATCH] Sketch out animating .ani cursors

---
 packages/webamp/js/components/Skin.tsx | 45 +++++++++++++++++++-------
 packages/webamp/js/skinParserUtils.ts  |  8 ++---
 packages/webamp/js/types.ts            | 13 +++++++-
 3 files changed, 50 insertions(+), 16 deletions(-)

diff --git a/packages/webamp/js/components/Skin.tsx b/packages/webamp/js/components/Skin.tsx
index 0b2a1b54..2c81c394 100644
--- a/packages/webamp/js/components/Skin.tsx
+++ b/packages/webamp/js/components/Skin.tsx
@@ -5,6 +5,7 @@ import { useTypedSelector } from "../hooks";
 import * as Selectors from "../selectors";
 import { SkinImages } from "../types";
 import { createSelector } from "reselect";
+import * as Utils from "../utils";
 import Css from "./Css";
 import ClipPaths from "./ClipPaths";
 
@@ -67,19 +68,41 @@ const getCssRules = createSelector(
         );
       });
     }
+
     Object.keys(cursorSelectors).forEach((cursorName) => {
-      const cursorUrl = skinCursors[cursorName];
-      if (cursorUrl) {
+      const cursor = skinCursors[cursorName];
+      if (cursor) {
         cursorSelectors[cursorName].forEach((selector) => {
-          cssRules.push(
-            `${
-              // TODO: Fix this hack
-              // Maybe our CSS name spacing should be based on some other class/id
-              // than the one we use for defining the main div.
-              // That way it could be shared by both the player and the context menu.
-              selector.startsWith("#webamp-context-menu") ? "" : CSS_PREFIX
-            } ${selector} {cursor: url(${cursorUrl}), auto}`
-          );
+          const normalizedSelector = `${
+            // TODO: Fix this hack
+            // Maybe our CSS name spacing should be based on some other class/id
+            // than the one we use for defining the main div.
+            // That way it could be shared by both the player and the context menu.
+            selector.startsWith("#webamp-context-menu") ? "" : CSS_PREFIX
+          } ${selector}`;
+
+          switch (cursor.type) {
+            case "cur":
+              cssRules.push(
+                `${normalizedSelector} {cursor: url(${cursor.url}), auto}`
+              );
+              break;
+            case "ani": {
+              const animationName = `ani-cursor-${Utils.uniqueId()}`;
+              const frames = cursor.urls.map((url, i) => {
+                const percent = (i / (cursor.urls.length - 1)) * 100;
+                return `${percent}% { cursor: url(${url}), auto; }`;
+              });
+              const durationMs = cursor.iDispRate * 16 * frames.length;
+              const framesCss = frames.join("\n");
+              const keyframes = `@keyframes ${animationName} { ${framesCss} }`;
+              cssRules.push(keyframes);
+              cssRules.push(
+                `${normalizedSelector} { animation: ${animationName} ${durationMs}ms infinite; }`
+              );
+              break;
+            }
+          }
         });
       }
     });
diff --git a/packages/webamp/js/skinParserUtils.ts b/packages/webamp/js/skinParserUtils.ts
index ea0ac452..2efaceb8 100644
--- a/packages/webamp/js/skinParserUtils.ts
+++ b/packages/webamp/js/skinParserUtils.ts
@@ -1,5 +1,5 @@
 import JSZip from "jszip";
-import { PlaylistStyle, SkinGenExColors } from "./types";
+import { PlaylistStyle, SkinGenExColors, CursorImage } from "./types";
 import SKIN_SPRITES, { Sprite } from "./skinSprites";
 import { DEFAULT_SKIN } from "./constants";
 import * as Utils from "./utils";
@@ -129,7 +129,7 @@ const ANI_MAGIC_BASE_64 = "UklGR";
 export async function getCursorFromFilename(
   zip: JSZip,
   fileName: string
-): Promise<string | null> {
+): Promise<CursorImage | null> {
   const file = await getFileFromZip(zip, fileName, "CUR", "base64");
   if (file == null) {
     return null;
@@ -141,10 +141,10 @@ export async function getCursorFromFilename(
       throw new Error("We just read this file, how can it be null??");
     }
     const ani = parseAni(fileArr.contents as Uint8Array);
-    return ani.urls[0];
+    return { type: "ani", urls: ani.urls, iDispRate: ani.iDispRate };
   }
 
-  return `data:image/x-win-bitmap;base64,${contents}`;
+  return { type: "cur", url: `data:image/x-win-bitmap;base64,${contents}` };
 }
 
 export async function getPlaylistStyle(zip: JSZip): Promise<PlaylistStyle> {
diff --git a/packages/webamp/js/types.ts b/packages/webamp/js/types.ts
index a092f423..42225e0e 100644
--- a/packages/webamp/js/types.ts
+++ b/packages/webamp/js/types.ts
@@ -75,9 +75,20 @@ export type Band =
 
 export type Slider = Band | "preamp";
 
+export type CursorImage =
+  | {
+      type: "cur";
+      url: string;
+    }
+  | {
+      type: "ani";
+      iDispRate: number;
+      urls: string[];
+    };
+
 // TODO: Use a type to ensure these keys mirror the CURSORS constant in
 // skinParser.js
-export type Cursors = { [cursor: string]: string };
+export type Cursors = { [cursor: string]: CursorImage };
 
 export type GenLetterWidths = { [letter: string]: number };