Issue 3532 - Generate animation images at runtime

lib/icon.js

Index: lib/icon.js
diff --git a/lib/icon.js b/lib/icon.js
index 2011d1e23701aada50df48f3f2722514d3b3b24e..663c27046a4a50b47444397dbafb1fc30aa087a2 100644
--- a/lib/icon.js
+++ b/lib/icon.js
@@ -17,73 +17,155 @@
 
 /** @module icon */
 
-const numberOfFrames = 10;
+"use strict";
 
+const frameOpacities =  [0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,
+                         1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0,
+                         0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.0];
+const numberOfFrames = frameOpacities.length;
+const safariPlatform = require("info").platform == "safari";
+
+let stopAnimation = null;
+let animationPlaying = false;
 let whitelistedState = new ext.PageMap();
-let notificationType = null;
-let animationInterval = null;
-let animationStep = 0;
 
-function getIconPath(whitelisted)
+let loadImage =
+/**
+ * Loads an image, returning a promise

[Sebastian Noack, 2016/01/26 16:12:37]

Nit: The return value is already doumented below.

[kzar, 2016/01/26 17:10:54]

Acknowledged.

+ *
+ * @param {string} url  URL string of the image to load
+ * @return {Promise}
+ */
+exports.loadImage = function(url)
 {
-  let filename = "icons/abp-$size";
+  return new Promise((resolve, reject) => {
+    let image = new Image();
+    image.src = url;
+    image.addEventListener("load", () =>
+    {
+      resolve(image);
+    });
+    image.addEventListener("error", () => {
+      reject("Failed to load image " + url);
+    });
+  });
+};
 
-  // If the current page is whitelisted, pick an icon that indicates that
-  // Adblock Plus is disabled, however not when the notification icon has
-  // full opacity, or on Safari where icons are genrally grayscale-only.
-  if (whitelisted && animationStep < numberOfFrames && require("info").platform != "safari")
-    filename += "-whitelisted";
+function setIcon(page, notificationType, opacity, frames)
+{
+  opacity = opacity || 0;
+  let greyed = whitelistedState.get(page) && !safariPlatform && true || false;
 
-  // If the icon is currently animating to indicate a pending notification,
-  // pick the icon for the corresponing notification type and animation frame.
-  if (notificationType && animationStep > 0)
+  if (!notificationType || !frames)
   {
-    filename += "-notification-" + notificationType;
-
-    if (animationStep < numberOfFrames)
-      filename += "-" + animationStep;
+    if (notificationType && opacity > 0.5)
+      page.browserAction.setIcon("icons/abp-$size-notification-"
+                                 + notificationType + ".png");
+    else
+      page.browserAction.setIcon("icons/abp-$size" +
+                                 (greyed ? "-whitelisted" : "") + ".png");
+  }
+  else
+  {
+    chrome.browserAction.setIcon({
+      tabId: page._id,
+      imageData: frames["" + opacity + greyed]
+      });
   }
-
-  return filename + ".png";
 }
 
-function setIcon(page)
+function renderFrames(notificationType)
 {
-  page.browserAction.setIcon(getIconPath(whitelistedState.get(page)));
+  if (safariPlatform)
+    return Promise.resolve(null);
+
+  return Promise.all([
+    loadImage("icons/abp-19.png"),
+    loadImage("icons/abp-19-whitelisted.png"),
+    loadImage("icons/abp-19-notification-" + notificationType + ".png"),
+    loadImage("icons/abp-38.png"),
+    loadImage("icons/abp-38-whitelisted.png"),
+    loadImage("icons/abp-38-notification-" + notificationType + ".png"),
+  ]).then(images =>
+  {
+    let images = {
+      19: { base: [images[0], images[1]], overlay: images[2] },
+      38: { base: [images[3], images[4]], overlay: images[5] }
+    };
+
+    let frames = {};
+    let canvas = document.createElement("canvas");
+    let context = canvas.getContext("2d");
+
+    for (let size of [19, 38])
+    {
+      canvas.width = size;
+      canvas.height = size;
+      for (let whitelisted of [false, true])
+      {
+        for (let opacity of [0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1])
+        {
+          context.globalAlpha = 1;
+          context.drawImage(images[size]["base"][whitelisted | 0], 0, 0);
+          context.globalAlpha = opacity;
+          context.drawImage(images[size]["overlay"], 0, 0);
+          let frameKey = "" + opacity + whitelisted;
+          if (!(frameKey in frames))

[Sebastian Noack, 2016/01/26 16:12:37]

If you iterate over the sizes in the inner loop you don't need this check. As a
side-effect you'd also generate the key twice as often.

  data = {};
  for (let size of [19, 38])
    ...
    data[size] = context.getImageData(0, 0, size, size);
  frames["" + opacity + whitelisted] = data;

[kzar, 2016/01/26 17:10:54]

Done.

+            frames[frameKey] = {};
+          frames[frameKey][size] = context.getImageData(0, 0, size, size);
+        }
+      }
+    }
+
+    return frames;
+  });
 }
 
-function runAnimation()
+function runAnimation(notificationType)
 {
-  return setInterval(function()
+  function playAnimation(frames)
   {
-    ext.pages.query({active: true}, function(pages)
+    animationPlaying = true;
+    let animationStep = 0;
+    ext.pages.query({active: true}, pages =>
     {
-      let fadeInInterval = setInterval(function()
+      function appendActivePage(page)
       {
-        animationStep++;
-        pages.forEach(setIcon);
+        pages.push(page);
+      }
+      ext.pages.onActivated.addListener(appendActivePage);
 
-        if (animationStep < numberOfFrames)
-          return;
+      frameInterval = setInterval(() =>
+      {
+        let opacity = frameOpacities[animationStep++];
+        pages.forEach(page => {
+          if (whitelistedState.has(page))
+            setIcon(page, notificationType, opacity, frames);
+        });
 
-        setTimeout(function()
+        if (animationStep > numberOfFrames)
         {
-          let fadeOutInterval = setInterval(function()
-          {
-            animationStep--;
-            pages.forEach(setIcon);
-
-            if (animationStep > 0)
-              return;
-
-            clearInterval(fadeOutInterval);
-          }, 100);
-        },1000);
-
-        clearInterval(fadeInInterval);
+          animationStep = 0;
+          clearInterval(frameInterval);
+          animationPlaying = false;
+          ext.pages.onActivated.removeListener(appendActivePage);
+        }
       }, 100);
     });
-  }, 10000);
+  }
+
+  renderFrames(notificationType).then(frames =>
+  {
+    playAnimation(frames);
+    let animationInterval = setInterval(() => { playAnimation(frames); },
+                                        10000);
+    return () =>
+    {
+      clearInterval(frameInterval);
+      clearInterval(animationInterval);
+      animationPlaying = false;
+    };
+  });
 }
 
 /**
@@ -95,8 +177,9 @@ function runAnimation()
  */
 exports.updateIcon = function(page, whitelisted)
 {
-  page.browserAction.setIcon(getIconPath(whitelisted));
   whitelistedState.set(page, whitelisted);
+  if (!animationPlaying)
+    setIcon(page);
 };
 
 /**
@@ -106,10 +189,8 @@ exports.updateIcon = function(page, whitelisted)
  */
 exports.startIconAnimation = function(type)
 {
-  notificationType = type;
-
-  if (animationInterval == null)
-    animationInterval = runAnimation();
+  stopAnimation && stopAnimation();
+  stopAnimation = runAnimation(type);
 };
 
 /**
@@ -117,11 +198,5 @@ exports.startIconAnimation = function(type)
  */
 exports.stopIconAnimation = function()
 {
-  if (animationInterval != null)
-  {
-    clearInterval(animationInterval);
-    animationInterval = null;
-  }
-
-  notificationType  = null;
+  stopAnimation && stopAnimation();
 };