1 files changed, 117 insertions, 0 deletions
diff --git a/toolkit/content/viewZoomOverlay.js b/toolkit/content/viewZoomOverlay.js
new file mode 100644
index 000000000..66e054437
--- /dev/null
+++ b/toolkit/content/viewZoomOverlay.js
@@ -0,0 +1,117 @@
+// -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/** Document Zoom Management Code
+ *
+ * To use this, you'll need to have a getBrowser() function or use the methods
+ * that accept a browser to be modified.
+ **/
+
+var ZoomManager = {
+  get _prefBranch() {
+    delete this._prefBranch;
+    return this._prefBranch = Components.classes["@mozilla.org/preferences-service;1"]
+                                        .getService(Components.interfaces.nsIPrefBranch);
+  },
+
+  get MIN() {
+    delete this.MIN;
+    return this.MIN = this._prefBranch.getIntPref("zoom.minPercent") / 100;
+  },
+
+  get MAX() {
+    delete this.MAX;
+    return this.MAX = this._prefBranch.getIntPref("zoom.maxPercent") / 100;
+  },
+
+  get useFullZoom() {
+    return this._prefBranch.getBoolPref("browser.zoom.full");
+  },
+
+  set useFullZoom(aVal) {
+    this._prefBranch.setBoolPref("browser.zoom.full", aVal);
+    return aVal;
+  },
+
+  get zoom() {
+    return this.getZoomForBrowser(getBrowser());
+  },
+
+  getZoomForBrowser: function ZoomManager_getZoomForBrowser(aBrowser) {
+    let zoom = (this.useFullZoom || aBrowser.isSyntheticDocument)
+               ? aBrowser.fullZoom : aBrowser.textZoom;
+    // Round to remove any floating-point error.
+    return Number(zoom.toFixed(2));
+  },
+
+  set zoom(aVal) {
+    this.setZoomForBrowser(getBrowser(), aVal);
+    return aVal;
+  },
+
+  setZoomForBrowser: function ZoomManager_setZoomForBrowser(aBrowser, aVal) {
+    if (aVal < this.MIN || aVal > this.MAX)
+      throw Components.results.NS_ERROR_INVALID_ARG;
+
+    if (this.useFullZoom || aBrowser.isSyntheticDocument) {
+      aBrowser.textZoom = 1;
+      aBrowser.fullZoom = aVal;
+    } else {
+      aBrowser.textZoom = aVal;
+      aBrowser.fullZoom = 1;
+    }
+  },
+
+  get zoomValues() {
+    var zoomValues = this._prefBranch.getCharPref("toolkit.zoomManager.zoomValues")
+                                     .split(",").map(parseFloat);
+    zoomValues.sort((a, b) => a - b);
+
+    while (zoomValues[0] < this.MIN)
+      zoomValues.shift();
+
+    while (zoomValues[zoomValues.length - 1] > this.MAX)
+      zoomValues.pop();
+
+    delete this.zoomValues;
+    return this.zoomValues = zoomValues;
+  },
+
+  enlarge: function ZoomManager_enlarge() {
+    var i = this.zoomValues.indexOf(this.snap(this.zoom)) + 1;
+    if (i < this.zoomValues.length)
+      this.zoom = this.zoomValues[i];
+  },
+
+  reduce: function ZoomManager_reduce() {
+    var i = this.zoomValues.indexOf(this.snap(this.zoom)) - 1;
+    if (i >= 0)
+      this.zoom = this.zoomValues[i];
+  },
+
+  reset: function ZoomManager_reset() {
+    this.zoom = 1;
+  },
+
+  toggleZoom: function ZoomManager_toggleZoom() {
+    var zoomLevel = this.zoom;
+
+    this.useFullZoom = !this.useFullZoom;
+    this.zoom = zoomLevel;
+  },
+
+  snap: function ZoomManager_snap(aVal) {
+    var values = this.zoomValues;
+    for (var i = 0; i < values.length; i++) {
+      if (values[i] >= aVal) {
+        if (i > 0 && aVal - values[i - 1] < values[i] - aVal)
+          i--;
+        return values[i];
+      }
+    }
+    return values[i - 1];
+  }
+};