1 files changed, 141 insertions, 0 deletions
diff --git a/toolkit/content/viewZoomOverlay.js b/toolkit/content/viewZoomOverlay.js
new file mode 100644
index 0000000000..36142d3d51
--- /dev/null
+++ b/toolkit/content/viewZoomOverlay.js
@@ -0,0 +1,141 @@
+// -*- 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 global gBrowser variable
+ * or use the methods that accept a browser to be modified.
+ **/
+
+var ZoomManager = {
+  set useFullZoom(aVal) {
+    Services.prefs.setBoolPref("browser.zoom.full", aVal);
+  },
+
+  get zoom() {
+    return this.getZoomForBrowser(gBrowser);
+  },
+
+  useFullZoomForBrowser: function ZoomManager_useFullZoomForBrowser(aBrowser) {
+    return this.useFullZoom || aBrowser.isSyntheticDocument;
+  },
+
+  getFullZoomForBrowser: function ZoomManager_getFullZoomForBrowser(aBrowser) {
+    if (!this.useFullZoomForBrowser(aBrowser)) {
+      return 1.0;
+    }
+    return this.getZoomForBrowser(aBrowser);
+  },
+
+  getZoomForBrowser: function ZoomManager_getZoomForBrowser(aBrowser) {
+    let zoom = this.useFullZoomForBrowser(aBrowser)
+      ? aBrowser.fullZoom
+      : aBrowser.textZoom;
+    // Round to remove any floating-point error.
+    return Number(zoom ? zoom.toFixed(2) : 1);
+  },
+
+  set zoom(aVal) {
+    this.setZoomForBrowser(gBrowser, aVal);
+  },
+
+  setZoomForBrowser: function ZoomManager_setZoomForBrowser(aBrowser, aVal) {
+    if (aVal < this.MIN || aVal > this.MAX) {
+      throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    if (this.useFullZoomForBrowser(aBrowser)) {
+      aBrowser.textZoom = 1;
+      aBrowser.fullZoom = aVal;
+    } else {
+      aBrowser.textZoom = aVal;
+      aBrowser.fullZoom = 1;
+    }
+  },
+
+  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];
+  },
+};
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  ZoomManager,
+  "MIN",
+  "zoom.minPercent",
+  30,
+  null,
+  v => v / 100
+);
+XPCOMUtils.defineLazyPreferenceGetter(
+  ZoomManager,
+  "MAX",
+  "zoom.maxPercent",
+  500,
+  null,
+  v => v / 100
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  ZoomManager,
+  "zoomValues",
+  "toolkit.zoomManager.zoomValues",
+  ".3,.5,.67,.8,.9,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3,4,5",
+  null,
+  zoomValues => {
+    zoomValues = 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();
+    }
+
+    return zoomValues;
+  }
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  ZoomManager,
+  "useFullZoom",
+  "browser.zoom.full"
+);