1 files changed, 153 insertions, 0 deletions
diff --git a/comm/mail/base/content/viewZoomOverlay.js b/comm/mail/base/content/viewZoomOverlay.js
new file mode 100644
index 0000000000..523386f82e
--- /dev/null
+++ b/comm/mail/base/content/viewZoomOverlay.js
@@ -0,0 +1,153 @@
+// -*- 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/. */
+
+/* globals getBrowser */
+
+/** Document Zoom Management Code
+ *
+ * Forked from M-C since we don't provide a global gBrowser variable.
+ *
+ * TODO: Move to dedicated js module - see bug 1841768.
+ */
+
+var ZoomManager = {
+  get MIN() {
+    delete this.MIN;
+    return (this.MIN = Services.prefs.getIntPref("zoom.minPercent") / 100);
+  },
+
+  get MAX() {
+    delete this.MAX;
+    return (this.MAX = Services.prefs.getIntPref("zoom.maxPercent") / 100);
+  },
+
+  get useFullZoom() {
+    return Services.prefs.getBoolPref("browser.zoom.full");
+  },
+
+  set useFullZoom(aVal) {
+    Services.prefs.setBoolPref("browser.zoom.full", aVal);
+  },
+
+  get zoom() {
+    return this.getZoomForBrowser(getBrowser());
+  },
+
+  useFullZoomForBrowser(aBrowser) {
+    return this.useFullZoom || aBrowser.isSyntheticDocument;
+  },
+
+  getFullZoomForBrowser(aBrowser) {
+    if (!this.useFullZoomForBrowser(aBrowser)) {
+      return 1.0;
+    }
+    return this.getZoomForBrowser(aBrowser);
+  },
+
+  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(getBrowser(), aVal);
+  },
+
+  setZoomForBrowser(browser, val) {
+    if (val < this.MIN || val > this.MAX) {
+      throw Components.Exception(
+        `invalid zoom value: ${val}`,
+        Cr.NS_ERROR_INVALID_ARG
+      );
+    }
+
+    let fullZoom = this.useFullZoomForBrowser(browser);
+    browser.textZoom = fullZoom ? 1 : val;
+    browser.fullZoom = fullZoom ? val : 1;
+  },
+
+  get zoomValues() {
+    var zoomValues = Services.prefs
+      .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(browser = getBrowser()) {
+    const i =
+      this.zoomValues.indexOf(this.snap(this.getZoomForBrowser(browser))) + 1;
+    if (i < this.zoomValues.length) {
+      this.setZoomForBrowser(browser, this.zoomValues[i]);
+    }
+  },
+
+  reduce(browser = getBrowser()) {
+    const i =
+      this.zoomValues.indexOf(this.snap(this.getZoomForBrowser(browser))) - 1;
+    if (i >= 0) {
+      this.setZoomForBrowser(browser, this.zoomValues[i]);
+    }
+  },
+
+  reset(browser = getBrowser()) {
+    this.setZoomForBrowser(browser, 1);
+  },
+
+  toggleZoom(browser = getBrowser()) {
+    const zoomLevel = this.getZoomForBrowser();
+
+    this.useFullZoom = !this.useFullZoom;
+    this.setZoomForBrowser(browser, zoomLevel);
+  },
+
+  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];
+  },
+
+  scrollZoomEnlarge(messagePaneBrowser) {
+    let zoom = messagePaneBrowser.fullZoom;
+    zoom += 0.1;
+    let zoomMax = Services.prefs.getIntPref("zoom.maxPercent") / 100;
+    if (zoom > zoomMax) {
+      zoom = zoomMax;
+    }
+    messagePaneBrowser.fullZoom = zoom;
+  },
+
+  scrollReduceEnlarge(messagePaneBrowser) {
+    let zoom = messagePaneBrowser.fullZoom;
+    zoom -= 0.1;
+    let zoomMin = Services.prefs.getIntPref("zoom.minPercent") / 100;
+    if (zoom < zoomMin) {
+      zoom = zoomMin;
+    }
+    messagePaneBrowser.fullZoom = zoom;
+  },
+};