1 files changed, 75 insertions, 0 deletions
diff --git a/devtools/client/shared/zoom-keys.js b/devtools/client/shared/zoom-keys.js
new file mode 100644
index 0000000000..b98e1a3fbd
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+++ b/devtools/client/shared/zoom-keys.js
@@ -0,0 +1,75 @@
+/* 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/. */
+
+"use strict";
+
+const ZOOM_PREF = "devtools.toolbox.zoomValue";
+const MIN_ZOOM = 0.5;
+const MAX_ZOOM = 2;
+
+const { LocalizationHelper } = require("resource://devtools/shared/l10n.js");
+const L10N = new LocalizationHelper(
+  "devtools/client/locales/toolbox.properties"
+);
+
+/**
+ * Register generic keys to control zoom level of the given document.
+ * Used by both the toolboxes and the browser console.
+ *
+ * @param {DOMWindow}
+ *        The window on which we should listent to key strokes and modify the zoom factor.
+ * @param {KeyShortcuts}
+ *        KeyShortcuts instance where the zoom keys should be added.
+ */
+exports.register = function (window, shortcuts) {
+  const bc = BrowsingContext.getFromWindow(window);
+  let zoomValue = parseFloat(Services.prefs.getCharPref(ZOOM_PREF));
+  const zoomIn = function (event) {
+    setZoom(zoomValue + 0.1);
+    event.preventDefault();
+  };
+
+  const zoomOut = function (event) {
+    setZoom(zoomValue - 0.1);
+    event.preventDefault();
+  };
+
+  const zoomReset = function (event) {
+    setZoom(1);
+    event.preventDefault();
+  };
+
+  const setZoom = function (newValue) {
+    // cap zoom value
+    zoomValue = Math.max(newValue, MIN_ZOOM);
+    zoomValue = Math.min(zoomValue, MAX_ZOOM);
+    // Prevent the floating-point error. (e.g. 1.1 + 0.1 = 1.2000000000000002)
+    zoomValue = Math.round(zoomValue * 10) / 10;
+
+    bc.fullZoom = zoomValue;
+
+    Services.prefs.setCharPref(ZOOM_PREF, zoomValue);
+  };
+
+  // Set zoom to whatever the last setting was.
+  setZoom(zoomValue);
+
+  shortcuts.on(L10N.getStr("toolbox.zoomIn.key"), zoomIn);
+  const zoomIn2 = L10N.getStr("toolbox.zoomIn2.key");
+  if (zoomIn2) {
+    shortcuts.on(zoomIn2, zoomIn);
+  }
+
+  shortcuts.on(L10N.getStr("toolbox.zoomOut.key"), zoomOut);
+  const zoomOut2 = L10N.getStr("toolbox.zoomOut2.key");
+  if (zoomOut2) {
+    shortcuts.on(zoomOut2, zoomOut);
+  }
+
+  shortcuts.on(L10N.getStr("toolbox.zoomReset.key"), zoomReset);
+  const zoomReset2 = L10N.getStr("toolbox.zoomReset2.key");
+  if (zoomReset2) {
+    shortcuts.on(zoomReset2, zoomReset);
+  }
+};