From 38fa2d78da5bb4da846b8ceb2c8c4643b744d690 Mon Sep 17 00:00:00 2001
From: Daniel Imms <tyriar@tyriar.com>
Date: Wed, 3 Aug 2016 13:00:07 -0700
Subject: [PATCH] Support DOMMouseScroll event (Firefox)

---
 src/xterm.js | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/xterm.js b/src/xterm.js
index ffefbb39..59746ce7 100644
--- a/src/xterm.js
+++ b/src/xterm.js
@@ -407,12 +407,23 @@
     Viewport.prototype.onWheel = function(ev) {
       // Fallback to WheelEvent.DOM_DELTA_PIXEL 
       var multiplier = 1;
-      if (ev.deltaMode === WheelEvent.DOM_DELTA_LINE) {
+      var delta = 0;
+      if (ev.type === 'DOMMouseScroll') {
+        if (ev.axis !== MouseScrollEvent.VERTICAL_AXIS) {
+          return;
+        } 
+        delta = ev.detail;
+        // Firefox treats ev.detail as lines, not pixels
         multiplier = this.currentRowHeight;
-      } else if (ev.deltaMode === WheelEvent.DOM_DELTA_PAGE) {
-        multiplier = this.currentRowHeight * this.terminal.rows;
+      } else if (ev.type === 'mousewheel') {
+        delta = ev.deltaY
+        if (ev.deltaMode === WheelEvent.DOM_DELTA_LINE) {
+          multiplier = this.currentRowHeight;
+        } else if (ev.deltaMode === WheelEvent.DOM_DELTA_PAGE) {
+          multiplier = this.currentRowHeight * this.terminal.rows;
+        }
       }
-      this.viewportElement.scrollTop += ev.deltaY * multiplier;
+      this.viewportElement.scrollTop += delta * multiplier;
       // Prevent the page from scrolling when the terminal scrolls
       ev.preventDefault();
     };