From bc3c3577d4819a1d061f010824f226a2f6f91d12 Mon Sep 17 00:00:00 2001
From: Eden Halperin <eden@mapbox.com>
Date: Fri, 16 Jan 2015 11:48:14 -0800
Subject: [PATCH] slow down zoom if shift key is held, close #836

---
 js/ui/interaction.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/js/ui/interaction.js b/js/ui/interaction.js
index 6ab4cb98d68..c1ddfb2046b 100644
--- a/js/ui/interaction.js
+++ b/js/ui/interaction.js
@@ -197,6 +197,9 @@ function Interaction(el) {
                 }
             }
 
+            // Slow down zoom if shift key is held for more precise zooming
+            if (ev.shiftKey && value) value = value / 4;
+
             // Only fire the callback if we actually know what type of scrolling
             // device the user uses.
             if (type !== null) {