From 7d2d0f2037b851a7855ccbc563309f84abbab8c8 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Tue, 13 Mar 2012 16:09:11 -0600
Subject: [PATCH] Add a drop shadow to gutter when horizontal scroller is
 scrolled right.

---
 spec/atom/editor-spec.coffee | 15 +++++++++++++++
 src/atom/editor.coffee       |  6 ++++++
 2 files changed, 21 insertions(+)

diff --git a/spec/atom/editor-spec.coffee b/spec/atom/editor-spec.coffee
index 48c8f789c..ee619452f 100644
--- a/spec/atom/editor-spec.coffee
+++ b/spec/atom/editor-spec.coffee
@@ -161,6 +161,21 @@ describe "Editor", ->
         editor.createFold([[3, 10], [5, 1]])
         expect(editor.gutter.find('.line-number:eq(3)').text()).toBe '4'
         expect(editor.gutter.find('.line-number:eq(4)').text()).toBe '7'
+    it "adds a drop shadow when the horizontal scroller is scrolled to the right", ->
+      editor.attachToDom()
+      editor.width(100)
+
+      expect(editor.gutter).not.toHaveClass('drop-shadow')
+
+      editor.horizontalScroller.scrollLeft(10)
+      editor.horizontalScroller.trigger('scroll')
+
+      expect(editor.gutter).toHaveClass('drop-shadow')
+
+      editor.horizontalScroller.scrollLeft(0)
+      editor.horizontalScroller.trigger('scroll')
+
+      expect(editor.gutter).not.toHaveClass('drop-shadow')
 
   describe "cursor movement", ->
     describe ".setCursorScreenPosition({row, column})", ->
diff --git a/src/atom/editor.coffee b/src/atom/editor.coffee
index d08ae90a1..697bac867 100644
--- a/src/atom/editor.coffee
+++ b/src/atom/editor.coffee
@@ -127,6 +127,12 @@ class Editor extends View
         position.left = Math.min(position.left, @horizontalScroller.width() - @charWidth)
       @hiddenInput.css(position)
 
+    @horizontalScroller.on 'scroll', =>
+      if @horizontalScroller.scrollLeft() == 0
+        @gutter.removeClass('drop-shadow')
+      else
+        @gutter.addClass('drop-shadow')
+
     @one 'attach', =>
       @calculateDimensions()
       @hiddenInput.width(@charWidth)