Make cursor blink by changing CSS visibility with setInterval

This is actually more efficient than the CSS animation we were doing previously, because it doesn't force the cursor to be sampled at 60 FPS for something that changes around twice a second.

spec/app/editor-spec.coffee

@@ -935,11 +935,11 @@ describe "Editor", ->
 
         editor.setSelectedBufferRange([[0, 0], [3, 0]])
         expect(editor.getSelection().isEmpty()).toBeFalsy()
-        expect(cursorView).not.toBeVisible()
+        expect(cursorView.css('visibility')).toBe 'hidden'
 
         editor.setCursorBufferPosition([1, 3])
         expect(editor.getSelection().isEmpty()).toBeTruthy()
-        expect(cursorView).toBeVisible()
+        expect(cursorView.css('visibility')).toBe 'visible'
 
       describe "auto-scrolling", ->
         it "only auto-scrolls when the last cursor is moved", ->
@@ -1794,10 +1794,10 @@ describe "Editor", ->
 
         editor.setCursorScreenPosition([2,0])
         expect(editor.lineElementForScreenRow(2)).toMatchSelector('.fold.selected')
-        expect(editor.find('.cursor').css('display')).toBe 'none'
+        expect(editor.find('.cursor').css('visibility')).toBe 'hidden'
 
         editor.setCursorScreenPosition([3,0])
-        expect(editor.find('.cursor').css('display')).toBe 'block'
+        expect(editor.find('.cursor').css('visibility')).toBe 'visible'
 
     describe "when a selected fold is scrolled into view (and the fold line was not previously rendered)", ->
       it "renders the fold's line element with the 'selected' class", ->

src/app/cursor-view.coffee

@@ -9,16 +9,19 @@ class CursorView extends View
   @content: ->
     @pre class: 'cursor idle', => @raw ' '
 
+  blinkPeriod: 800
   editor: null
   visible: true
 
   needsUpdate: true
   needsAutoscroll: true
   needsRemoval: false
+  shouldPauseBlinking: false
 
   initialize: (@cursor, @editor) ->
-    @cursor.on 'change-screen-position.cursor-view', (screenPosition, { bufferChange, autoscroll }) =>
+    @cursor.on 'change-screen-position.cursor-view', (screenPosition, { autoscroll }) =>
       @needsUpdate = true
+      @shouldPauseBlinking = true
       @needsAutoscroll = (autoscroll ? true) and @cursor?.isLastCursor()
       @editor.requestDisplayUpdate()
 
@@ -43,9 +46,13 @@ class CursorView extends View
     unless _.isEqual(@lastPixelPosition, pixelPosition)
       changedPosition = true
       @css(pixelPosition)
-#       @removeIdleClassTemporarily() unless bufferChange
       @trigger 'cursor-move'
 
+    if @shouldPauseBlinking
+      @resetBlinking()
+    else if !@startBlinkingTimeout
+      @startBlinking()
+
     @setVisible(@cursor.isVisible() and not @editor.isFoldedAtScreenRow(screenPosition.row))
 
   getPixelPosition: ->
@@ -54,7 +61,27 @@ class CursorView extends View
   setVisible: (visible) ->
     unless @visible == visible
       @visible = visible
-      @toggle(@visible)
+      if @visible
+        @css('visibility', '')
+      else
+        @css('visibility', 'hidden')
+
+  toggleVisible: ->
+    @setVisible(not @visible) if @cursor.isVisible
+
+  stopBlinking: ->
+    clearInterval(@blinkInterval) if @blinkInterval
+    @blinkInterval = null
+    @setVisible(true) if @cursor.isVisible
+
+  startBlinking: ->
+    return if @blinkInterval?
+    blink = => @toggleVisible()
+    @blinkInterval = setInterval(blink, @blinkPeriod / 2)
+
+  resetBlinking: ->
+    @stopBlinking()
+    @startBlinking()
 
   getBufferPosition: ->
     @cursor.getBufferPosition()

src/app/editor.coffee

@@ -768,7 +768,7 @@ class Editor extends View
 
   syncCursorAnimations: ->
     for cursorView in @getCursorViews()
-      do (cursorView) -> cursorView.resetCursorAnimation()
+      do (cursorView) -> cursorView.resetBlinking()
 
   autoscroll: (options={}) ->
     for cursorView in @getCursorViews() when cursorView.needsAutoscroll