Editor font sizes can be adjusted with RootView.proto.setFontSize

spec/app/editor-spec.coffee

@@ -9,8 +9,7 @@ _ = require 'underscore'
 fs = require 'fs'
 
 describe "Editor", ->
-  buffer = null
-  editor = null
+  [rootView, buffer, editor] = []
 
   beforeEach ->
     rootView = new RootView(pathToOpen: require.resolve('fixtures/sample.js'))
@@ -247,6 +246,35 @@ describe "Editor", ->
       editor.scroller.trigger('scroll')
       expect(editor.gutter.scrollTop()).toBe 20
 
+  describe "font size", ->
+    it "sets the initial font size based on the value assigned to the root view", ->
+      rootView.setFontSize(20)
+      rootView.simulateDomAttachment()
+      newEditor = editor.splitRight()
+      expect(editor.css('font-size')).toBe '20px'
+      expect(newEditor.css('font-size')).toBe '20px'
+
+    describe "when the font size changes on the view", ->
+      it "updates the font sizes of editors and recalculates dimensions critical to cursor positioning", ->
+        rootView.attachToDom()
+        expect(editor.css('font-size')).not.toBe '30px'
+        lineHeightBefore = editor.lineHeight
+        charWidthBefore = editor.charWidth
+        editor.setCursorScreenPosition [5, 5]
+
+        rootView.setFontSize(30)
+
+        expect(editor.css('font-size')).toBe '30px'
+        expect(editor.lineHeight).toBeGreaterThan lineHeightBefore
+        expect(editor.charWidth).toBeGreaterThan charWidthBefore
+        expect(editor.getCursors()[0].position()).toEqual { top: 5 * editor.lineHeight, left: 5 * editor.charWidth }
+
+        # ensure we clean up font size subscription
+        editor.trigger('close')
+        rootView.setFontSize(22)
+        expect(editor.css('font-size')).toBe '30px'
+
+
   describe "cursor movement", ->
     describe "when the arrow keys are pressed", ->
       it "moves the cursor by a single row/column", ->

src/app/composite-cursor.coffee

@@ -33,6 +33,9 @@ class CompositeCursor
   removeCursor: (cursor) ->
     _.remove(@cursors, cursor)
 
+  updateAppearance: ->
+    cursor.updateAppearance() for cursor in @cursors
+
   moveCursors: (fn) ->
     fn(cursor) for cursor in @cursors
     @mergeCursors()

src/app/editor.coffee

@@ -212,6 +212,7 @@ class Editor extends View
   afterAttach: (onDom) ->
     return if @attached or not onDom
     @attached = true
+    @subscribeToFontSize()
     @calculateDimensions()
     @hiddenInput.width(@charWidth)
     @setMaxLineLength() if @softWrap
@@ -440,6 +441,17 @@ class Editor extends View
     @lineHeight = fragment.outerHeight()
     fragment.remove()
 
+  subscribeToFontSize: ->
+    return unless rootView = @rootView()
+    @setFontSize(rootView.getFontSize())
+    rootView.on "font-size-change.editor#{@id}", =>
+      @setFontSize(rootView.getFontSize())
+      @calculateDimensions()
+      @compositeCursor.updateAppearance()
+
+  setFontSize: (fontSize) ->
+    @css('font-size', fontSize + 'px') if fontSize
+
   getCursors: -> @compositeCursor.getCursors()
   moveCursorUp: -> @compositeCursor.moveUp()
   moveCursorDown: -> @compositeCursor.moveDown()
@@ -556,6 +568,7 @@ class Editor extends View
     @trigger 'before-remove'
     @unsubscribeFromBuffer()
     rootView = @rootView()
+    rootView?.off ".editor#{@id}"
     if @pane() then @pane().remove() else super
     rootView?.focus()
 

src/app/root-view.coffee

@@ -28,6 +28,7 @@ class RootView extends View
 
   extensions: null
   extensionStates: null
+  fontSize: null
 
   initialize: ({ pathToOpen }) ->
     @extensions = {}
@@ -135,3 +136,9 @@ class RootView extends View
   remove: ->
     editor.remove() for editor in @editors()
     super
+
+  setFontSize: (newFontSize) ->
+    [oldFontSize, @fontSize] = [@fontSize, newFontSize]
+    @trigger 'font-size-change' if oldFontSize != newFontSize
+
+  getFontSize: -> @fontSize

static/editor.css

@@ -2,7 +2,7 @@
   height: 100%;
   overflow: hidden;
   background: #333;
-  font: 18px Inconsolata, Monaco, Courier !important;
+  font: 18px Inconsolata, Monaco, Courier;
   color: white;
   cursor: default;
   -webkit-user-select: none;