Re-wrap lines when window size changes.

spec/atom/editor-spec.coffee

@@ -79,10 +79,21 @@ describe "Editor", ->
         expect(editor.lines.find('.line:eq(8)').text()).toBe ': right.push(current);'
         expect(editor.lines.find('.line:eq(9)').text()).toBe '    }'
 
-      it "unwraps lines when softwrap is disabled", ->
+      it "changes the max line length when the window size changes", ->
+        editor.width(editor.charWidth * 40)
+        $(window).trigger 'resize'
+        expect(editor.lines.find('.line').length).toBe 19
+        expect(editor.lines.find('pre:eq(4)').text()).toBe "left = [], right = [];"
+        expect(editor.lines.find('pre:eq(5)').text()).toBe "    while(items.length > 0) {"
+
+      it "unwraps lines and cancels window resize listener when softwrap is disabled", ->
         editor.toggleSoftWrap()
         expect(editor.lines.find('.line:eq(3)').text()).toBe '    var pivot = items.shift(), current, left = [], right = [];'
 
+        spyOn(editor, 'setMaxLineLength')
+        $(window).trigger 'resize'
+        expect(editor.setMaxLineLength).not.toHaveBeenCalled()
+
   describe "cursor movement", ->
     describe ".setCursorPosition({row, column})", ->
       beforeEach ->

src/atom/editor.coffee

@@ -178,7 +178,7 @@ class Editor extends View
   toggleSoftWrap: ->
     @setSoftWrap(not @softWrap)
 
-  setSoftWrap: (@softWrap) ->
+  setMaxLineLength: ->
     maxLength =
       if @softWrap
         Math.floor(@width() / @charWidth)
@@ -187,6 +187,14 @@ class Editor extends View
 
     @lineWrapper.setMaxLength(maxLength)
 
+  setSoftWrap: (@softWrap) ->
+    @setMaxLineLength()
+    if @softWrap
+      @_setMaxLineLength = => @setMaxLineLength()
+      $(window).on 'resize', @_setMaxLineLength
+    else
+      $(window).off 'resize', @_setMaxLineLength
+
   clipPosition: ({row, column}) ->
     if row > @buffer.lastRow()
       row = @buffer.lastRow()