Don't measure lineHeight/defaultCharWidth when editor is hidden

spec/editor-component-spec.coffee

@@ -764,3 +764,24 @@ describe "EditorComponent", ->
 
         expect(editor.consolidateSelections).toHaveBeenCalled()
         expect(event.abortKeyBinding).toHaveBeenCalled()
+
+  describe "hiding and showing the editor", ->
+    describe "when fontSize, fontFamily, or lineHeight changes while the editor is hidden", ->
+      it "does not attempt to measure the lineHeight and defaultCharWidth until the editor becomes visible again", ->
+        wrapperView.hide()
+        initialLineHeight = editor.getLineHeight()
+        initialCharWidth = editor.getDefaultCharWidth()
+
+        component.setLineHeight(2)
+        expect(editor.getLineHeight()).toBe initialLineHeight
+        expect(editor.getDefaultCharWidth()).toBe initialCharWidth
+        component.setFontSize(22)
+        expect(editor.getLineHeight()).toBe initialLineHeight
+        expect(editor.getDefaultCharWidth()).toBe initialCharWidth
+        component.setFontFamily('monospace')
+        expect(editor.getLineHeight()).toBe initialLineHeight
+        expect(editor.getDefaultCharWidth()).toBe initialCharWidth
+
+        wrapperView.show()
+        expect(editor.getLineHeight()).not.toBe initialLineHeight
+        expect(editor.getDefaultCharWidth()).not.toBe initialCharWidth

src/editor-component.coffee

@@ -31,7 +31,7 @@ EditorComponent = React.createClass
   mouseWheelScreenRow: null
 
   render: ->
-    {focused, fontSize, lineHeight, fontFamily, showIndentGuide, showInvisibles} = @state
+    {focused, fontSize, lineHeight, fontFamily, showIndentGuide, showInvisibles, visible} = @state
     {editor, cursorBlinkPeriod, cursorBlinkResumeDelay} = @props
     maxLineNumberDigits = editor.getScreenLineCount().toString().length
     invisibles = if showInvisibles then @state.invisibles else {}
@@ -64,7 +64,7 @@ EditorComponent = React.createClass
         scrollTop, scrollLeft, scrollHeight, scrollWidth, @scrollingVertically,
         @cursorsMoved, @selectionChanged, @selectionAdded, cursorBlinkPeriod,
         cursorBlinkResumeDelay, @onInputFocused, @onInputBlurred, @mouseWheelScreenRow,
-        invisibles
+        invisibles, visible
       }
 
       ScrollbarComponent
@@ -106,7 +106,8 @@ EditorComponent = React.createClass
     renderedEndRow = Math.min(editor.getScreenLineCount(), visibleEndRow + lineOverdrawMargin)
     [renderedStartRow, renderedEndRow]
 
-  getInitialState: -> {}
+  getInitialState: ->
+    visible: true
 
   getDefaultProps: ->
     cursorBlinkPeriod: 800
@@ -467,3 +468,9 @@ EditorComponent = React.createClass
   lineNodeForScreenRow: (screenRow) -> @refs.scrollView.lineNodeForScreenRow(screenRow)
 
   lineNumberNodeForScreenRow: (screenRow) -> @refs.gutter.lineNumberNodeForScreenRow(screenRow)
+
+  hide: ->
+    @setState(visible: false)
+
+  show: ->
+    @setState(visible: true)

src/editor-scroll-view-component.coffee

@@ -16,7 +16,7 @@ EditorScrollViewComponent = React.createClass
   overflowChangedWhilePaused: false
 
   render: ->
-    {editor, fontSize, fontFamily, lineHeight, showIndentGuide, invisibles} = @props
+    {editor, fontSize, fontFamily, lineHeight, showIndentGuide, invisibles, visible} = @props
     {renderedRowRange, pendingChanges, scrollTop, scrollLeft, scrollHeight, scrollWidth, scrollingVertically, mouseWheelScreenRow} = @props
     {selectionChanged, selectionAdded, cursorBlinkPeriod, cursorBlinkResumeDelay, cursorsMoved, onInputFocused, onInputBlurred} = @props
 
@@ -37,7 +37,8 @@ EditorScrollViewComponent = React.createClass
       LinesComponent {
         ref: 'lines', editor, fontSize, fontFamily, lineHeight, showIndentGuide,
         renderedRowRange, pendingChanges, scrollTop, scrollLeft, scrollingVertically,
-        selectionChanged, scrollHeight, scrollWidth, mouseWheelScreenRow, invisibles
+        selectionChanged, scrollHeight, scrollWidth, mouseWheelScreenRow, invisibles,
+        visible
       }
 
   componentDidMount: ->

src/lines-component.coffee

@@ -35,7 +35,7 @@ LinesComponent = React.createClass
 
   shouldComponentUpdate: (newProps) ->
     return true if newProps.selectionChanged
-    return true unless isEqualForProperties(newProps, @props,  'renderedRowRange', 'fontSize', 'fontFamily', 'lineHeight', 'scrollTop', 'scrollLeft', 'showIndentGuide', 'scrollingVertically', 'invisibles')
+    return true unless isEqualForProperties(newProps, @props,  'renderedRowRange', 'fontSize', 'fontFamily', 'lineHeight', 'scrollTop', 'scrollLeft', 'showIndentGuide', 'scrollingVertically', 'invisibles', 'visible')
 
     {renderedRowRange, pendingChanges} = newProps
     for change in pendingChanges
@@ -44,7 +44,9 @@ LinesComponent = React.createClass
     false
 
   componentDidUpdate: (prevProps) ->
-    @measureLineHeightAndCharWidth() unless isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily', 'lineHeight')
+    {visible} = @props
+    if visible and not isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily', 'lineHeight', 'visible')
+      @measureLineHeightAndCharWidth()
     @clearScreenRowCaches() unless prevProps.lineHeight is @props.lineHeight
     @removeLineNodes() unless isEqualForProperties(prevProps, @props, 'showIndentGuide', 'invisibles')
     @updateLines()

src/react-editor-view.coffee

@@ -82,3 +82,11 @@ class ReactEditorView extends View
       @component.onFocus()
     else
       @focusOnAttach = true
+
+  hide: ->
+    super
+    @component.hide()
+
+  show: ->
+    super
+    @component.show()