🐛 Change minimap width adjustments to avoid update on every DOM poll

atom-minimap · Dec 17, 2014 · cca596c · cca596c
1 parent fceb40b
commit cca596c
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Showing 2 changed files with 39 additions and 12 deletions.
diff --git a/lib/minimap-element.coffee b/lib/minimap-element.coffee
@@ -29,6 +29,8 @@ class MinimapElement extends HTMLElement
         else if @scrollIndicator?
           @disposeScrollIndicator()
 
+        @requestUpdate() if @attached
+
       'minimap.textOpacity': (@textOpacity) =>
         @requestForcedUpdate() if @attached
 
@@ -134,20 +136,23 @@ class MinimapElement extends HTMLElement
 
   measureHeightAndWidth: ->
     @height = @clientHeight
+    @width = @clientWidth
+    canvasWidth = @width
+
+    return unless @isVisible()
 
     if @adjustToSoftWrap
       lineLength = atom.config.get('editor.preferredLineLength')
       softWrap = atom.config.get('editor.softWrap')
       width = lineLength * @minimap.getCharWidth()
 
-      @width = width if softWrap and lineLength and (not @width? or width < @width)
+      @marginRight = width - @width if softWrap and lineLength and width < @width
+      canvasWidth = width
     else
-      @width = @clientWidth
-
-    return unless @isVisible()
+      delete @marginRight
 
-    if @width isnt @canvas.width or @height isnt @canvas.height
-      @canvas.width = @width * devicePixelRatio
+    if canvasWidth isnt @canvas.width or @height isnt @canvas.height
+      @canvas.width = canvasWidth * devicePixelRatio
       @canvas.height = (@height + @minimap.getLineHeight()) * devicePixelRatio
 
   getTextEditor: -> @minimap.getTextEditor()
@@ -183,9 +188,9 @@ class MinimapElement extends HTMLElement
     return unless @attached and @isVisible()
 
     if @adjustToSoftWrap
-      @style.width = @width + 'px'
+      @style.marginRight = @marginRight + 'px'
     else
-      @style.width = null
+      @style.marginRight = null
 
     visibleAreaLeft = @minimap.getTextEditorScrollLeft()
     visibleAreaTop = @minimap.getTextEditorScrollTop() - @minimap.getMinimapScrollTop()
@@ -205,9 +210,11 @@ class MinimapElement extends HTMLElement
       editorHeight = @getTextEditor().getHeight()
       indicatorHeight = editorHeight * (editorHeight / @minimap.getHeight())
       indicatorScroll = (editorHeight - indicatorHeight) * @minimap.getTextEditorScrollRatio()
+      indicatorOffset = 0
+      indicatorOffset = @marginRight if @adjustToSoftWrap
 
       @scrollIndicator.style.height = indicatorHeight + 'px'
-      @transformElement @scrollIndicator, @makeTranslate(0, indicatorScroll)
+      @transformElement @scrollIndicator, @makeTranslate(indicatorOffset, indicatorScroll)
 
       @disposeScrollIndicator() if not @minimap.canScroll()
 

diff --git a/spec/minimap-element-spec.coffee b/spec/minimap-element-spec.coffee
@@ -292,22 +292,42 @@ describe 'MinimapElement', ->
         expect(Array::indexOf.call(editorElement.shadowRoot.children, minimapElement)).toEqual(0)
 
     describe 'when minimap.adjustMinimapWidthToSoftWrap is true', ->
+      [minimapWidth] = []
       beforeEach ->
+        minimapWidth = minimapElement.offsetWidth
+
         atom.config.set 'editor.softWrap', true
         atom.config.set 'editor.softWrapAtPreferredLineLength', true
         atom.config.set 'editor.preferredLineLength', 2
 
         atom.config.set 'minimap.adjustMinimapWidthToSoftWrap', true
         nextAnimationFrame()
 
-      it 'adjusts the width of the minimap', ->
-        expect(minimapElement.offsetWidth).toEqual(4)
+      it 'adjusts the width of the minimap canvas', ->
+        expect(minimapElement.canvas.width).toEqual(4)
+
+      it 'offsets the minimap by the difference', ->
+        expect(realOffsetLeft(minimapElement)).toBeCloseTo(editorElement.clientWidth - 4, -1)
+        expect(minimapElement.clientWidth).toBeCloseTo(minimapWidth, -1)
 
       describe 'the dom polling routine', ->
         it 'does not change the value', ->
           advanceClock(150)
           nextAnimationFrame()
-          expect(minimapElement.offsetWidth).toEqual(4)
+          expect(minimapElement.canvas.width).toEqual(4)
+
+      describe 'and when minimap.minimapScrollIndicator setting is true', ->
+        beforeEach ->
+          editor.setText(mediumSample)
+          editor.setScrollTop(50)
+          nextAnimationFrame()
+
+          atom.config.set 'minimap.minimapScrollIndicator', true
+          nextAnimationFrame()
+
+        it 'offsets the scroll indicator by the difference', ->
+          indicator = minimapElement.shadowRoot.querySelector('.minimap-scroll-indicator')
+          expect(realOffsetLeft(indicator)).toBeCloseTo(2, -1)
 
       describe 'and then disabled', ->
         beforeEach ->