Implement canvas offset to allow smooth scroll

atom-minimap · Dec 15, 2014 · 57accd3 · 57accd3
1 parent 6555bfe
commit 57accd3
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Showing 2 changed files with 8 additions and 0 deletions.
diff --git a/lib/minimap-element.coffee b/lib/minimap-element.coffee
@@ -79,6 +79,8 @@ class MinimapElement extends HTMLElement
     @visibleArea.style.top = (@minimap.getTextEditorScrollTop() - @minimap.getMinimapScrollTop()) + 'px'
     @visibleArea.style.left = (@minimap.getTextEditorScrollLeft()) + 'px'
 
+    @canvas.style.top = (@minimap.getFirstVisibleScreenRow() * @minimap.getLineHeight() - @minimap.getMinimapScrollTop()) + 'px'
+
     @updateCanvas()
 
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diff --git a/spec/minimap-element-spec.coffee b/spec/minimap-element-spec.coffee
@@ -112,6 +112,12 @@ describe 'MinimapElement', ->
         expect(visibleArea.offsetTop).toBeCloseTo(minimap.getTextEditorScrollTop() - minimap.getMinimapScrollTop(), 0)
         expect(visibleArea.offsetLeft).toBeCloseTo(minimap.getTextEditorScrollLeft(), 0)
 
+      it 'offsets the canvas when the scroll does not match line height', ->
+        editor.setScrollTop(1004)
+        nextAnimationFrame()
+
+        expect(canvas.offsetTop).toEqual(-2)
+
       describe 'when the editor is scrolled', ->
         beforeEach ->
           editor.setScrollTop(2000)