Move scroll margin into TextEditorPresenter

src/display-buffer.coffee

@@ -362,35 +362,12 @@ class DisplayBuffer extends Model
     {start, end} = selection.getScreenRange()
     @intersectsVisibleRowRange(start.row, end.row + 1)
 
-  scrollToScreenRangeLogical: (screenRange, options) ->
-    top = screenRange.start.row
-    left = screenRange.start.column
-    bottom = screenRange.end.row
-    right = screenRange.end.column
-
-    if options?.center
-      center = (top + bottom) / 2
-      top = center - @getLogicalHeight() / 2
-      bottom = center + @getLogicalHeight() / 2
-    else
-      top -= @getVerticalScrollMargin()
-      bottom += @getVerticalScrollMargin()
-
-    left -= @getHorizontalScrollMargin()
-    right += @getHorizontalScrollMargin()
-
-    top = Math.max(0, Math.min(@getLineCount() - 1, top))
-    bottom = Math.max(0, Math.min(@getLineCount() - 1, bottom))
-    left = Math.max(0, left)
-    right = Math.max(0, right)
-
-    screenRange = new Range(new Point(top, left), new Point(bottom, right))
-
+  logicalScrollToScreenRange: (screenRange, options) ->
     scrollEvent = {screenRange, options}
     @emitter.emit "did-change-scroll-position", scrollEvent
 
   scrollToScreenRange: (screenRange, options) ->
-    @scrollToScreenRangeLogical(screenRange, options)
+    @logicalScrollToScreenRange(screenRange, options)
 
     verticalScrollMarginInPixels = @getVerticalScrollMarginInPixels()
     horizontalScrollMarginInPixels = @getHorizontalScrollMarginInPixels()
@@ -414,9 +391,10 @@ class DisplayBuffer extends Model
 
     if global.enableLogs
       console.log "====== DB ======"
-      console.log "Client Height: #{@getClientHeight()}"
-      console.log "#{desiredScrollTop}/#{desiredScrollBottom}"
-      console.log "#{@getScrollTop()}/#{@getScrollBottom()}"
+      console.log "Screen Range: #{screenRange.toString()}"
+      console.log "Client Width: #{@getClientWidth()}"
+      console.log "#{desiredScrollLeft}/#{desiredScrollRight}"
+      console.log "#{@getScrollLeft()}/#{@getScrollRight()}"
       console.log "================"
 
     if options?.reversed ? true

src/text-editor-presenter.coffee

@@ -1472,40 +1472,69 @@ class TextEditorPresenter
 
     @emitDidUpdateState()
 
+  getVerticalScrollMarginInPixels: ->
+    @model.getVerticalScrollMargin() * @lineHeight
+
+  getHorizontalScrollMarginInPixels: ->
+    @model.getHorizontalScrollMargin() * @baseCharacterWidth
+
   updateScrollPosition: ->
     return unless @pendingScrollLogicalPosition?
 
     {screenRange, options} = @pendingScrollLogicalPosition
 
+    verticalScrollMarginInPixels = @getVerticalScrollMarginInPixels()
+    horizontalScrollMarginInPixels = @getHorizontalScrollMarginInPixels()
+
     {top, left} = @pixelRectForScreenRange(new Range(screenRange.start, screenRange.start))
     {top: endTop, left: endLeft, height: endHeight} = @pixelRectForScreenRange(new Range(screenRange.end, screenRange.end))
     bottom = endTop + endHeight
     right = endLeft
 
-    left += @scrollLeft
-    right += @scrollLeft
     top += @scrollTop
     bottom += @scrollTop
+    left += @scrollLeft
+    right += @scrollLeft
+
+    if options?.center
+      desiredScrollCenter = (top + bottom) / 2
+      unless @getScrollTop() < desiredScrollCenter < @getScrollBottom()
+        desiredScrollTop = desiredScrollCenter - @getClientHeight() / 2
+        desiredScrollBottom = desiredScrollCenter + @getClientHeight() / 2
+    else
+      desiredScrollTop = top - verticalScrollMarginInPixels
+      desiredScrollBottom = bottom + verticalScrollMarginInPixels
+
+    desiredScrollLeft = left - horizontalScrollMarginInPixels
+    desiredScrollRight = right + horizontalScrollMarginInPixels
+
+    if global.enableLogs
+      console.log "====== DB ======"
+      console.log "Screen Range: #{screenRange.toString()}"
+      console.log "Client Width: #{@getClientWidth()}"
+      console.log "#{desiredScrollLeft}/#{desiredScrollRight}"
+      console.log "#{@getScrollLeft()}/#{@getScrollRight()}"
+      console.log "================"
 
     if options?.reversed ? true
-      if bottom > @getScrollBottom()
-        @setScrollBottom(bottom)
-      if top < @getScrollTop()
-        @setScrollTop(top)
+      if desiredScrollBottom > @getScrollBottom()
+        @setScrollBottom(desiredScrollBottom)
+      if desiredScrollTop < @getScrollTop()
+        @setScrollTop(desiredScrollTop)
 
-      if right > @getScrollRight()
-        @setScrollRight(right)
-      if left < @getScrollLeft()
-        @setScrollLeft(left)
+      if desiredScrollRight > @getScrollRight()
+        @setScrollRight(desiredScrollRight)
+      if desiredScrollLeft < @getScrollLeft()
+        @setScrollLeft(desiredScrollLeft)
     else
-      if top < @getScrollTop()
-        @setScrollTop(top)
-      if bottom > @getScrollBottom()
-        @setScrollBottom(bottom)
+      if desiredScrollTop < @getScrollTop()
+        @setScrollTop(desiredScrollTop)
+      if desiredScrollBottom > @getScrollBottom()
+        @setScrollBottom(desiredScrollBottom)
 
-      if left < @getScrollLeft()
-        @setScrollLeft(left)
-      if right > @getScrollRight()
-        @setScrollRight(right)
+      if desiredScrollLeft < @getScrollLeft()
+        @setScrollLeft(desiredScrollLeft)
+      if desiredScrollRight > @getScrollRight()
+        @setScrollRight(desiredScrollRight)
 
     @pendingScrollLogicalPosition = null