Add Renderer.clipScreenPosition

src/atom/line-map.coffee

@@ -66,7 +66,10 @@ class LineMap
     new Range(start, end)
 
   clipOutputPosition: (outputPosition, options) ->
-    @translatePosition('outputDelta', 'outputDelta', outputPosition, options)
+    @clipPosition('outputDelta', outputPosition, options)
+
+  clipPosition: (deltaType, position, options) ->
+    @translatePosition(deltaType, deltaType, position, options)
 
   spliceByDelta: (deltaType, startRow, rowCount, lineFragments) ->
     stopRow = startRow + rowCount
@@ -119,6 +122,7 @@ class LineMap
         targetDelta.column = 0
       else
         targetDelta.column = maxTargetColumn - 1
+        return @clipPosition(targetDeltaType, targetDelta)
     else if sourcePosition.column > maxSourceColumn and wrapBeyondNewlines
       targetDelta.row++
       targetDelta.column = 0

src/atom/renderer.coffee

@@ -90,6 +90,9 @@ class Renderer
   bufferPositionForScreenPosition: (position) ->
     @lineMap.inputPositionForOutputPosition(position)
 
+  clipScreenPosition: (position, options={}) ->
+    @lineMap.clipOutputPosition(position, options)
+
   handleBufferChange: (e) ->
     for row, folds of @activeFolds
       for fold in folds
@@ -133,7 +136,7 @@ class Renderer
           suffix = buildLinesForBufferRows(fold.end.row, endRow, fold.end.column, currentScreenLineLength)
           return _.compact _.flatten [prefix, placeholder, suffix]
 
-      if wrapColumn
+      if wrapColumn?
         line = line.splitAt(wrapColumn)[0]
         line.outputDelta = new Point(1, 0)
         [line].concat buildLinesForBufferRows(startRow, endRow, startColumn + wrapColumn)