Add allowEOL param to screenPositionFromBufferPosition

spec/atom/line-wrapper-spec.coffee

@@ -174,19 +174,28 @@ fdescribe "LineWrapper", ->
           expect(line2.endColumn).toBe 14
           expect(line2.textLength).toBe 3
 
-  describe ".screenPositionFromBufferPosition(point)", ->
+  describe ".screenPositionFromBufferPosition(point, allowEOL=false)", ->
     it "translates the given buffer position to a screen position, accounting for wrapped lines", ->
       # before any wrapped lines
       expect(wrapper.screenPositionFromBufferPosition([0, 5])).toEqual([0, 5])
+      expect(wrapper.screenPositionFromBufferPosition([0, 29])).toEqual([0, 29])
 
       # on a wrapped line
       expect(wrapper.screenPositionFromBufferPosition([3, 5])).toEqual([3, 5])
       expect(wrapper.screenPositionFromBufferPosition([3, 50])).toEqual([3, 50])
-      expect(wrapper.screenPositionFromBufferPosition([3, 51])).toEqual([4, 0])
+      expect(wrapper.screenPositionFromBufferPosition([3, 62])).toEqual([4, 11])
 
       # following a wrapped line
       expect(wrapper.screenPositionFromBufferPosition([4, 5])).toEqual([5, 5])
 
+    describe "when allowEOL is true", ->
+      it "preserves a position at the end of a wrapped screen line ", ->
+        expect(wrapper.screenPositionFromBufferPosition([3, 51], true)).toEqual([3, 51])
+
+    describe "when allowEOL is false", ->
+      it "translates a position at the end of a wrapped screen line to the begining of the next screen line", ->
+        expect(wrapper.screenPositionFromBufferPosition([3, 51])).toEqual([4, 0])
+
   describe ".bufferPositionFromScreenPosition(point)", ->
     it "translates the given screen position to a buffer position, account for wrapped lines", ->
       # before any wrapped lines

src/atom/line-wrapper.coffee

@@ -91,15 +91,22 @@ class LineWrapper
     end = @screenPositionFromBufferPosition(bufferRange.end)
     new Range(start,end)
 
-  screenPositionFromBufferPosition: (bufferPosition) ->
+  screenPositionFromBufferPosition: (bufferPosition, allowEOL=false) ->
     bufferPosition = Point.fromObject(bufferPosition)
     row = 0
     for wrappedLine in @wrappedLines[0...bufferPosition.row]
       row += wrappedLine.screenLines.length
 
     column = bufferPosition.column
-    for screenLine in @wrappedLines[bufferPosition.row].screenLines
-      break if screenLine.endColumn > bufferPosition.column
+
+    screenLines = @wrappedLines[bufferPosition.row].screenLines
+    for screenLine, index in screenLines
+      break if index == screenLines.length - 1
+      if allowEOL
+        break if screenLine.endColumn >= bufferPosition.column
+      else
+        break if screenLine.endColumn > bufferPosition.column
+
       column -= screenLine.textLength
       row++