Take double width chars into account when soft wrapping

spec/display-buffer-spec.coffee

@@ -60,6 +60,16 @@ describe "DisplayBuffer", ->
       changeHandler.reset()
 
     describe "rendering of soft-wrapped lines", ->
+      describe "when there are double width characters", ->
+        it "takes them into account when finding the soft wrap column", ->
+          displayBuffer.setDoubleWidthCharWidth(5)
+          buffer.setText("私たちのフ是一个地方，数千名学生12345业余爱们的板作为우리포럼hello world this is a pretty long latin line")
+
+          expect(displayBuffer.tokenizedLineForScreenRow(0).text).toBe("私たちのフ是一个地方")
+          expect(displayBuffer.tokenizedLineForScreenRow(1).text).toBe("，数千名学生12345业余爱")
+          expect(displayBuffer.tokenizedLineForScreenRow(2).text).toBe("们的板作为우리포럼hello ")
+          expect(displayBuffer.tokenizedLineForScreenRow(3).text).toBe("world this is a pretty long latin line")
+
       describe "when editor.softWrapAtPreferredLineLength is set", ->
         it "uses the preferred line length as the soft wrap column when it is less than the configured soft wrap column", ->
           atom.config.set('editor.preferredLineLength', 100)

src/display-buffer.coffee

@@ -195,6 +195,12 @@ class DisplayBuffer extends Model
       @defaultCharWidth = defaultCharWidth
     defaultCharWidth
 
+  getDoubleWidthCharWidth: -> @doubleWidthCharWidth
+  setDoubleWidthCharWidth: (doubleWidthCharWidth) ->
+    if doubleWidthCharWidth isnt @doubleWidthCharWidth
+      @doubleWidthCharWidth = doubleWidthCharWidth
+    doubleWidthCharWidth
+
   getCursorWidth: -> 1
 
   scrollToScreenRange: (screenRange, options = {}) ->
@@ -282,8 +288,13 @@ class DisplayBuffer extends Model
         else
           charLength = 1
 
-        charWidth = @getDefaultCharWidth()
+        if iterator.hasDoubleWidthCharacterAt(textIndex)
+          charWidth = @getDoubleWidthCharWidth()
+        else
+          charWidth = @getDefaultCharWidth()
+
         return column if currentWidth + charWidth > lineMaxWidth
+
         currentWidth += charWidth
         column += charLength
         textIndex += charLength

src/token-iterator.coffee

@@ -1,4 +1,5 @@
 {SoftTab, HardTab, PairedCharacter, SoftWrapIndent} = require './special-token-symbols'
+{isDoubleWidthCharacter} = require './text-utils'
 
 module.exports =
 class TokenIterator
@@ -82,5 +83,8 @@ class TokenIterator
   isPairedCharacter: ->
     @line.specialTokens[@index] is PairedCharacter
 
+  hasDoubleWidthCharacterAt: (charIndex) ->
+    isDoubleWidthCharacter(@getText()[charIndex])
+
   isAtomic: ->
     @isSoftTab() or @isHardTab() or @isSoftWrapIndentation() or @isPairedCharacter()