Start on TextEditorPresenter with lines state

src/text-editor-presenter.coffee

@@ -0,0 +1,20 @@
+module.exports =
+class TextEditorPresenter
+  constructor: ({@model, @clientHeight, @scrollTop, @lineHeight, @lineOverdrawMargin}) ->
+    @state = {}
+    @buildLinesState()
+
+  buildLinesState: ->
+    @state.lines = {}
+    startRow = Math.floor(@scrollTop / @lineHeight) - @lineOverdrawMargin
+    startRow = Math.max(0, startRow)
+    endRow = startRow + Math.ceil(@clientHeight / @lineHeight) + @lineOverdrawMargin
+    endRow = Math.min(@model.getScreenLineCount(), endRow)
+
+    for line, i in @model.tokenizedLinesForScreenRows(startRow, endRow)
+      row = startRow + i
+      @state.lines[line.id] = {
+        screenRow: row
+        tokens: line.tokens
+        top: row * @lineHeight
+      }