wip

src/lines-presenter.coffee

@@ -0,0 +1,41 @@
+module.exports =
+class LinesPresenter
+  startRow: null
+  endRow: null
+  lineHeight: null
+
+  constructor: (@presenter) ->
+    @lines = {}
+
+  getState: ->
+    visibleLineIds = {}
+    row = @startRow
+    while row < @endRow
+      line = @presenter.model.tokenizedLineForScreenRow(row)
+      unless line?
+        throw new Error("No line exists for row #{row}. Last screen row: #{@model.getLastScreenRow()}")
+
+      visibleLineIds[line.id] = true
+      if @lines.hasOwnProperty(line.id)
+        lineState = @lines[line.id]
+        lineState.screenRow = row
+        lineState.top = (row - @startRow) * @lineHeight
+        lineState.decorationClasses = @presenter.lineDecorationClassesForRow(row)
+      else
+        @lines[line.id] =
+          screenRow: row
+          text: line.text
+          tokens: line.tokens
+          isOnlyWhitespace: line.isOnlyWhitespace()
+          endOfLineInvisibles: line.endOfLineInvisibles
+          indentLevel: line.indentLevel
+          tabLength: line.tabLength
+          fold: line.fold
+          top: (row - @startRow) * @lineHeight
+          decorationClasses: @presenter.lineDecorationClassesForRow(row)
+      row++
+
+    for id, line of @lines
+      delete @lines[id] unless visibleLineIds.hasOwnProperty(id)
+
+    @lines

src/text-editor-presenter.coffee

@@ -2,6 +2,7 @@
 {Point, Range} = require 'text-buffer'
 _ = require 'underscore-plus'
 Decoration = require './decoration'
+LinesPresenter = require './lines-presenter'
 
 module.exports =
 class TextEditorPresenter
@@ -20,6 +21,8 @@ class TextEditorPresenter
     @measuredHorizontalScrollbarHeight = horizontalScrollbarHeight
     @measuredVerticalScrollbarWidth = verticalScrollbarWidth
     @gutterWidth ?= 0
+    @tileCount ?= 3
+    @linesPresentersByTileIndex = {}
 
     @disposables = new CompositeDisposable
     @emitter = new Emitter
@@ -74,6 +77,7 @@ class TextEditorPresenter
     @updateHiddenInputState() if @shouldUpdateHiddenInputState
     @updateContentState() if @shouldUpdateContentState
     @updateDecorations() if @shouldUpdateDecorations
+    @updateTilesState() if @shouldUpdateLinesState
     @updateLinesState() if @shouldUpdateLinesState
     @updateCursorsState() if @shouldUpdateCursorsState
     @updateOverlaysState() if @shouldUpdateOverlaysState
@@ -205,6 +209,7 @@ class TextEditorPresenter
       content:
         scrollingVertically: false
         cursorsVisible: false
+        tiles: {}
         lines: {}
         highlights: {}
         overlays: {}
@@ -229,6 +234,7 @@ class TextEditorPresenter
     @updateHiddenInputState()
     @updateContentState()
     @updateDecorations()
+    @updateTilesState()
     @updateLinesState()
     @updateCursorsState()
     @updateOverlaysState()
@@ -298,6 +304,30 @@ class TextEditorPresenter
     @state.content.backgroundColor = if @model.isMini() then null else @backgroundColor
     @state.content.placeholderText = if @model.isEmpty() then @model.getPlaceholderText() else null
 
+  updateTilesState: ->
+    return unless @startRow? and @endRow? and @lineHeight?
+
+    linesPerTile = @height / @lineHeight / @tileCount
+
+    startIndex = Math.floor(@startRow / linesPerTile)
+    endIndex = Math.ceil(@endRow / linesPerTile)
+    visibleIndexesRange = [startIndex..endIndex]
+
+    for index, tile of @state.content.tiles
+      unless index in visibleIndexesRange
+        delete @state.content.tiles[index]
+        delete @linesPresentersByTileIndex[index]
+
+    for index in visibleIndexesRange
+      presenter = @linesPresentersByTileIndex[index] ?= new LinesPresenter(@)
+      presenter.startRow = Math.floor(index * linesPerTile)
+      presenter.endRow = Math.ceil(Math.min(@endRow, (index + 1) * linesPerTile))
+      presenter.lineHeight = @lineHeight
+
+      tile = @state.content.tiles[index] ?= {}
+      tile.top = (index * linesPerTile * @lineHeight) - @scrollTop
+      tile.lines = presenter.getState()
+
   updateLinesState: ->
     return unless @startRow? and @endRow? and @lineHeight?