WIP: Start on Renderer, which combines LineWrapper and LineFolder

spec/atom/renderer-spec.coffee

@@ -0,0 +1,69 @@
+Renderer = require 'renderer'
+Buffer = require 'buffer'
+
+describe "Renderer", ->
+  [renderer, buffer] = []
+  beforeEach ->
+    buffer = new Buffer(require.resolve 'fixtures/sample.js')
+    renderer = new Renderer(buffer)
+
+  describe "line rendering", ->
+    fdescribe "soft wrapping", ->
+      beforeEach ->
+        renderer.setMaxLineLength(50)
+
+      describe "when the line is shorter than the max line length", ->
+        it "renders the line unchanged", ->
+          expect(renderer.lineForRow(0).text).toBe buffer.lineForRow(0)
+
+      describe "when the line is empty", ->
+        it "renders the empty line", ->
+          expect(renderer.lineForRow(13).text).toBe ''
+
+      describe "when there is a non-whitespace character at the max length boundary", ->
+        describe "when there is whitespace before the boundary", ->
+          it "wraps the line at the end of the first whitespace preceding the boundary", ->
+            expect(renderer.lineForRow(10).text).toBe '    return '
+            expect(renderer.lineForRow(11).text).toBe 'sort(left).concat(pivot).concat(sort(right));'
+
+        describe "when there is no whitespace before the boundary", ->
+          it "wraps the line exactly at the boundary since there's no more graceful place to wrap it", ->
+            buffer.change([[0, 0], [1, 0]], 'abcdefghijklmnopqrstuvwxyz\n')
+            renderer.setMaxLineLength(10)
+            expect(renderer.lineForRow(0).text).toBe 'abcdefghij'
+            expect(renderer.lineForRow(1).text).toBe 'klmnopqrst'
+            expect(renderer.lineForRow(2).text).toBe 'uvwxyz'
+
+      describe "when there is a whitespace character at the max length boundary", ->
+        it "wraps the line at the first non-whitespace character following the boundary", ->
+          expect(renderer.lineForRow(3).text).toBe '    var pivot = items.shift(), current, left = [], '
+          expect(renderer.lineForRow(4).text).toBe 'right = [];'
+
+      describe "when there is a fold placeholder straddling the max length boundary", ->
+
+    describe "folding", ->
+      describe "when a fold spans multiple lines", ->
+
+      describe "when a fold spans a single line", ->
+
+      describe "when a fold is nested within another fold", ->
+
+      describe "when a fold begins on the line on which another fold ends", ->
+
+      describe "when a fold starts at the beginning of a line", ->
+
+      describe "when a fold ends at the beginning of a line", ->
+
+      describe "when a fold starts on the first line of the buffer", ->
+
+    describe "soft wrapping combined with folding", ->
+      describe "when a line with a fold placeholder is longer than the max line length", ->
+
+
+
+
+
+
+
+
+

src/atom/renderer.coffee

@@ -0,0 +1,49 @@
+Highlighter = require 'highlighter'
+LineMap = require 'line-map'
+Point = require 'point'
+
+module.exports =
+class Renderer
+  lineMap: null
+  highlighter: null
+
+  constructor: (@buffer) ->
+    @highlighter = new Highlighter(@buffer)
+
+  buildLineMap: ->
+    @lineMap = new LineMap
+    @lineMap.insertAtInputRow 0, @buildLinesForBufferRows(0, @buffer.lastRow())
+
+  setMaxLineLength: (@maxLineLength) ->
+    @buildLineMap()
+
+  lineForRow: (row) ->
+    @lineMap.lineForOutputRow(row)
+
+  logLines: ->
+    @lineMap.logLines()
+
+  buildLinesForBufferRows: (startRow, endRow, startColumn=0) ->
+    return [] if startRow > endRow
+
+    line = @highlighter.lineForRow(startRow).splitAt(startColumn)[1]
+    if wrapColumn = @findWrapColumn(line.text)
+      line = line.splitAt(wrapColumn)[0]
+      line.outputDelta = new Point(1, 0)
+      [line].concat @buildLinesForBufferRows(startRow, endRow, startColumn + wrapColumn)
+    else
+      [line].concat @buildLinesForBufferRows(startRow + 1, endRow)
+
+  findWrapColumn: (line) ->
+    return unless line.length > @maxLineLength
+
+    if /\s/.test(line[@maxLineLength])
+      # search forward for the start of a word past the boundary
+      for column in [@maxLineLength..line.length]
+        return column if /\S/.test(line[column])
+      return line.length
+    else
+      # search backward for the start of the word on the boundary
+      for column in [@maxLineLength..0]
+        return column + 1 if /\s/.test(line[column])
+      return @maxLineLength