More work towards channel images

examples/node/export_layers.js

+var PSD = require('../../');
+
+var file = process.argv[2] || './examples/images/example.psd';
+var start = new Date();
+
+PSD.open(file).then(function (psd) {
+  return psd.tree().descendants().forEach(function (node) {
+    if (node.isGroup()) return true;
+    return node.layer.image.saveAsPng("./output/#{node.name}.png");
+  });
+}).then(function () {
+  console.log("Finished in " + ((new Date()) - start) + "ms");
+});;

lib/psd/channel_image.coffee

 _           = require 'lodash'
 Image       = require './image.coffee'
+ImageFormat = require './image_format.coffee'
 
 module.exports = class ChannelImage extends Image
+  @includes ImageFormat.LayerRAW
+  @includes ImageFormat.LayerRLE
 
   constructor: (file, header, @layer) ->
-    @width = @layer.width
-    @height = @layer.height
-
     super(file, header)
 
     @channelsInfo = @layer.channelsInfo
@@ -18,6 +18,8 @@ module.exports = class ChannelImage extends Image
     for chan in @channelsInfo
       @file.seek chan.length, true
 
+  width: -> @layer.width
+  height: -> @layer.height
   channels: -> @layer.channels
 
   parse: ->

lib/psd/image_format.coffee

 module.exports =
   RAW: require('./image_formats/raw.coffee')
   RLE: require('./image_formats/rle.coffee')
+  LayerRLE: require('./image_formats/layer_rle.coffee')
+  LayerRAW: require('./image_formats/layer_raw.coffee')

lib/psd/image_formats/layer_raw.coffee

+module.exports =
+  parseRaw: ->
+    for i in [@chanPos...(@chanPos + @chan.length - 2)]
+      @channelData[i] = @file.readByte()
+
+    @chanPos += (@chan.length - 2)

lib/psd/image_formats/layer_rle.coffee

+module.exports =
+  parseByteCounts: ->
+    @file.readShort() for i in [0...@height()]
+
+  parseChannelData: ->
+    @lineIndex = 0
+    @decodeRLEChannel()

lib/psd/layer/channel_image.coffee

 ChannelImage = require '../channel_image.coffee'
+LazyExecute  = require '../lazy_execute.coffee'
 
 module.exports =
   parseChannelImage: ->

lib/psd/node.coffee

@@ -4,6 +4,7 @@ _        = require 'lodash'
 module.exports = class Node extends Module
   @includes require('./nodes/ancestry.coffee')
   @includes require('./nodes/search.coffee')
+  # @includes require('./nodes/build_preview.coffee')
 
   @PROPERTIES: ['name', 'left', 'right', 'top', 'bottom', 'height', 'width']