Completed implementation of basic dynamic encoder

index.js

@@ -173,17 +173,23 @@ PNGImage.loadImage = function (blob, fn) {
  * @return {PNGImage}
  */
 PNGImage.loadImageSync = function (blob) {
-	var decoder = new Decoder(blob, false);
-	var result = decoder.decode();
-	var headerChunk = decoder.getHeaderChunk();
-	var width = headerChunk.getWidth();
-	var height = headerChunk.getHeight();
+	var decoder,
+		data,
+		headerChunk,
+		width, height;
+
+	decoder = new Decoder();
+	data = decoder.decode(blob, { strict: false });
+
+	headerChunk = decoder.getHeaderChunk();
+	width = headerChunk.getWidth();
+	height = headerChunk.getHeight();
 
 	var image = new PNG({
 		width: width,
 		height: height
 	});
-	result.copy(image.data, 0, 0, result.length);
+	data.copy(image.data, 0, 0, data.length);
 	return new PNGImage(image);
 };
 
@@ -398,10 +404,9 @@ PNGImage.prototype = {
 		fs.writeFileSync(filename, this.toBlobSync());
 	},
 
-	toBlobSync: function () {
-		var encoder = new Encoder(this.getWidth(), this.getHeight(), this.getBlob(), 0);
-
-		return encoder.encode();
+	toBlobSync: function (options) {
+		var encoder = new Encoder();
+		return encoder.encode(this.getBlob(), this.getWidth(), this.getHeight(), options);
 	},
 
 	/**

lib/png/chunk.js

@@ -34,19 +34,6 @@ Chunk.prototype.getType = function () {
 	return null;
 };
 
-/**
- * Gets the chunk-type as id
- *
- * Note:
- * This is the numeric version of `getType`.
- *
- * @method getTypeId
- * @return {int}
- */
-Chunk.prototype.getTypeId = function () {
-	return 0;
-};
-
 /**
  * Gets the sequence
  *
@@ -394,6 +381,27 @@ Chunk.getChunkType = function (type) {
 	return this._registry[type];
 };
 
+/**
+ * Gets a list of registered chunk types
+ *
+ * @static
+ * @method getChunkTypes
+ * @return {string[]}
+ */
+Chunk.getChunkTypes = function () {
+
+	var result = [],
+		i;
+
+	for (i in this._registry) {
+		if (this._registry.hasOwnProperty(i)) {
+			result.push(i);
+		}
+	}
+
+	return result;
+};
+
 /**
  * Applies the chunk-module on an object
  *

lib/png/chunks/IHDR.js

@@ -690,7 +690,7 @@ module.exports = {
 		stream.writeUInt8(this.getBitDepth());
 		stream.writeUInt8(this.getColorType());
 		stream.writeUInt8(this.getCompressionMethod());
-		stream.writeUInt8(this.getFilterMethod);
+		stream.writeUInt8(this.getFilterMethod());
 		stream.writeUInt8(this.getInterlaceMethod());
 	},
 
@@ -714,6 +714,7 @@ module.exports = {
 			lastChunkLength, i;
 
 		for (i = 0; i < chunkQuantity; i++) {
+
 			chunk = new Chunk('IDAT', this._chunks);
 
 			lastChunkLength = Math.min(stream.length, chunkLength);

lib/png/decoder.js

@@ -17,14 +17,9 @@ var path = require('path');
  * @module PNG
  * @submodule PNGCore
  * @extends chunkUtils
- * @param {Buffer} data Data to decode
- * @param {int} [offset=0] Offset within data
- * @param {int} [length=data.length-offset] Length of data
  * @constructor
  */
-var Decoder = function (data, offset, length) {
-	this._stream = new BufferedStream(data, offset, length);
-
+var Decoder = function () {
 	this._chunks = {};
 	this._chunkData = {};
 
@@ -48,7 +43,8 @@ Decoder.prototype.getChunkData = function () {
  *
  * @method decode
  * @param {Buffer} data Image data
- * @param {object} options Decoding options
+ * @param {object} [options] Decoding options
+ * @param {boolean} [options.strict=false] Strict decoding
  */
 Decoder.prototype.decode = function (data, options) {
 
@@ -72,13 +68,13 @@ Decoder.prototype.decode = function (data, options) {
 	}
 
 	// Load all chunks until end is reached
-	// Phase 1
+	// Phase 1 - Forward
 	do {
 		chunk = this._parseChunk(stream, strict);
 	} while (chunk.getType() !== 'IEND');
 
 	// Run through all chunks before scaling
-	// Phase 2
+	// Phase 2 - Forward
 	this.applyWithSortedChunks(function (chunk) {
 
 		try {
@@ -95,7 +91,7 @@ Decoder.prototype.decode = function (data, options) {
 	}, true);
 
 	// Run through all chunks after scaling
-	// Phase 3
+	// Phase 3 - Forward
 	this.applyWithSortedChunks(function (chunk) {
 
 		try {
@@ -112,7 +108,7 @@ Decoder.prototype.decode = function (data, options) {
 	}, true);
 
 	// Run through all chunks-types (not chunks) to gather chunk-data
-	// Phase 4
+	// Phase 4 - Forward
 	this.applyWithSortedChunks(function (chunk) {
 		Chunk.decodeTypeData(chunk.getType(), this._chunkData, this._chunks, strict);
 	}.bind(this), false);
@@ -134,6 +130,7 @@ Decoder.prototype._parseChunk = function (stream, strict) {
 	var chunkLength,
 		chunkType,
 		chunkCrc,
+		calculatedCrc,
 		crc,
 		chunk,
 		chunkOffset;
@@ -157,7 +154,8 @@ Decoder.prototype._parseChunk = function (stream, strict) {
 
 		// Load crc and compare with calculated one
 		chunkCrc = stream.readInt32BE();
-		if (strict && (chunkCrc !== crc.getValue())) {
+		calculatedCrc = crc.getValue();
+		if (strict && (chunkCrc !== calculatedCrc)) {
 			throw new Error('CRC error.');
 		}