Begin to lay out a symetric packer api for synchronous usage.

README.md

@@ -245,6 +245,17 @@ var data = fs.readFileSync('in.png');
 var png = PNG.sync.read(data);
 ```
 
+### PNG.sync.write(png)
+
+Take a PNG image and returns a buffer. The properties on the image include the meta data and `data` as per the async API above.
+
+```
+var data = fs.readFileSync('in.png');
+var png = PNG.sync.read(data);
+var buffer = PNG.sync.write(png);
+fs.writeFileSync('out.png', buffer);
+```
+
 ### PNG.adjustGamma(src)
 
 Adjusts the gamma of a sync image. See the async adjustGamma.

examples/sync.js

@@ -0,0 +1,19 @@
+#!/usr/bin/env node
+
+var fs = require('fs'),
+  PNG = require('../lib/png').PNG;
+
+
+var srcFname = process.argv[2],
+  dstFname = process.argv[3] || 'out.png';
+
+// Read a PNG file
+var data = fs.readFileSync(srcFname);
+// Parse it
+var png = PNG.sync.read(data, {
+  filterType: -1
+});
+// Pack it back into a PNG data
+var buff = PNG.sync.write(png);
+// Write a PNG file
+fs.writeFileSync(dstFname, buff);

lib/packer-async.js

@@ -8,7 +8,7 @@ var CrcStream = require('./crc');
 var constants = require('./constants');
 var bitPacker = require('./bitpacker');
 
-var Packer = module.exports = function(options) {
+var PackerAsync = module.exports = function(options) {
   Stream.call(this);
 
   this._options = options;
@@ -30,10 +30,10 @@ var Packer = module.exports = function(options) {
 
   this.readable = true;
 };
-util.inherits(Packer, Stream);
+util.inherits(PackerAsync, Stream);
 
 
-Packer.prototype.pack = function(data, width, height, gamma) {
+PackerAsync.prototype.pack = function(data, width, height, gamma) {
   // Signature
   this.emit('data', new Buffer(constants.PNG_SIGNATURE));
   this.emit('data', this._packIHDR(width, height, this._options.bitDepth, this._options.colorType));
@@ -69,7 +69,7 @@ Packer.prototype.pack = function(data, width, height, gamma) {
   deflate.end(filteredData);
 };
 
-Packer.prototype._packChunk = function(type, data) {
+PackerAsync.prototype._packChunk = function(type, data) {
 
   var len = (data ? data.length : 0);
   var buf = new Buffer(len + 12);
@@ -85,13 +85,13 @@ Packer.prototype._packChunk = function(type, data) {
   return buf;
 };
 
-Packer.prototype._packGAMA = function(gamma) {
+PackerAsync.prototype._packGAMA = function(gamma) {
   var buf = new Buffer(4);
   buf.writeUInt32BE(Math.floor(gamma * constants.GAMMA_DIVISION), 0);
   return this._packChunk(constants.TYPE_gAMA, buf);
 };
 
-Packer.prototype._packIHDR = function(width, height, bitDepth, colorType) {
+PackerAsync.prototype._packIHDR = function(width, height, bitDepth, colorType) {
 
   var buf = new Buffer(13);
   buf.writeUInt32BE(width, 0);
@@ -105,10 +105,10 @@ Packer.prototype._packIHDR = function(width, height, bitDepth, colorType) {
   return this._packChunk(constants.TYPE_IHDR, buf);
 };
 
-Packer.prototype._packIDAT = function(data) {
+PackerAsync.prototype._packIDAT = function(data) {
   return this._packChunk(constants.TYPE_IDAT, data);
 };
 
-Packer.prototype._packIEND = function() {
+PackerAsync.prototype._packIEND = function() {
   return this._packChunk(constants.TYPE_IEND, null);
 };

lib/packer-sync.js

@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = function(buffer, options) {
+  return null;
+};

lib/png-sync.js

@@ -2,9 +2,15 @@
 
 
 var parse = require('./parser-sync');
+var pack = require('./packer-sync');
 
 
 exports.read = function(buffer, options) {
 
   return parse(buffer, options || {});
 };
+
+exports.write = function(png) {
+
+  return pack(png);
+};

lib/png.js

@@ -3,7 +3,7 @@
 var util = require('util');
 var Stream = require('stream');
 var Parser = require('./parser-async');
-var Packer = require('./packer');
+var Packer = require('./packer-async');
 var PNGSync = require('./png-sync');