Added sync PNGStream support

lib/canvas.js

@@ -174,6 +174,17 @@ Canvas.prototype.createPNGStream = function(){
   return new PNGStream(this);
 };
 
+/**
+ * Create a synchronous `PNGStream` for `this` canvas.
+ *
+ * @return {PNGStream}
+ * @api public
+ */
+
+Canvas.prototype.createSyncPNGStream = function(){
+  return new PNGStream(this, true);
+};
+
 /**
  * Return a `Buffer` instance consisting of the PNG image data.
  *
@@ -183,7 +194,7 @@ Canvas.prototype.createPNGStream = function(){
 
 Canvas.prototype.toBuffer = function(){
   var buf;
-  this.streamPNG(function(err, chunk, len){
+  this.streamPNGSync(function(err, chunk, len){
     if (err) throw err;
     if (len) {
       buf = buf

lib/pngstream.js

@@ -30,14 +30,19 @@ var EventEmitter = require('events').EventEmitter;
  *     });
  *
  * @param {Canvas} canvas
+ * @param {Boolean} sync
  * @api public
  */
 
-var PNGStream = module.exports = function PNGStream(canvas) {
+var PNGStream = module.exports = function PNGStream(canvas, sync) {
-  var self = this;
+  var self = this
+    , method = sync
+      ? 'streamPNGSync'
+      : 'streamPNG';
+  this.sync = sync;
   this.canvas = canvas;
   process.nextTick(function(){
-    canvas.streamPNG(function(err, chunk, len){
+    canvas[method](function(err, chunk, len){
       if (err) {
         self.emit('error', err);
       } else if (len) {

src/canvas.cc

@@ -31,7 +31,7 @@ Canvas::Initialize(Handle<Object> target) {
   t->InstanceTemplate()->SetInternalFieldCount(1);
   t->SetClassName(String::NewSymbol("Canvas"));
 
-  NODE_SET_PROTOTYPE_METHOD(t, "streamPNG", StreamPNG);
+  NODE_SET_PROTOTYPE_METHOD(t, "streamPNGSync", StreamPNGSync);
   NODE_SET_PROTOTYPE_METHOD(t, "savePNG", SavePNG);
   target->Set(String::NewSymbol("Canvas"), t->GetFunction());
 }
@@ -71,11 +71,11 @@ writeToBuffer(void *c, const uint8_t *data, unsigned len) {
 }
 
 /*
- * Return a node Buffer containing PNG data.
+ * Stream PNG data synchronously.
  */
 
 Handle<Value>
-Canvas::StreamPNG(const Arguments &args) {
+Canvas::StreamPNGSync(const Arguments &args) {
   HandleScope scope;
   // TODO: async
   if (!args[0]->IsFunction())

src/canvas.h

@@ -51,7 +51,7 @@ class Canvas: public node::ObjectWrap {
     static void Initialize(Handle<Object> target);
     static Handle<Value> New(const Arguments &args);
     static Handle<Value> SavePNG(const Arguments &args);
-    static Handle<Value> StreamPNG(const Arguments &args);
+    static Handle<Value> StreamPNGSync(const Arguments &args);
     static Handle<Value> Error(cairo_status_t status);
     inline cairo_surface_t *getSurface(){ return _surface; }
     static void blur(cairo_surface_t *surface, int radius);

test/canvas.test.js

@@ -630,7 +630,7 @@ module.exports = {
     }
     
     var out = fs.createWriteStream(path)
-      , stream = canvas.createPNGStream();
+      , stream = canvas.createSyncPNGStream();
 
     out.on('close', function(){
       assertChecksumOf(