1 files changed, 88 insertions, 0 deletions
diff --git a/gif-encode/worker.js b/gif-encode/worker.js
new file mode 100644
index 0000000..b2f32d4
--- /dev/null
+++ b/gif-encode/worker.js
@@ -0,0 +1,88 @@
+importScripts('LZWEncoder.js', 'NeuQuant.js', 'GIFEncoder.js');
+
+self.onmessage = function(event) {
+	var data = event.data;
+	var task = data['task'];
+	switch (task) {
+		case 'encode':
+			encode (data);
+			break;
+		case 'quantize':
+			quantize(data);
+			break;
+	}
+}
+
+function log(msg) {
+  self.postMessage({
+  	task: 'message',
+		message: msg
+	});
+}
+
+function quantize (data) {
+  var imageData = data["imageData"];
+	var pixels = discardAlphaChannel( imageData.data );
+
+	var nq = new NeuQuant (pixels, pixels.length, 1);
+	var colortab = nq.process();
+
+  self.postMessage({
+  	task: 'quantize',
+		neuquant: nq.save(),
+		colortab: colortab
+	});
+}
+
+function discardAlphaChannel( imageData ) {
+	var pixels = [];
+
+	for ( var i = 0, b = 0, _len = imageData.length; i < _len; b += 4 ) {
+		pixels[i++] = imageData[b];
+		pixels[i++] = imageData[b+1];
+		pixels[i++] = imageData[b+2];
+	}
+	return pixels;
+}
+
+function encode (data) {
+  var frame_index = data["frame_index"];
+  var frame_length = data["frame_length"];
+  var height = data["height"];
+  var width = data["width"];
+  var imageData = data["imageData"];
+  var delay = data["delay"];
+  var neuquant = data["neuquant"];
+  var colortab = data["colortab"];
+
+  // Create a new GIFEncoder for every new worker
+  var encoder = new GIFEncoder();
+  encoder.setRepeat(0); 	// loop forever
+  encoder.setQuality(1);
+  encoder.setSize(width, height);
+  encoder.setDelay(delay);
+
+  if (frame_index == 0) {
+    encoder.start();
+  }
+  else {
+    encoder.cont();
+    encoder.setProperties(true, false); //started, firstFrame
+  }
+
+	// Load the neural net here because the color table gets clobbered by encoder.start();
+  encoder.setNeuquant(neuquant, colortab);
+  encoder.addFrame(imageData, true);
+
+  if(frame_length == frame_index) {
+    encoder.finish();
+  }
+
+  self.postMessage({
+  	task: 'encode',
+		frame_index: frame_index,
+		frame_data: encoder.stream().getData()
+	});
+	// on the page, search for the GIF89a to see the frame_index
+};
+