Week 1: Vispy/experimental - Proof of Concepts

Hello reader,
       
This is my first post since the GSoC results were declared and I have so much to say!

If you are reading this post and have no idea what I am talking about, you should read my first two posts: Hello GSoC and First Contribution to Vispy.

In the past weeks, my PR against Vispy/experimental has been merged and after some discussion with Vispy-devs, I have to make a new one.

Like I said before in my previous post, I tried to implement the interactivity part on the browser. For this purpose, I chose two of Vispy demos: "rain.py" and "hex-grid.py". The work was to listen mouse events via JavaScript and send them to Vispy using WebSocket. Since this was just a proof of concept, I have dealt with only "mousemove", "mouseup" and "mousedown" events:

rain.py on the browser

After this proof of concept also went well, we agreed that we should go to the next level and discuss the design part with IPython-devs. The main reason behind this was to use IPython 2.0's interactive widgets for the IPython notebook. So, the final decision was to have an architecture integrated nicely with the IPython notebook; but it should *also* work without IPython.

After discussing with the IPython-devs on their mailing list, we learned two things:

1- Jason Grout has some interesting work in this direction.

2- The IPython-devs recommend we use the widgets machinery (based on backbone.js and MVC) instead of going lower-level with WebSockets, JSON, Tornado, Comms, etc.

So, we needed to revisit completely the current approach. The good news was, it should be much simpler as some of the architecture is already implemented in IPython 2.0.

Now, the final idea is to create a widget with a string trait attribute that would contain the base64-encoded PNG representation of the image, and  another structure that would contain user actions (mouse position, click, key_press, etc.).
Those are automatically synchronized between Python and Javascript in real-time in the IPython widgets.

I have started to make another proof of concept on IPython notebook. I have to say that IPython-devs made an excellent work. You should definitely try IPython widgets if you haven't yet.

Next stop: Proof of concept with IPython notebook!
See you soon ;)