De/Serializing Recordings in Recordable HTML5 Canvas

Last year I blogged about creating a recordable HTML5 Canvas. I explained how to record strokes/drawings created on a HTML5 Canvas and play them back. There are a couple of comments on that post asking me to explain how to save recordings and load them back. Serialization and deserialization of recordings was on my to-do list for a long time and finally this week I got around to implement it. There are different ways to serialize and deserialize recordings, and I have implemented a simple method – using JSON. The serialized data is a bit verbose because of descriptive variable names I have used, but you can change that easily.

RecordableDrawing (in this script file) function remains unchanged. I have added a new file drawingSerializer.js . Two important functions in this file are serializeDrawing and deserializeDrawing.
serializeDrawing takes a RecordableDrawing object as argument and returns JSON string containing array of recordings.
deserializeDrawing takes a String (serialized data) as argument and returns array of Recording objects.

To see how serialization and deserialization works, follow these steps – Continue reading “De/Serializing Recordings in Recordable HTML5 Canvas”

Record and Playback Drawing in HTML5 Canvas

A few months back I had created an application that recorded and played back drawings on HTML5 Canvas. For some time now I wanted to refactor the code in that application and create a reusable ‘component’ from it. Which is what I did this week.

Go ahead and try the demo first – Press ‘Record’ key below and then draw some strokes/lines in the box with the mouse (holding down left button). Once you are done, click Stop button. Click ‘Play’ button to play back the drawing you just drew. You can pause and resume too.

Continue reading “Record and Playback Drawing in HTML5 Canvas”