Creating a user interface that accepts sketch input

I would like to create a simple application asks the user to draw an image they have been shown. Once the user has completed the image the program would score the drawing. Are there any existing libraries for creating interfaces that accept sketches/drawing from users? I need a sketch object (maybe as a vector gra开发者_如何学Cph) which can be processed.

The program should run on tablets and touch screen laptops, preferably on windows however multi-platform would be ideal. I am open to using what ever programming language is best for this project.

Currently I am looking at the SATIN library (http://dub.washington.edu:2007/projects/satin/) but it is rather old, the last change was in 2001.

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Maybe you can try Pencil. It's a add-ons for firefox and you can easily draw some sketch schema (or mockup).

Download Pencil for Firefox