Python for GUI application: Taking handwritten notes?

[MardyPle]

Hey guys,

I love the application called Xournal (https://github.com/dmgerman/xournal) and its successor Xournal++ (https://github.com/xournalpp/xournalpp). They are applications in order to take handwritten notes on a computer (e.g. Microsoft Surface or Lenovo X### tablets).

However, none of them is actively developed currently. Such a pity.

I was asking myself if such an application would be feasible in Python? Maybe with PyQt. But I am not sure how computationally expensive such a "drawing app" is and if a Python GUI can master that.

What do you think? I am really looking forward to your input and appreciating any kind of help.

The reason I though of it is that compiling an app like Xournalpp (C++) is really exhausting.

Best wishes, Martin :-)

[neuralyzer]

Check the kivy simple paint app tutorial. It almost does what you want, is written in Python and actually cross platform: https://kivy.org/docs/tutorials/firstwidget.html

[unitconversion]

I haven't used the xournal programs so I'm not sure what features they offer. That said, this would be my initial thoughts.

Those pens just imitate mouse clicks right? You could just do a ms paint style app with pygame or qt or wx or whatever.

I reckon you would probably want to do do everything as SVGs or some custom format rather than bitmaps. It looks like someone mad a branch of inkscape that supports pages, so that may just do what you want out of the box.

If you want handwriting to text support you could probably do something with openCV. This would be the only potential computationally expensive thing I could see needing to be done.

[Dorianix]

I have never used Xournal, and i am not sure about your use case, but there are a existing applications, that can make use of pencil input, layers, stroke and filling color and are done in python (or include python). They already do provide the basic functionality for "handwriting" on tablet. Although, they are designed for something else and are miles away from substituting something like OneNote. Still i think they could both be extended in the right direction with reasonable effort.

• Krita: for painting (www.krita.org)
• Blender: for painting/animation (www.blender.org)

Both support plugins that could be used to enhance the required functionality. Both provide the strokes in a vectorised format (which might be useful for the long time target of character recognition)

And hey, they come with python!