Add support for Waveshare 5.83

[garytube]

https://www.waveshare.com/wiki/5.83inch_e-Paper_HAT

I will try to add support myself but i would grateful for any tipps & gotchas

[samsonmking]

@garytube glad to have you on board!

• The basic idea is that for each screen there is a c++ file that takes the provided Waveshare c drivers and exposes them as a node module using the node.js n-api. As you might be aware, this is how node lets you drop to c / c++ for higher performance / access to system APIs. For the 4.2" display, this file is EPD_4in2_node.cc.
• There's a build tool called gyp that compiles the c++ file, along with any dependencies. This is configured with the binding.gyp file and referenced as a build step (that occurs automatically when you install epaper.js) inside package.json.
• The devices.js file imports the c++ driver from the steps above and binds it to a common interface. So each device has an init and displayPNG method. These devices are also the objects the user specifies, when they specify which screen they'd like to use.
• You'll notice inside the device.displayPNG method references to other methods like convertPNGTo4Grey(). The HTML / JS contents that you display on the screen are rendered as a color PNG, which displayPNG consumes and converts into a format the display can understand. Usually this logic is ported from the example Waveshare c or python code to JavaScript. Looking at the example Waveshare file epd5in83_V2.py I believe you may be able to use the existing convertPNGto1BitBW and convertPNGto1BitBWRotated methods in image.js.

That's a quick overview, please reach out if you have any questions, and I'd be happy to help!

[abhayakulkarni]

This is such a nice explanation,Thank you.

[samsonmking]

@abhayakulkarni, the process has changed a little since the release of version 2.0. I'll work on writing up some documentation, soon.