I took my first shot at porting and publishing a library to the Web IDE.
It’s based on the Adafruit library for this 3.5" TFT display and requires @peekay123 's awesome Adafruit_mfGFX port.
Since the the display comes with a 4-wire touchscreen I’ve ported and tweaked the original Adafruit lib along with it.
The two libraries are available on Web IDE as Adafruit_HX8357 and Touch_4Wire.
I know there was a port of the HX8357 library in this thread, but since I couldn’t find it in the Web IDE libs, I just got a shot at it.
If anybody has got any hints and suggestions how to improve this - I want to improve anytime 
This pic shows the combined examples for SD-Card-Bitmap display and Touch-Paint.
(not to see on the pic - the Core RGB-LED reflects the selected painting colour)
