Official touchscreen questions

Question

I'm a French web developer so forgive my Englush

I'm currently working on yet another in-car embedded Raspberry Pi project. I plan to build the software as a Chromium kiosk web app, served by a Node.js process. As a user input, I would like to use the official touchscreen,but before ordering it, I have a few questions about this display.

Does the screen (or software using it) implement natural touch scrolling as on tablets and phones ?

I've been watching some videos about the screen to see that point, but I couldn't..

Also, instead of using a virtual keyboard, I may use handwriting and OCR as text input, I think I could handle it with some JS libs . So my second question is : are touch gestures supported for canvas drawing into the Chromium browser ?

I'd like to watch a few videos about these issues, if one of you do have ones.

I may show you later the wiring diagram of my project, maybe one of you could give me some advice.

I thank you for reading.

Bye

Answer 1

The "offical" Raspberry Pi 7" touchscreen is an USB-HID 10-point capacitive one. It's supported by the standard Linux multitouch input device driver. This driver supports multiple simultaneous touches, but it only reports raw touch points, not "cooked" gestures.

All touchscreens using this standard input driver behave the same. There are some other drivers, mostly for touchscreens connected through I²C or RS232, but as USB-HID sets the standard, they pretty much generate just the same events.

The X11 system traditionally only supports a pointing device with one single point of action. Standard X11 applications will only expect a mouse and don't make use of the multitouch extension X11 offers.

Fortunately, Chrome does. See this question and its answers.

For Chromium, you might need to tweak it a bit.