Kivy and 3.5PiTFT

Question

I have written an application with Kivy that I want to run on my raspberry pi. I have a model 2 pi, a 3.5 inch PiTFT. I am connected via HDMI to an external screen. I followed the instructions for installing kivy on the pi, and I am trying to run the examples.

Firstly, with the console on the piTFT when I run kivy/examples/demo/kivycatalog main.py the application is automatically output to my external HDMI screen. However, the image seems to be very bad compared to when I run the exact same application on my mac. Why might this happen?

Secondly I am unable to get the application to display on my piTFT.

I tried KIVY_BCM_DISPMANX_ID=3 python main.py as I believe that my piTFT has an id of 3 (although I cannot remember how to check this).

Has anyone successfully run any of the kivy demos on their piTFT?

My pi runs on Debian

Answer 1

I just got it working under the Adafruit Raspbian Jessie image (although I am still fiddling with an inverted x/y touchscreen issue).

The secret seems to be:

1) do the detailed install outlined here:

https://github.com/mrichardson23/rpi-kivy-screen

When you edit the file ~/.kivy/config.ini per those instrucitons, also edit the [DISPLAY] section to set the display size to 320x240

2) you also have to run** fbcp while you are running kivy

see https://github.com/tasanakorn/rpi-fbcp

To install that you will probably need to install cmake:

sudo apt-get install cmake

Once I did those steps the examples ran.

** E.g., in one SSH terminal window I run

$ path_to_where_compiled_fbcp/fbcp

then in another SSH terminal window I run

$ python examples/demo/pictures/main.py

If you run into problems where the RESISTIVE touch screen coordinates seem reversed, try this in your ~/.kivy/config.ini file (which also needs to be copied to /root/ using sudo cp)

[input]
mouse = mouse
mtdev_%(name)s = probesysfs,provider=mtdev
hid_%(name)s = probesysfs,provider=hidinput,param=rotation=270,param=invert_y=1

Note: if you are using the CAPACITIVE touch screen, the code is a bit different to use mtdev due to some sort of bug with the hidinput system for PiTFT:

[input]
mouse = mouse
%(name)s = probesysfs,provider=hidinput
pitft = mtdev,/dev/input/touchscreen,max_position_x=240,max_position_y=320,invert_y=0,invert_x=1,rotation=270

Answer 2

Adding some updated info. I am trying this in July 2019, and I was able to get the screen displaying and responding to touch inputs by following the 'easy install' instructions from Adafruit

The remaining part I was missing to get Kivy touch inputs to line up with the screen orientation I was able to figure out from the previous answer.

[input]
mouse = mouse
hid_%(name)s = probesysfs,provider=hidinput,param=rotation=90,param=invert_y=1

I needed to use 'rotation=90' which matches what I entered in the AdaFruit easy-setup wizard.