Setting up the Display
We will be using the board.DISPLAY option so that we have a lot of control over the way our UI is rendered, like screen orientation as well as the ability to turn elements of our UI on or off.
To use board.DISPLAY, you will need the following code in your CircuitPython program.
display = board.DISPLAY
For this project we are using board.DISPLAY so that all of the critical display settings are loaded for the CircuitPython device we are using. In this case, we are loading the configuration setup for the PyPortal into displayio.Display().
Aside from the main display setup we have a lot of options that we can now set. The two main options we will look at are rotation and backlight.
Screen Rotation
This will let you change the orientation of the display in increments of 90°. So you can also do a user interface in portrait or landscape mode.
To do this, use the following code.
display = board.DISPLAY display.rotation=270
Rendering the Display
Eventually, we will want to have the screen display the content, and to do that we will use the following command:
board.DISPLAY.root_group = splash
This will set a Group named splash as the source of information to be displayed. We will get into Groups on the next section.
The Backlight
You can also adjust the brightness of the display backlight using board.DISPLAY. This simple function will allow you to change the brightness easily.
# Backlight function
# Value between 0 and 1 where 0 is OFF, 0.5 is 50% and 1 is 100% brightness.
def set_backlight(val):
val = max(0, min(1.0, val))
board.DISPLAY.auto_brightness = False
board.DISPLAY.brightness = val
Just use set_backlight(0.3) to set the backlight to 30% brightness.
If you want to see more stuff that you can do with displayio.Display() have a look at the Display section of CircuitPython docs.
The Touchscreen
The PyPortal has a built-in resistive touchscreen that we will use for button navigation in our UI. The following code will set up the basic touchscreen.
# Touchscreen setup
# ------Rotate 270:
screen_width = 240
screen_height = 320
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_XL, board.TOUCH_XR,
board.TOUCH_YD, board.TOUCH_YU,
calibration=((5200, 59000), (5800, 57000)),
size=(screen_width, screen_height))
Rotating the Touchscreen
One issue that we will run into if we rotate the Display for the PyPortal is that this will change the orientation of the display, but the touchscreen coordinates remain the same. Since we will be using the touch screen to detect button presses this is a big issue. Thankfully, we can change the way the touchscreen reads its coordinates by moving the x1_pin, x2_pin, y1_pin, and y2_pin around in addition to switching the size x and y to go from horizontal to vertical format.
To save you some time, here are the touchscreen settings you will want to use if the screen is rotated 0°, 90°, 180°, or 270°
# -------Rotate 0:
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_XL, board.TOUCH_XR,
board.TOUCH_YD, board.TOUCH_YU,
calibration=((5200, 59000), (5800, 57000)),
size=(320, 240))
# -------Rotate 90:
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_YU, board.TOUCH_YD,
board.TOUCH_XL, board.TOUCH_XR,
calibration=((5200, 59000), (5800, 57000)),
size=(240, 320))
# ------Rotate 180:
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_XR, board.TOUCH_XL,
board.TOUCH_YU, board.TOUCH_YD,
calibration=((5200, 59000), (5800, 57000)),
size=(320, 240))
# ------Rotate 270:
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_YD, board.TOUCH_YU,
board.TOUCH_XR, board.TOUCH_XL,
calibration=((5200, 59000), (5800, 57000)),
size=(240, 320))
Just replace the touchscreen settings with whatever ones you would like to use.
Here is the code you would need to set the PyPortal up in 270° orientation.
pyportal = PyPortal()
display = board.DISPLAY
display.rotation = 270
# Touchscreen setup
# ------Rotate 270:
screen_width = 240
screen_height = 320
ts = adafruit_touchscreen.Touchscreen(board.TOUCH_YD, board.TOUCH_YU,
board.TOUCH_XR, board.TOUCH_XL,
calibration=((5200, 59000),
(5800, 57000)),
size=(screen_width, screen_height))
Note that we have added PyPortal to the project even though we are not using it for Display, there are some other things that we will use it for later.
For more information about Touchscreen, click the button below.
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