Display Configuration
This example will mirror a display running under the X Window System to the matrix panel. Raspberry Pi OS now defaults to the Wayland window system instead of X. In order to use this example, you must configure the Pi 5 to use X for its window system display.
Launch raspi-config with sudo raspi-config.
- Scroll down to Advanced Options and press enter
- Scroll down to Wayland and press enter
- Select the X11 option and press enter
- Press enter for Ok on the dialog confirming the configuration of X11.
- Scroll over to Finish and press enter
- When prompted select Yes to reboot and press enter.
To ensure that the system and any applications running believe that a display exists whether or not an HDMI display is plugged in, there will be a modification to the file /boot/firmware/cmdline.txt that adds a video configuration with the smallest allowed display size.
sudo nano /boot/firmware/cmdline.txt
Scroll to the end of the line by pressing end or holding right arrow for a while.
Press space bar to insert a space at the end of the existing line.
Add the following after the space at the end of the existing line.
video=HDMI-A-1:640x480M@60D
Press Ctrl-S to save the file.
Press Ctrl-X to exit.
Then reboot the Pi for it to take effect
sudo reboot
Run X Display Mirror Example
As always, you need to activate the virtual environment before running the example. If you haven't already, then activate it like this.
source ~/venvs/blinka_venv/bin/activate
Next you can run the xdisplay_mirror.py script. The script accepts several arguments to configure the panels. The first 2 are specific to the xdisplay_mirror.py example.
-
--mirror-region- The region of the display to mirror. x,y,w,h values seperated by commas. If omitted it will mirror the entire screen by default. Example:--mirror-region 0,0,128,128to mirror a 128x128 pixel square of the display at real size on the matrices. -
--x-display- The X display to use. The default is:0. Only needs to be specified if you aren't mirroring the default display. -
--resample-method- The PIL resample method to use when resizing the image to be sent to the panel. Valid values are:nearest,bilinear,lanczos, andbicubic. The default isnearestwhich works best for pixel art style graphics that have been scaled up to fit a larger display. Other methods may look better for different graphics.
The remaining arguments are of the configuration options described on the Initialization Config page. The first two are required.
-
--width- the number of pixels wide the total panel is. 128px is for a 2x2 matrix panel. -
--height- the number of pixels tall the total panel is. 64px is for a 2x2 matrix panel.
The rest are optional if you're using default the configuration for everything.
-
--orientation- the rotation angle, must be one ofNormal,CW,ÂCCW,R180. -
--pinout- the pinout to use for the panel(s) e.g.AdafruitMatrixBonnet -
--num-address-lines- the number of address lines. The 64x64 panels we stock useÂ5, all smaller panels use4 -
--num-planes- the color depth, defaults to10. Lower values can improve refresh rate speed. -
--num-temporal-planes- the temporal dithering control. Valid values are0,2, or4. -
--serpentine- the organization of multiple panels, serpentine is default. Use--no-serpentineif your panels are wired in the non-serpentine configuration.
The values for a 2x2 matrix panel made fro 64x64 matrices rotated 180 are shown below, adjust them for your panel(s).
python xdisplay_mirror.py --pinout AdafruitMatrixHatBGR --width 128 --height 128 --serpentine --num-address-lines 5 --num-planes 8
Once the display is mirrored simply open another terminal or SSH session and launch whatever app you want to mirror.
The code for xdisplay_mirror.py is embedded below. You can download it, or copy/paste the text into a file.
#!/usr/bin/python3
"""
Display a (possibly scaled) X display to a matrix
The display runs until this script exits.
The display doesn't get a keyboard or mouse, so you have to use a program that
will get its input in some other way, such as from a gamepad.
For help with commandline arguments, run `python xdisplay_mirror.py --help`
This example command will mirror the entire display scaled onto a 2x2 grid of 64px panels, total matrix size 128x128.
$ python xdisplay_mirror.py --pinout AdafruitMatrixHatBGR --width 128 --height 128 --serpentine --num-address-lines 5 --num-planes 8
This example command will mirror a 128x128 pixel square from the top left of the display at real size on the same matrix panels
$ python xdisplay_mirror.py --pinout AdafruitMatrixHatBGR --width 128 --height 128 --serpentine --num-address-lines 5 --num-planes 8 --mirror-region 0,0,128,128
"""
import click
import numpy as np
from PIL import Image, ImageEnhance, ImageGrab
import adafruit_blinka_raspberry_pi5_piomatter as piomatter
import adafruit_blinka_raspberry_pi5_piomatter.click as piomatter_click
from adafruit_blinka_raspberry_pi5_piomatter.pixelmappers import simple_multilane_mapper
RESAMPLE_MAP = {
"nearest": Image.NEAREST,
"bilinear": Image.BILINEAR,
"lanczos": Image.LANCZOS,
"bicubic": Image.BICUBIC
}
@click.command
@click.option("--mirror-region", help="Region of X display to mirror. Comma seperated x,y,w,h. "
"Default will mirror entire display.", default="")
@click.option("--x-display", help="The X display to mirror. Default is :0", default=":0")
@click.option("--brightness", help="The brightness factor of the image output to the matrix",
default=1.0, type=click.FloatRange(min=0.1, max=1.0))
@click.option("--resample-method", type=click.Choice(RESAMPLE_MAP), default="nearest",
help="The resample method for PIL to use when resizing the screen image. Default is nearest")
@piomatter_click.standard_options(n_lanes=2, n_temporal_planes=0)
def main(width, height, serpentine, rotation, pinout, n_planes,
n_temporal_planes, n_addr_lines, n_lanes, mirror_region, x_display, resample_method, brightness):
if n_lanes != 2:
pixelmap = simple_multilane_mapper(width, height, n_addr_lines, n_lanes)
geometry = piomatter.Geometry(width=width, height=height, n_planes=n_planes, n_addr_lines=n_addr_lines,
n_temporal_planes=n_temporal_planes, n_lanes=n_lanes, map=pixelmap)
else:
geometry = piomatter.Geometry(width=width, height=height, n_planes=n_planes, n_addr_lines=n_addr_lines,
n_temporal_planes=n_temporal_planes, rotation=rotation, serpentine=serpentine)
framebuffer = np.zeros(shape=(geometry.height, geometry.width, 3), dtype=np.uint8)
matrix = piomatter.PioMatter(colorspace=piomatter.Colorspace.RGB888Packed, pinout=pinout, framebuffer=framebuffer,
geometry=geometry)
if mirror_region:
mirror_region = tuple(int(_) for _ in mirror_region.split(','))
else:
mirror_region = None
size_measure = ImageGrab.grab(xdisplay=":0")
print(f"Mirroring full display: {size_measure.width}, {size_measure.height}")
while True:
img = ImageGrab.grab(xdisplay=x_display)
if mirror_region is not None:
img = img.crop((mirror_region[0], mirror_region[1], # left,top
mirror_region[0] + mirror_region[2], # right
mirror_region[1] + mirror_region[3])) # bottom
if brightness != 1.0:
darkener = ImageEnhance.Brightness(img)
img = darkener.enhance(brightness)
img = img.resize((width, height), RESAMPLE_MAP[resample_method])
framebuffer[:, :] = np.array(img)
matrix.show()
if __name__ == '__main__':
main()
Page last edited March 12, 2025
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