idotmatrix-api-client 0.2.0

Pixel Display Library

Control all your 16x16 or 32x32 or 64x64 iDotMatrix Pixel Displays

Report Bug or Request Feature

Table Of Contents

• About the Project
• Getting Started
  • Prerequisites
  • Installation
• Usage
• Fonts
• Roadmap
• Contributing
• License
• Authors
• Acknowledgements

About The Project

This repository aims to reverse engineer the iDotMatrix Android App for pixel screen displays like this one on Aliexpress. The goal is to provide a library which can be used to connect and control these displays without the need for the official app.

Getting Started

Prerequisites

Please install the following for your distribution (Windows may work but it is untested):

• latest Python3
• Python3 Virtual Env

Installation

use latest github source code

1. Clone the repo

git clone https://github.com/markusressel/python3-idotmatrix-library.git

2. Install the latest version locally

cd python3-idotmatrix-library/
python3 -m venv venv
source venv/bin/activate  # on Windows use `venv\Scripts\activate`
pip install --upgrade pip poetry
poetry install

Usage

Device API Client

import asyncio

from idotmatrix import IDotMatrixClient, ScreenSize


async def main():
  # create a new IDotMatrixClient instance
  client = IDotMatrixClient(
    # (optional) the screen size of your device, ScreenSize.SIZE_64x64, SIZE_32x32 or SIZE_16x16.
    # If it is left out, the client asks the device when connecting (so call `connect` before using images or GIFs).
    screen_size=ScreenSize.SIZE_64x64,
    # mac_address="00:11:22:33:44:55",  # (optional) specify your device's Bluetooth address
  )
  # (optional) connect to first found iDotMatrix Pixel Display
  # If the device is not connected when issuing commands, an automatic connection attempt will be made.
  await client.connect()

  # do something with the device by using one of the toplevel functions or modules e.g. chronograph, clock, countdown, etc.
  await client.set_brightness(50)  # set brightness to 50%

  await client.text.show_text("Hello World!")  # display text on the screen


if __name__ == "__main__":
  try:
    asyncio.run(main())
  except KeyboardInterrupt:
    quit()

For more examples please check the example.py.

Images and GIFs

from idotmatrix.util.image_utils import ResizeMode

# show a photo or any other image, scaled to the screen
await client.image.show_image_file("photo.jpg", resize_mode=ResizeMode.FILL)

# show an animated GIF
await client.gif.upload_gif_file("animation.gif")

Both can be mixed freely, no mode switching is needed in between. They work like the official app, which waits for the device to acknowledge each chunk of data. An UploadError is raised if the device rejects an upload or does not answer.

client.image.upload_image_file uses the DIY mode instead (see client.image.set_mode), which is meant for drawing pixel by pixel and has to be left again before a GIF can be shown.

Home Assistant and other Bluetooth stacks

A Home Assistant integration that is built on this library is in development: ha-idotmatrix.

By default the library connects with bleak itself. If something else owns the Bluetooth stack, like the scanner and the Bluetooth proxies of Home Assistant, hand over what it found or how to connect:

# a BLEDevice that a scanner found, instead of a MAC address
client = IDotMatrixClient(screen_size=ScreenSize.SIZE_64x64, ble_device=ble_device)

# or provide the whole connection, by implementing `idotmatrix.transport.Transport`
client = IDotMatrixClient(
    screen_size=ScreenSize.SIZE_64x64,
    mac_address="00:11:22:33:44:55",
    transport_factory=lambda address_or_device, on_disconnected: MyTransport(address_or_device, on_disconnected),
)

Turn off install_signal_handlers if your application handles SIGINT and SIGTERM itself, otherwise the client replaces the handlers of the event loop to close the connection on exit. To connect with bleak-retry-connector (Bluetooth proxies), create the transport yourself: BleakTransport(address_or_device, on_disconnected, connector=...) where the connector is an async function that returns a connected BleakClient, like establish_connection.

ConnectionManager.set_device(ble_device) hands over a newer BLEDevice later. An established connection stays, the new one is used for the next connection. A Transport has to write to the device, deliver its notifications and call on_disconnected when the link is lost, see idotmatrix/transport.py and the FakeTransport in tests/ for an example.

Digital Picture Frame

Besides the IDotMatrixClient, this repository also contains a DigitalPictureFrame class which can be used to display images and GIFs in a slideshow fashion. See example_digital_picture_frame.py for more details on how to use it.

The DigitalPictureFrame can

• display a static list of images and/or GIFs
• watch one or more directories for images and GIFs
• automatically reconnect to the device in case of an error or connection loss

Fonts

text.display_text() (and TextModule.show_text()) rasterize each character directly to on/off pixels (1-bit, no anti-aliasing) and send it to the device using one of two fixed per-character cell sizes:

• a compact 8x16 cell, used automatically whenever every character of the string fits within 8px wide / 16px tall
• the full 16x32 cell, used as a fallback for wider/taller glyphs (to avoid clipping)

Because there's no anti-aliasing step, regular vector fonts (the kind designed for print/screen text with serifs, thin strokes, or fine curves) often render with broken strokes, gaps, or lopsided shapes at these tiny sizes - especially once a font's fine details get thresholded straight to black/white. This shows up as visual "artifacts": jagged edges, disconnected letterforms, or an uneven look between different characters of the same font.

Pixel/bitmap-style fonts avoid this problem entirely, since they are designed on a fixed pixel grid to begin with (no fine detail to lose) and render cleanly at any size that's a clean multiple of their native grid.

font_size doesn't grow the per-character cell

The 8x16/16x32 cell picked above is fixed in pixel width (8px or 16px) regardless of the font_size you pass in - font_size only changes how big the glyph is drawn within that fixed cell, it never widens the cell itself. Each character's cell bitmap is then sent back-to-back with no extra spacing added between characters.

This means a font that isn't specifically designed to stay narrow at the font_size you're using will render a glyph that fills (or even overflows) the entire 8px/16px cell width, leaving no blank margin to act as letter-spacing - so consecutive characters end up touching or overlapping. This is why the same font can look perfectly fine at one font_size and become illegible at a larger one: a font's glyph width generally scales with font_size, but the cell width doesn't.

The bundled default (Rain-DRM3.otf) works around this by being intentionally narrow relative to its point size, so it still leaves a gap even at larger sizes. Most other fonts need a specific, manually-verified font_size to look right - see the naming convention below.

Bundled fonts

The idotmatrix/fonts/ directory is part of the installed package and ships a selection of pixel/bitmap fonts (with their respective license files) that have been verified to render cleanly. Each filename (other than the default) is prefixed with the font_size value(s) it has been manually tested and confirmed to render with legible spacing between characters - always pass a matching font_size, since (per above) using a larger one than the font was designed for will make characters touch/overlap:

Pick whichever fits your desired look, but stick to the recommended font_size(s) listed above (or your own tested size) for that font - otherwise characters may run into each other. Narrower fonts (that fit within 8px wide per character at the size used) will also get tighter, more compact text since they qualify for the 8x16 cell instead of the 16x32 one.

Font licenses

Each font keeps its own license, shipped next to it in idotmatrix/fonts/. They do not change the license of this library's code.

The two CC BY-SA fonts are redistributed unmodified. Copies of derived fonts must be shared under the same license, with attribution to the original authors (see the links above).

Finding more fonts

When looking for additional fonts, search for:

• pixel font / bitmap font
• 8x8 font, 5x7 font, dot matrix font
• LED font / LCD font
• retro pixel font / monospace pixel font

Good sources: dafont.com/bitmap.php, fontspace.com's pixel-fonts tag

Always test a new font at the font size you intend to use before committing to it - some pixel-style fonts are only pixel-perfect at their native design size and look uneven at others. Check each font's license before bundling/redistributing it (see the existing *-License.txt files next to each font in idotmatrix/fonts/ for examples).

Roadmap

If you want to contribute please focus on the reverse-engineering part because my personal skills are not that good. Many thanks for all contributions! If you want to dive deep into other issues please check for "#TODO" comments in the source code as well.

• Reverse Engineering
  • Chronograph
  • Clock
  • Countdown
  • Graffiti Board
  • DIY-Mode
  • Animated Images
  • Display Text
  • Alarm & Buzzer (available according to issue #18)
  • Cloud-API to download images
  • Cloud-API to upload images to device
  • Cloud-Firmware Update possible?
  • Eco-Mode
  • Fullscreen Color
  • MusicSync (with the microphone of the device)
  • Scoreboard
  • bluetooth password protection
  • understand the returned byte arrays of the device for better error logs (done for the upload acknowledgements, see the protocol notes in AGENTS.md)

Helpful Links

• Create Images or GIFs
  • pixilart
    • Create a new drawing and select a preset for the size of your display (e.g. 64x64)

Other Hardware

This software is specifically built for devices which are supported by the iDotMatrix app. There are other devices being sold which have a similar form factor and claim to be compatible, but which are not. Below is a list of known non-iDotMatrix-compatible hardware and associated software.

• For hardware supported by the "LOY SPACE" app: https://github.com/eskibars/popledder/

Contributing

Contributions are what make the open source community such an amazing place to be learn, inspire, and create. Any contributions you make are greatly appreciated.

• If you have suggestions for adding or removing projects, feel free to open an issue to discuss it, or directly create a pull request after you edit the README.md file with necessary changes.
• Please make sure you check your spelling and grammar.
• Create individual PR for each suggestion.
• Please also read through the Code Of Conduct before posting your first idea as well.

Creating A Pull Request

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

Distributed under the GNU GENERAL PUBLIC License. See LICENSE for more information.

Acknowledgements

Original project by derkalle4 and jmgraeffe.

• Othneil Drew - README Template
• LordRippon - Reverse Engineering for the Displays
• 8none1 - Reverse Engineering for the Displays
• schorsch3000 - smaller fixes
• tekka007 - code refactoring and reverse engineering
• inselberg - Reverse Engineering for the Displays