[if you want to support p44lrgraphics development, consider to sponsor plan44]
p44lrgraphics is a set of free (opensource, GPLv3) C++ classes and functions building a graphics library specially targeted at low resolution displays.
A low resolution display is usually a LED matrix of a few 100 to 1000 LEDs, meaning a total pixel count in the 1000s range.
Even the smallest TFT displays start in the 100'000 pixel range, and any computer screen nowadays has millions of pixels. So, clearly, p44lrgraphics is not meant a generic graphics library (if you are looking for a small one suitable for embedded devices, I can recommend LittlevGL), which is also supported via p44utils.
p44lrgraphics's view structure is similar to other framework's. However the implementation is mostly done following the needs of driving LED chains and matrices, in particular those of the WS281x variety.
One main design decision that only makes sense for a modest number of pixels but quickly changing imagery (light effects) is that p44lrgraphics is not focused on drawing things into image buffers and then flattening those down the view/layer hierarchy to a full screen image, displayed at a fixed frame rate.
Instead, p44lrgraphics mostly does exactly the opposite: each of the (relatively few) pixels asks from bottom up the view hierarchy for its current color, and the views then calculate the pixels on demand. This simplifies the code in many cases, and because of the relatively few pixels involved, it does not need a lot of performance. And it allows asynchronous updating timed to other events than those of a fixed frame rate.
p44lrgraphics needs some classes and functions from the p44utils library.
Projects using p44lrgraphics (or cointaining roots that led to it) include the pixelboard, the ETH digital platform, and the "chatty wifi" installation I brought to the 35c3 (which is in the hermel branch of lethd)
To create pixel fonts for p44lrgraphics, the Q&D macOS app FontHexer2 can be used to sample existing pixel-ready fonts. A few of these are included in the font/ subfolder of this repo already.
p44lrgraphics sources meant to be included as .cpp and .hpp files into a project (usually as a git submodule) and compiled together with the project's other sources.
A configuration header file p44lrg_config.hpp needs to be present in the project, and allows customizing some aspects of p44lrgraphics.
To get started, just copy the p44lrg_config_TEMPLATE.hpp to a location in your include path and name it p44lrg_config.hpp.
p44lrgraphics is licensed under the GPLv3 License (see COPYING).
If that's a problem for your particular application, I am open to provide a commercial license, please contact me at luz@plan44.ch.
Details tbd. but quick list for now:
- views with 90 degree rotation, mirroring
- scrolling with subpixel resolution (antialiasing)
- png image views
- view stacks
- view animations
- Support for Microsofts expressive pixels IoT animation format with the "epx" view
- on the fly reconfiguration via JSON API/config files
- extensive p44script support.
- use it!
- support development via github sponsors or flattr
- Discuss it in the plan44 community forum.
- contribute patches, report issues and suggest new functionality on github or in the forum.
- Buy plan44.ch products - sales revenue is paying the time for contributing to opensource projects :-)
(c) 2013-2022 by Lukas Zeller / plan44.ch