Ken Van Hoeylandt
db48dfe812
- Standardized keyboard input using Unicode-based key codes across supported devices and the simulator. Keyboards don't emit `LV_KEY_*` anymore. - Refactored lilygo encoder driver into a reusable GPIO rotary encoder driver (see `Drivers/gpio-encoder-module/`). Added more features to the config file. - Improved LVGL keyboard device management, including duplicate prevention and reliable reconnects. - LVGL file mutex now registers with lvgl start/stop - Improved LVGL startup/shutdown stability and memory allocation reliability. - Increased simulator LVGL memory capacity and improved USB device-class handling.
68 lines
2.6 KiB
Markdown
68 lines
2.6 KiB
Markdown
# lvgl-module
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This module manages the lifecycle of the [LVGL](https://lvgl.io/) library within the Tactility ecosystem.
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## What the library does
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The `lvgl-module` provides:
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- **Lifecycle Management**: Handles initialization and termination of the LVGL library.
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- **Task Management**: Manages the LVGL main loop task.
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- **Thread-Safety**: Provides mutex-based locking mechanisms (`lvgl_lock`, `lvgl_unlock`) to ensure safe access to LVGL APIs from multiple tasks.
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- **Font Access**: Provides a unified interface to access pre-configured text and icon fonts.
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## Different types of fonts
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The module supports two main categories of fonts:
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### Text Fonts
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Standard text rendering uses the **Montserrat** font. Three sizes are pre-configured:
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- `FONT_SIZE_SMALL`
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- `FONT_SIZE_DEFAULT`
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- `FONT_SIZE_LARGE`
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### Icon Fonts
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Icons are provided by the **Material Symbols** font, divided into three usage-specific sets:
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- **Statusbar Icons**: Optimized for the system status bar.
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- **Launcher Icons**: Sized for application launchers.
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- **Shared Icons**: General purpose icons used across the system.
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## How to update the fonts
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Font sizes and symbols are configurable:
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- **On ESP32 (IDF)**: Sizes can be updated via `menuconfig` or by editing `sdkconfig`. Look for `CONFIG_TT_LVGL_FONT_SIZE_*` and `CONFIG_TT_LVGL_*_ICON_SIZE` parameters.
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- **On Simulator/POSIX**: Default sizes are defined in `Modules/lvgl-module/CMakeLists.txt`.
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If you change an icon font size, ensure that a corresponding C file exists in `source-fonts/` (e.g., `material_symbols_shared_24.c`). These files are generated from TTF/OTF fonts using the LVGL font converter.
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## Custom memory allocator
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LVGL's malloc/realloc/free can be routed through a custom backend instead of its built-in pool or
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plain `malloc`. Three things are required:
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**1. Select the backend.** On ESP32, via Kconfig (`sdkconfig`):
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```sdkconfig
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CONFIG_LV_USE_CUSTOM_MALLOC=y
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```
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On Simulator/POSIX, ESP-IDF's Kconfig doesn't apply - select it in `lv_conf.h` instead:
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```c
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#define LV_USE_STDLIB_MALLOC LV_STDLIB_CUSTOM
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```
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**2. Force the module into the link.** LVGL's own init code calls back into the functions above
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a reverse reference a normal single-pass static-archive link can't resolve on its own:
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```cmake
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tactility_add_module(lvgl-module
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...
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WHOLE_ARCHIVE
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)
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```
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Without `WHOLE_ARCHIVE`, or without step 1 selecting the custom backend, ESP-IDF's LVGL component
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compiles its own allocator using these same symbol names - whichever one the linker happens to
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pull in first silently wins, with no error and no guarantee it's the intended one.
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## License
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This module is licensed under the [Apache v2.0](LICENSE-Apache-2.0.md) license. |