lv_conf.h¶

LVGL v9.2.2 configuration header tailored for the Asuro bare-metal kernel environment.

Overview¶

This file configures the LVGL graphics library for use inside the Asuro kernel, where no standard C library, operating system, or GPU hardware is available. It selects a 32-bit XRGB8888 color depth to match the VESA framebuffer, routes all stdlib functionality through LVGL's built-in implementations, enables only the software renderer, and disables every hardware backend, filesystem driver, and image decoder. The result is a minimal but functional GUI stack that runs entirely in kernel space.

Configuration Options / Defines¶

Color Settings¶

LV_COLOR_DEPTH¶

Value: 32. Matches the VESA XRGB8888 framebuffer used by Asuro.

Standard Library Wrappers¶

LV_USE_STDLIB_MALLOC / LV_USE_STDLIB_STRING / LV_USE_STDLIB_SPRINTF¶

Value: LV_STDLIB_BUILTIN. All three are set to use LVGL's own built-in implementations since no libc is available in the bare-metal environment.

Memory Pool¶

LV_MEM_SIZE¶

Value: 256 * 1024U (256 KB). Size of LVGL's internal memory pool for widget allocations and draw buffers.

LV_MEM_POOL_EXPAND_SIZE¶

Value: 0. Pool expansion is disabled; the 256 KB allocation is fixed.

LV_MEM_ADR¶

Value: 0. LVGL allocates the pool itself rather than using a fixed address.

HAL Settings¶

LV_DEF_REFR_PERIOD¶

Value: 33 (milliseconds). Targets approximately 30 frames per second.

LV_DPI_DEF¶

Value: 96. Standard screen DPI assumption.

Operating System¶

LV_USE_OS¶

Value: LV_OS_NONE. No OS abstraction layer; LVGL runs in a bare-metal cooperative model.

Rendering Configuration¶

LV_USE_DRAW_SW¶

Value: 1. The software renderer is the sole rendering backend.

Only the color formats actually used are enabled within the software renderer:

Define	Value	Description
`LV_DRAW_SW_SUPPORT_XRGB8888`	1	Primary framebuffer format
`LV_DRAW_SW_SUPPORT_ARGB8888`	1	Alpha-blended surfaces
`LV_DRAW_SW_SUPPORT_RGB888`	1	24-bit fallback
`LV_DRAW_SW_SUPPORT_RGB565`	0	Disabled
All other formats	0	Disabled

LV_DRAW_SW_COMPLEX¶

Value: 1. Enables complex draw operations (shadows, rounded corners). Shadow cache is disabled (LV_DRAW_SW_SHADOW_CACHE_SIZE = 0); circle cache is set to 4 entries.

LV_DRAW_LAYER_SIMPLE_BUF_SIZE¶

Value: 24 * 1024 (24 KB). Buffer for simple layer rendering.

GPU Backends¶

All GPU-accelerated backends are disabled: VGLite, PXP, Dave2D, SDL, VG-Lite.

Logging¶

LV_USE_LOG¶

Value: 1. Logging is enabled at LV_LOG_LEVEL_WARN. Printf-based logging, timestamps, and file/line info are all disabled to reduce overhead. All trace categories (memory, timer, indev, display refresh, events, object creation, layout, animation, cache) are disabled.

Assertions¶

LV_USE_ASSERT_NULL / LV_USE_ASSERT_MALLOC¶

Value: 1. Null-pointer and malloc-failure assertions are active.

LV_ASSERT_HANDLER¶

Value: {} (no-op). The assert handler intentionally does nothing to avoid hanging the kernel on a failed assertion.

Fonts¶

LV_FONT_MONTSERRAT_14¶

Value: 1. The only built-in Montserrat size enabled.

LV_FONT_DEFAULT¶

Value: &lv_font_montserrat_14. All other Montserrat sizes (8--48), compressed variants, and alternative font families (DejaVu, SimSun, UNSCII) are disabled.

Text Settings¶

LV_TXT_ENC¶

Value: LV_TXT_ENC_UTF8. UTF-8 text encoding. BiDi and Arabic/Persian character support are disabled.

Widgets¶

Enabled widgets: AnimImg, Arc, Bar, Button, ButtonMatrix, Checkbox, Dropdown, Image, Keyboard, Label, Line, List, MsgBox, Roller, Slider, Spinner, Switch, TextArea, Table, TabView, Win.

Disabled widgets: Calendar, Canvas, Chart, ImageButton, LED, Lottie, Menu, Scale, Span, SpinBox, TileView.

Themes¶

LV_USE_THEME_DEFAULT¶

Value: 1. Dark mode enabled (LV_THEME_DEFAULT_DARK = 1) with 80 ms transition time.

LV_USE_THEME_SIMPLE¶

Value: 1.

LV_USE_THEME_MONO¶

Value: 0.

Layouts¶

Both Flex and Grid layout engines are enabled.

Third-Party Libraries¶

All filesystem drivers are disabled (stdio, POSIX, Win32, FatFS, MemFS, LittleFS). All image decoders are disabled (PNG, BMP, JPEG, GIF, RLE). FreeType, TinyTTF, Rlottie, vector graphics, LZ4, and FFmpeg are all disabled.

Device Drivers¶

All platform-specific device drivers are disabled (SDL, X11, Wayland, Linux FBDEV, Linux DRM, NuttX, various SPI display controllers, Windows, OpenGLES, QNX). Display and input are handled by Asuro's own HAL layer.

Examples and Demos¶

All built-in examples and demo applications are disabled.

Notes¶

The configuration is designed for minimal footprint. Features are enabled only when required by the Asuro desktop shell.
Since no libc is linked, all string, memory, and formatting operations fall through to LVGL's internal implementations.
The assert handler is a deliberate no-op to prevent the kernel from halting on non-critical UI assertion failures.
The 256 KB memory pool is fixed and cannot expand at runtime. UI complexity must stay within this budget.