Tasmota/lib/libesp32_lvgl/lvgl

LVGL - Light and Versatile Graphics Library

LVGL provides everything you need to create an embedded GUI with easy-to-use graphical elements, beautiful visual effects and a low memory footprint.

Website · Docs · Forum · Services · Interactive examples

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Table of content

• Overview
• Get started
• Examples
• Services
• Contributing

Overview

Features

• Powerful building blocks: buttons, charts, lists, sliders, images, etc.
• Advanced graphics engine: animations, anti-aliasing, opacity, smooth scrolling, blending modes, etc
• Supports various input devices: touchscreen, mouse, keyboard, encoder, buttons, etc.
• Supports multiple displays
• Hardware independent, can be use with any microcontroller and display
• Scalable to operate with little memory (64 kB Flash, 16 kB RAM)
• Multi-language support with UTF-8 handling, CJK, Bidirectional and Arabic script support
• Fully customizable graphical elements via CSS-like styles
• Powerful layouts inspired by CSS: Flexbox and Grid
• OS, External memory and GPU are supported but not required. (built in support for STM32 DMA2D, SWM341 DMA2D, and NXP PXP and VGLite)
• Smooth rendering even with a single frame buffer
• Written in C and compatible with C++
• Micropython Binding exposes LVGL API in Micropython
• Simulator to develop on PC without embedded hardware
• 100+ simple Examples
• Documentation and API references online and in PDF

Requirements

Basically, every modern controller (which is able to drive a display) is suitable to run LVGL. The minimal requirements are:

Name	Minimal	Recommended
Architecture	16, 32 or 64 bit microcontroller or processor
Clock	> 16 MHz	> 48 MHz
Flash/ROM	> 64 kB	> 180 kB
Static RAM	> 16 kB	> 48 kB
Draw buffer	> 1 × hor. res. pixels	> 1/10 screen size
Compiler	C99 or newer

Note that the memory usage might vary depending on the architecture, compiler and build options.

Supported platforms

LVGL is completely platform independent and can be used with any MCU that fulfills the requirements. Just to mention some platforms:

• NXP: Kinetis, LPC, iMX, iMX RT
• STM32F1, STM32F3, STM32F4, STM32F7, STM32L4, STM32L5, STM32H7
• Microchip dsPIC33, PIC24, PIC32MX, PIC32MZ
• Linux frame buffer (/dev/fb)
• Raspberry Pi
• Espressif ESP32
• Infineon Aurix
• Nordic NRF52 Bluetooth modules
• Quectel modems
• SYNWIT SWM341

LVGL is also available as:

• Arduino library
• PlatformIO package
• Zephyr library
• ESP32 component
• NXP MCUXpresso component
• NuttX library
• RT-Thread RTOS

Get started

This list shows the recommended way of learning the library:

1. Check the Online demos to see LVGL in action (3 minutes)
2. Read the Introduction page of the documentation (5 minutes)
3. Get familiar with the basics on the Quick overview page (15 minutes)
4. Set up a Simulator (10 minutes)
5. Try out some Examples
6. Port LVGL to a board. See the Porting guide or check the ready to use Projects
7. Read the Overview page to get a better understanding of the library (2-3 hours)
8. Check the documentation of the Widgets to see their features and usage
9. If you have questions go to the Forum
10. Read the Contributing guide to see how you can help to improve LVGL (15 minutes)

Examples

For more examples see the examples folder.

C

lv_obj_t * btn = lv_btn_create(lv_scr_act());                   /*Add a button to the current screen*/
lv_obj_set_pos(btn, 10, 10);                                    /*Set its position*/
lv_obj_set_size(btn, 100, 50);                                  /*Set its size*/
lv_obj_add_event_cb(btn, btn_event_cb, LV_EVENT_CLICKED, NULL); /*Assign a callback to the button*/

lv_obj_t * label = lv_label_create(btn);                        /*Add a label to the button*/
lv_label_set_text(label, "Button");                             /*Set the labels text*/
lv_obj_center(label);                                           /*Align the label to the center*/
...

void btn_event_cb(lv_event_t * e)
{
  printf("Clicked\n");
}

Micropython

Learn more about Micropython.

def btn_event_cb(e):
  print("Clicked")

# Create a Button and a Label
btn = lv.btn(lv.scr_act())
btn.set_pos(10, 10)
btn.set_size(100, 50)
btn.add_event_cb(btn_event_cb, lv.EVENT.CLICKED, None)

label = lv.label(btn)
label.set_text("Button")
label.center()

Services

LVGL Kft was established to provide a solid background for LVGL library. We offer several type of services to help you in UI development:

• Graphics design
• UI implementation
• Consulting/Support

For more information see https://lvgl.io/services Feel free to contact us if you have any questions.

Contributing

LVGL is an open project and contribution is very welcome. There are many ways to contribute from simply speaking about your project, through writing examples, improving the documentation, fixing bugs to hosting your own project under the LVGL organization.

For a detailed description of contribution opportunities visit the Contributing section of the documentation.