/lvgl

Powerful and easy-to-use embedded GUI with many widgets, advanced visual effects (opacity, antialiasing, animations) and low memory requirements (16K RAM, 64K Flash).

Primary LanguageCMIT LicenseMIT

LVGL - Light and Versatile Graphics Library

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


Features

  • Powerful building blocks: buttons, charts, lists, sliders, images, etc.
  • Advanced graphics: animations, anti-aliasing, opacity, smooth scrolling
  • Simultaneously use various input devices: touchscreen, mouse, keyboard, encoder, buttons, etc.
  • Simultaneously use multiple displays: e.g. monochrome and color display
  • Multi-language support with UTF-8 encoding, Bidirectional support, and Arabic text handling
  • Fully customizable graphical elements via CSS-like styles
  • Hardware independent to use with any microcontroller or display
  • Scalable to operate with little memory (64 kB Flash, 10 kB RAM)
  • OS, External memory and GPU are supported but not required
  • Single frame buffer operation even with advances graphical effects
  • Written in C for maximal compatibility (C++ compatible)
  • Micropython Binding exposes LVGL API in Micropython
  • Simulator to develop on PC without embedded hardware
  • Tutorials, examples, themes for rapid development
  • Documentation and API references

Supported devices

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

  • 16, 32 or 64 bit microcontroller or processor
  • > 16 MHz clock speed is recommended
  • Flash/ROM: > 64 kB for the very essential components (> 180 kB is recommended)
  • RAM:
    • Static RAM usage: ~2 kB depending on the used features and objects types
    • Stack: > 2kB (> 8 kB is recommended)
    • Dynamic data (heap): > 2 KB (> 16 kB is recommended if using several objects). Set by LV_MEM_SIZE in lv_conf.h.
    • Display buffer: > "Horizontal resolution" pixels (> 10 × "Horizontal resolution" is recommended)
  • C99 or newer compiler

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

Just to mention some platforms:

Get started

his 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. Read the Quick overview page of the documentation (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 got 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 lv_examples repository.

Button with label

lv_obj_t * btn = lv_btn_create(lv_scr_act(), NULL);     /*Add a button 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_set_event_cb(btn, btn_event_cb);                 /*Assign a callback to the button*/

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

...

void btn_event_cb(lv_obj_t * btn, lv_event_t event)
{
    if(event == LV_EVENT_CLICKED) {
        printf("Clicked\n");
    }
}

LVGL button with label example

LVGL from Micropython

Learn more about Micropython.

# Create a Button and a Label
scr = lv.obj()
btn = lv.btn(scr)
btn.align(lv.scr_act(), lv.ALIGN.CENTER, 0, 0)
label = lv.label(btn)
label.set_text("Button")

# Load the screen
lv.scr_load(scr)

Contributing

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