LittlevGL provides everything you need to create a Graphical User Interface (GUI) on embedded systems with easy-to-use graphical elements, beautiful visual effects and low memory footprint.
- Powerful building blocks buttons, charts, lists, sliders, images, etc.
- Advanced graphics with animations, anti-aliasing, opacity, smooth scrolling
- Various input devices touch pad, mouse, keyboard, encoder, buttons, etc.
- Multi-language support with UTF-8 encoding
- Fully customizable graphical elements
- 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 supported but not required
- Single frame buffer operation even with advances graphical effects
- Written in C for maximal compatibility
- Micropython Binding exposes LittlevGL API in Micropython
- Simulator to develop on PC without embedded hardware
- Tutorials, examples, themes for rapid development
- Documentation and API references online
Basically, every modern controller - which is able to drive a display - is suitable to run LittlevGL. The minimal requirements:
- 16, 32 or 64-bit microcontroller or processor
- > 16 MHz clock speed
- > 8 kB RAM for static data and > 2 KB RAM for dynamic data (graphical objects)
- > 64 kB flash program memory
- Optionally ~1/10 screen sized memory for buffered drawing (on 240 × 320, 16-bit colors it's 15 kB)
Just to mention some platforms:
- STM32F1, STM32F3, STM32F4, STM32F7
- Microchip dsPIC33, PIC24, PIC32MX, PIC32MZ
- NXP Kinetis, LPC, iMX
- Linux frame buffer (/dev/fb)
- Raspberry PI
- Espressif ESP32
- Nordic nrf52
- Quectell M66
The easiest way to get started with LittlevGL is to run it in a simulator on your PC without any embedded hardware.
Choose a project with your favourite IDE:
| Eclipse | CodeBlocks | Visual Studio | PlatformIO | Qt Creator |
|---|---|---|---|---|
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| Cross-platform with SDL |
Native Windows | Cross-platform with SDL |
Cross-platform with SDL |
Cross-platform with SDL |
In the most simple case you need to do these steps:
- Copy
lv_conf_templ.haslv_conf.hnext tolvgland set at leastLV_HOR_RES,LV_VER_RESandLV_COLOR_DEPTH. - Call
lv_tick_inc(x)everyxmilliseconds in a Timer or Task (xshould be between 1 and 10). It is required for the internal timing of LittlevGL. - Call
lv_init() - Register a function which can copy a pixel array to an area of the screen:
lv_disp_drv_t disp_drv; /*Descriptor of a display driver*/
lv_disp_drv_init(&disp_drv); /*Basic initialization*/
disp_drv.disp_flush = disp_flush; /*Set your driver function*/
lv_disp_drv_register(&disp_drv); /*Finally register the driver*/
void disp_flush(int32_t x1, int32_t y1, int32_t x2, int32_t y2, const lv_color_t * color_p)
{
int32_t x, y;
for(y = y1; y <= y2; y++) {
for(x = x1; x <= x2; x++) {
sep_pixel(x, y, *color_p); /* Put a pixel to the display.*/
color_p++;
}
}
lv_flush_ready(); /* Tell you are ready with the flushing*/
}
- Register a function which can read an input device. E.g. for a touch pad:
lv_indev_drv_init(&indev_drv); /*Descriptor of a input device driver*/
indev_drv.type = LV_INDEV_TYPE_POINTER; /*Touch pad is a pointer-like device*/
indev_drv.read = touchpad_read; /*Set your driver function*/
lv_indev_drv_register(&indev_drv); /*Finally register the driver*/
bool touchpad_read(lv_indev_data_t * data)
{
static lv_coord_t last_x = 0;
static lv_coord_t last_y = 0;
/*Save the state and save the pressed coordinate*/
data->state = touchpad_is_pressed() ? LV_INDEV_STATE_PR : LV_INDEV_STATE_REL;
if(data->state == LV_INDEV_STATE_PR) touchpad_get_xy(&last_x, &last_y);
/*Set the coordinates (if released use the last pressed coordinates)*/
data->point.x = last_x;
data->point.y = last_y;
return false; /*Return `false` because we are not buffering and no more data to read*/
}- Call
lv_task_handler()periodically every few milliseconds in the mainwhile(1)loop, in Timer interrupt or in an Operation system task. It will redraw the screen if required, handle input devices etc.
For a detailed description check the Documentation or the Porting tutorial
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_btn_set_action(btn, LV_BTN_ACTION_CLICK, btn_action);/*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*/
lv_res_t btn_action(lv_obj_t * btn)
{
printf("Clicked\n");
return LV_RES_OK;
}
static lv_style_t style_btn_rel; /*A variable to store the released style*/
lv_style_copy(&style_btn_rel, &lv_style_plain); /*Initialize from a built-in style*/
style_btn_rel.body.border.color = LV_COLOR_HEX3(0x269);
style_btn_rel.body.border.width = 1;
style_btn_rel.body.main_color = LV_COLOR_HEX3(0xADF);
style_btn_rel.body.grad_color = LV_COLOR_HEX3(0x46B);
style_btn_rel.body.shadow.width = 4;
style_btn_rel.body.shadow.type = LV_SHADOW_BOTTOM;
style_btn_rel.body.radius = LV_RADIUS_CIRCLE;
style_btn_rel.text.color = LV_COLOR_HEX3(0xDEF);
static lv_style_t style_btn_pr; /*A variable to store the pressed style*/
lv_style_copy(&style_btn_pr, &style_btn_rel); /*Initialize from the released style*/
style_btn_pr.body.border.color = LV_COLOR_HEX3(0x46B);
style_btn_pr.body.main_color = LV_COLOR_HEX3(0x8BD);
style_btn_pr.body.grad_color = LV_COLOR_HEX3(0x24A);
style_btn_pr.body.shadow.width = 2;
style_btn_pr.text.color = LV_COLOR_HEX3(0xBCD);
lv_btn_set_style(btn, LV_BTN_STYLE_REL, &style_btn_rel); /*Set the button's released style*/
lv_btn_set_style(btn, LV_BTN_STYLE_PR, &style_btn_pr); /*Set the button's pressed style*/
/*Add some effects when the button is clicked*/
lv_btn_set_ink_in_time(btn, 300);
lv_btn_set_ink_wait_time(btn, 100);
lv_btn_set_ink_out_time(btn, 300);
# 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)Check out the Documentation for more!
To ask questions please use the Forum. FOr development related things (bug reports, feature suggestions) use GitHub's Issue tracker. You can contribute in several ways:
- Answer other's question in the Forum
- Report and/or fix bugs using the issue tracker and in Pull-request
- Suggest and/or implement new features using the issue tracker and in Pull-request
- Improve and/or translate the documentation learn more here
- Write a blog post about your experiences learn more here
- Upload your project or product as a reference to this site
Before contributing, please read CONTRIBUTING.md.
If you are pleased with the library, found it useful, or you are happy with the support you got, please help its further development:
