lvgl/docs

LittleV Graphics Libraray

LittlevGL is a graphics library to create Graphical User Interfaces (GUI) on TFT, LCD or monochrome displays using microcontroller based embedded systems.

Transparency, anti-aliassing and smooth animations can be used with no double buffering so typically no external memories are required.

The graphics library is written in C and it is completely hardware independent. You can even run it in a PC simulator without any embedded hardware.

Homepage: http://gl.littlev.hu

Key features

• Hardware independent, support any modern microcontroller
• High resolution TFTs, monochrome or any type of display supported (24/16/8/1 bit color depth)
• External RAM, FPU or GPU not required just optional
• Build GUI from simple graphical objects
  • Buttons, Labels, Images
  • Charts, Lists, Bars, Sliders, Text areas etc.
• High level graphical features without double buffering
  • Antialiassing (font or full screen)
  • Animations
  • Transparency
  • Gradient colors
  • Smooth dragging and scrolling
  • Layers
• Customizable appearance with styles
• Applications for complex tasks
• Can run in a PC simulator
• Modular and well-structured source code
• Actively developed

Porting

The following functions has to be provided

• hal/disp disp_fill(x1, y1, x2, y2, color) to fill area with a color
• hal/disp disp_map(x1, y1, x2, y2, &color_array) copy a color map to an area
• hal/disp disp_color_cpy(dest, src, length, opa) copy pixel, optional for GPU
• hal/indev indev_get(id, &x, &y) get the x and y coordinates from an input device (e.g. touch pad)
• hal/systick systick_get() get a system tick with 1 ms resolution
• hal/systick systick_elapse(prev_time) get the elapsed milliseconds sience prev_time

See the example HAL repository!

Requirements

• Misc. library is used by the graphics library

Project set-up

1. Clone or download the following repositories:
   • lvgl:git clone https://github.com/littlevgl/lvgl.git
   • misc: git clone https://github.com/littlevgl/misc.git
   • hal: git clone https://github.com/littlevgl/hal.git
2. Create project with your prefered IDE and add the lvgl, misc and hal folders
3. Add your projects root directory as include path
4. Write your display, touch pad and system tick drivers in hal
5. Copy lvgl/lv_conf_templ.h as lv_conf.h and misc/misc_conf_templ.h as misc_conf.h to the projects root folder
6. In the *_conf.h files delete the first #if 0 and its #endif. Let the default configurations at first.
7. In your main.c include:
   • #include "misc/misc.h"
   • #include "misc/os/ptask.h"
   • #include "lvgl/lvgl.h"
8. In your main.c intialize:
   • misc_init();
   • your_systick_init();
   • your_disp_init();
   • your_indev_init();
   • lvgl_init();
9. To test create a label: lv_obj_t * label = lv_label_create(lv_scr_act(), NULL);
10. In the main while(1) call ptask_handler(); and make a few milliseconds delay (e.g. your_delay_ms(5);)
11. Compile the code and load it to your embedded hardware

PC Simulator

If you don't have got an embedded hardware you can test the graphics library in a PC simulator. The simulator uses SDL2 to emulate a display on your monitor and a touch pad with your mouse.

There is a pre-configured PC project for Eclipse CDT in this repository: https://github.com/littlevgl/proj_pc

Contributing

See CONTRIBUTING.md

Donate

If you are pleased with the graphics library and found it useful please support its further development: