Littlev Graphics Library

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.
https://littlevgl.com

Key features

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 (50 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
Simulator to develop on PC without embedded hardware
Tutorials, examples, themes for rapid development
Documentation and API references online

Porting

In the simplest case you need 5 things:

Call lv_tick_inc(x) every x milliseconds in a Timer or Task (x should be between 1 and 10)
Register a function which can copy a pixel array to an area of the screen.
Register a function which can read an input device. (E.g. touch pad)
Copy lv_conf_templ.h as lv_conf.h and set at least LV_HOR_RES, LV_VER_RES and LV_COLOR_DEPTH.
Call lv_task_handler() periodically every few milliseconds. For a detailed description visit https://github.com/littlevgl/lvgl/wiki/Porting Or check the Porting tutorial

Project set-up

Clone or Download the lvgl repository: git clone https://github.com/littlevgl/lvgl.git
Create project with your preferred IDE and add the lvgl folder
Copy lvgl/lv_conf_templ.h as lv_conf.h next to the lvgl folder
In the lv_conf.h delete the first #if 0 and its #endif. Leave the default configuration for the first try.
In your main.c: #include "lvgl/lvgl.h"
In your main function:
- lvgl_init();
- tick, display and input device initialization (see above)
To test create a label: lv_obj_t * label = lv_label_create(lv_scr_act(), NULL);
In the main while(1) call lv_task_handler(); and make a few milliseconds delay (e.g. my_delay_ms(5);)
Compile the code and load it to your embedded hardware

PC Simulator

You can test the graphics library in a PC simulator, if you don't have an embedded hardware. The simulator uses SDL2 library 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/pc_simulator