LVGL Arduino examples

LVGL can be installed via Arduino IDE Library Manager or as an .ZIP library. It will install lv_exmaples which contains a lot of examples and demos to try LVGL.

Example

There are simple examples which use the TFT_eSPI library as a TFT driver to simplify testing. To get all this to work you have to setup TFT_eSPI to work with your TFT display type via editing the User_Setup.h file in TFT_eSPI library folder, or by selecting your own configurtion in the User_Setup_Select.h file in TFT_eSPI library folder.

LVGL library has its own configuration file called lv_conf.h. When LVGL is installed to followings needs to be done to configure it:

Go to directory of the installed Arduno libraries
Go to lvgl and copy lv_conf_template.h as lv_conf.h next to the src folder.
Open lv_conf.h and change the first #if 0 to #if 1
Set the resolution of your display in LV_HOR_RES_MAX and LV_VER_RES_MAX
Set the color depth of you display in LV_COLOR_DEPTH
Set LV_TICK_CUSTOM 1

Debugging

In case of trouble there are debug informations inside LVGL. In the ESP32_TFT_eSPI example there is my_print method, which allow to send this debug informations to the serial interface. To enable this feature you have to edit lv_conf.h file and enable logging in section log settings:

/*Log settings*/
#define USE_LV_LOG      1   /*Enable/disable the log module*/
#if LV_USE_LOG
/* How important log should be added:
 * LV_LOG_LEVEL_TRACE       A lot of logs to give detailed information
 * LV_LOG_LEVEL_INFO        Log important events
 * LV_LOG_LEVEL_WARN        Log if something unwanted happened but didn't cause a problem
 * LV_LOG_LEVEL_ERROR       Only critical issue, when the system may fail
 * LV_LOG_LEVEL_NONE        Do not log anything
 */
#  define LV_LOG_LEVEL    LV_LOG_LEVEL_WARN

After enabling log module and setting LV_LOG_LEVEL accordingly the output log is sent to the Serial port @ 115200 Bd.