LVGL v8.2 on ESP32-S3 colour issue ILI9341 TFT LCD Arduino IDE

Question

I have ILI9341 320x240px TFT LCD screen which I am using with ESP32-S3-wroom-1 module.

I have tested with TFT_eSPI and works fine, but when using LVGL, I am seeing weird artefacts on the edges. enter image description here

I am using Arduino IDE

Started off the sketch from

https://github.com/lvgl/lvgl/blob/master/examples/arduino/LVGL_Arduino/LVGL_Arduino.ino

Havent changed sketch file much.

I am using LVGL latest v8.2.0

/*====================
 COLOR SETTINGS
 *====================*/
/*Color depth: 1 (1 byte per pixel), 8 (RGB332), 16 (RGB565), 32 (ARGB8888)*/
#define LV_COLOR_DEPTH 16
/*Swap the 2 bytes of RGB565 color. Useful if the display has an 8-bit interface (e.g. SPI)*/
#define LV_COLOR_16_SWAP 1
/*Enable features to draw on transparent background.
 *It's required if opa, and transform_* style properties are used.
 *Can be also used if the UI is above another layer, e.g. an OSD menu or video player.*/
#define LV_COLOR_SCREEN_TRANSP 1
/* Adjust color mix functions rounding. GPUs might calculate color mix (blending) differently.
 * 0: round down, 64: round up from x.75, 128: round up from half, 192: round up from x.25, 254: round up */
#define LV_COLOR_MIX_ROUND_OFS 0
/*Images pixels with this color will not be drawn if they are chroma keyed)*/
#define LV_COLOR_CHROMA_KEY lv_color_hex(0x00ff00) /*pure green*/

LV_COLOR_SCREEN_TRANSP 1 was originally 0 changing it did not change anything.

I am following the FAQ which mentions

1.6.7 Why I see nonsense colors on the screen? Probably LVGL's color format is not compatible with your displays color format. Check LV_COLOR_DEPTH in lv_conf.h. If you are using 16 bit colors with SPI (or other byte-oriented interface) probably you need to set LV_COLOR_16_SWAP 1 in lv_conf.h. It swaps the upper and lower bytes of the pixels.

as you can see above in the config, the values are as recommended.

Any help will be greatly appreciated.

Answer 1

Turns out, I had to disable LV_COLOR_16_SWAP I had been trying with different colour depths and everything else, I still cannot see gradients drawn properly, but the colours seem to be correct now.enter image description here

• Steve Meisner: I am encountering the exact same problem, using the same ESP32-S3, but using ESP-IDF framework; not Arduino. My solution was exactly the same as yours; comment out the LV_COLOR_16_SWAP in the generated ui.c. BTW, the project I am working on is here: github.com/smeisner/smart-thermostat I am hoping this gets fixed sometime soon!
• Steve Meisner: BTW, I found this on the SquareLine Studio forum: forum.squareline.io/t/…
• Anil Maharjan: Thanks @SteveMeisner for sharing the link