lvgl/lvgl v5.2-rc on GitHub

New objects

Line draw algorithm is improved to support perpendicular line endings
Arc drawing
Shadow drawing improvements
Custom VDB write function can be registered in the display driver to support non-standard color formats. This the VDB content can be directly flushed to the display.
RGB565 swap to swap the two bytes of RGB565 colors. It makes possible to simply send the pixel's data via a 8-bit serial interface (e.g. SPI). It can be enabled in lv_conf.h by setting LV_COLOR_16_SWAP.
VDB address can be set in runtime with lv_vdb_set_adr(). Useful if you want to use DMA in the disp_flush function but the VDB need to be allocated in a specific way.
New image formats supporting Indexed and Grayscale formats too to save memory
Image decoder interface to add support to any image format like PNG
Dithering support in Online image converter

lv_obj opa scale attribute added to scale the current opacity of an object and its children (useful to fade in/out a group of objects)
lv_label LV_LABEL_ALIGN_RIGHT added to enable right alignmenet of texts.
lv_label LV_LABEL_LONG_CROP long mode to simply crop the text out of the label's size.
lv_btn Ink effect feature added to play an animation effect when a button is clicked and released. Can be enabled with lv_btn_set_ink_in_time(), lv_btn_set_ink_wait_time(), lv_btn_set_ink_out_time() and LV_BTN_INK_EFFECT` need to be enabled in lv_conf.h.
lv_page, lv_win, lv_ta scrolling is added on LV_GROUP_KEY_UP/DOWN/LEFT/RIGHT
lv_page temporal scrollbar hide option is added (LV_SB_MODE_HIDE)
lv_ta max_length and accepted_chars attributes are added.d to be enabled in lv_conf.h.
lv_ta action can be added with lv_ta_set_action()

SYMBOL_DUMMY: If added before string then lv_img will display the text. This way where icons need and an image a text can be set as well.
Monospace font support (set the width in the Online converter)
LV_FONT_CUSTOM define added in lv_conf.h where you can enumerate you custom fonts to make them global
LV_CONF_INCLUDE_SIMPLE: define it as a compiler symbol to include lv_conf.h like include "lv_conf.h" instead of using its relative path.
Click focus: you can enable focusing on an object in a group when it is clicked by a pointer an input device (mouse or touchpad)
Add LV_GROUP_KEY_DEL
Log system added to print useful debug info
Uniscii monospace font is added as built-in font
Edit/Navigate mode can be enabled for objects in a group. Useful for encoder based navigation.
Adding a new character encoding interface (other than the built-in UTF-8) made easy
LV_INDEV_TYPE_ENCODER: Encoder input device type (Left/Right/Push)
Opportunity to use your existing tick handler instead of lv_tick_inc. See lv_conf_templ.h
Themes can be changed in runtime (set LV_THEME_LIVE_UPDATE in lv_conf.h)
A new theme called: Nemo
lv_fs_trunc and lv_fs_rename added