Performing library maintenance on my app - upgraded from 8.0.2 to 8.1.0, with no issues. Upgraded to 8.2.0, and images with colors that match LV_COLOR_CHROMA_KEY now render that color to the display (pure green) instead of appearing transparent. Downloaded code from master branch, still an issue.
(Update) - The images at issue are LV_IMG_CF_INDEXED_8BIT, which previously respected the transparent color. LV_IMG_CF_TRUE_COLOR_CHROMA_KEYED are fine.
I can see that the rendering engine had significant architectural upgrades in 8.2.0, but do not see any reference to 8.2.0 breaking the rendering of transparent images. Latest documentation for images still states:
Can have 256 different colors in a palette (always chroma keyed)