How to set a rgba color palette?

[Asukaaaaaa]

encoder.set_palette seems only accept a Vec<u8>, how to describe a rgba color in u8 type?
If i pass a 1024 size Vec<u8> palette, just get a broken image😮.

[anforowicz]

I think you have to set the RGB part (corresponding to a PLTE chunk in a PNG file) using Encoder.set_palette and then set the Alpha part (corresponding to a tRNS chunk in a PNG file) using Encoder::set_trns