I would like to use SDL_ttf to draw lettering over a potentially complex image, such that the lettering is opaque but no background box is drawn; the background is transparent. Is this possible? Here’s my attempt; I had hoped that by making bgColor transparent I might achieve this result. But no, my lettering still appears surrounded by black boxes.

I’m trying to make a menu using the SDL2. I have several items consisting of a few indicative words, that I make into surfaces using TTF_RenderText_Blended, then make them into textures through SDL_CreateTextureFromSurface, then display them all in a column, one below another. This works fine, but for the sake of interactivity, I want to make the keyboard shortcut for each item explicit through underlining the corresponding character in each item.