To be honest, I don't know if this is a lingo question or not.
I'm using sprite trails. I have it so that when the mouse is clicking (and dragging) a sprite, the trails appear. Otherwise, they are turned off.
My sprites have transparent backgrounds. However, when a sprite with trails currently inactive moves over top of a trail, the trail is erased based on the bounding box of the sprite and not the visible edges of the sprite. Is there any way to make it so that trails are overwritten by the opaque part of a sprite instead of the entire bounding box? I tried using other types of inks, but no dice.