My application uses "transparent" bitmaps. The background of some themes may make these bitmaps hard to see.

Is there a way to change the bitmap I use according to the theme?

How is a theme identified? Is it only by name, id, or something of the sort, or does it have some properties, stating the type of the theme (for example - I'm a dark theme, mostly using shades of blue)? I ask this, because in the first case applications can only prepare themselves for several well-known themes, but not for custom ones.