renderer: describe at parameter in Frame::clear
@@ -122,6 +122,9 @@ pub trait Frame {
/// Clear the complete current target with a single given color.
///
+ /// The `at` parameter specifies a set of rectangles to clear in the current target. This allows partially
+ /// clearing the target which may be useful for damaged rendering.
+ ///
/// This operation is only valid in between a `begin` and `finish`-call.
/// If called outside this operation may error-out, do nothing or modify future rendering results in any way.
fn clear(&mut self, color: [f32; 4], at: &[Rectangle<i32, Physical>]) -> Result<(), Self::Error>;
