message: Add transform method to DrawParam
diff: @@ -204,6 +204,15 @@ impl DrawParam {
  }
  }
  + /// Set the transformation matrix of the drawable.
  + pub fn transform<M>(mut self, transform: M) -> Self
  + where
  + M: Into<mint::ColumnMatrix4<f32>>,
  + {
  + self.trans = Transform::Matrix(transform.into());
  + self
  + }
  +
  pub(crate) fn to_instance_properties(&self, srgb: bool) -> InstanceProperties {
  let mat: [[f32; 4]; 4] = *self.trans.to_bare_matrix().as_ref();
  let color: [f32; 4] = if srgb {
  