- l
- the left position of the dirty region
- t
- the top position of the dirty region
- r
- the right position of the dirty region
- b
- the bottom position of the dirty region
Mark the area defined by the rect (l,t,r,b) as needing to be drawn. The coordinates of the dirty rect are relative to the view. If the view is visible, View.OnDraw(Android.Graphics.Canvas) will be called at some point in the future.
This must be called from a UI thread. To call from a non-UI thread, call View.PostInvalidate.