internal ManualRenderer(IntPtr platformHandle,
                         PreDisposeHandlerDelegate preDisposeDelegate)
 {
     _platformHandle     = platformHandle;
     _preDisposeDelegate = preDisposeDelegate;
     _rendererId         = -1;
     _invalidateCallback = new invalidate_clbck_t(invalidateClbck);
 }
 internal ManualRenderer(IntPtr platformHandle,
     PreDisposeHandlerDelegate preDisposeDelegate)
 {
     _platformHandle = platformHandle;
     _preDisposeDelegate = preDisposeDelegate;
     _rendererId = -1;
     _invalidateCallback = new invalidate_clbck_t(invalidateClbck);
 }