I finished an mpr display, but I found a problem where I used the vtkCornerAnnotation class to synchronize the window width display in each window when adjusting the window width. However, I found that the rendering speed when updating the value of vtkCornerAnnotation was slow, which caused the window to freeze, and I was pretty sure that it was due to the stuttering generated by this class, and once I blocked the code changed by vtkCornerAnnotation, the window tuning became very flowing.