BackgroundBitmap
视图操作指令。
Manage a background image in a viewport.
Create a plane that hides objects.
Open the Display panel.
Set the scale and center of all viewports to match the active viewport.
Save an image of the current view to the Windows Clipboard.
Save an image of the current view to a file.
Title, size, projection, camera and target, lens length, wallpaper.
