Start the image viewer.
The image viewer will be started, if found. Calling this function when the viewer has already been started will not cause a second viewer to be started. The image viewer will be started automatically by any of the commands like image_data.
Close the image viewer.
Delete all the frames open in the image viewer.
Return the region defined in the image viewer.
Set the region to display in the image viewer.
Return the result of an XPA call to the image viewer.
Send an XPA command to the image viewer.
Image visualization is optional, and provided by the DS9 application 1.