How Turtle can save the whole canvas to .eps file if the screen size is bigger than my monitor screen size

for example, my monitor screen size is 1900x800, but my canvas has to be 2000x1500 size to contain all my picture, but if i use below code to save my picture, only the picture in the screen (about 1900x800) saved, it’s only part of my picture.

i can’t make sure the picture is smaller then the screen, cause this program will automatically draw picture per the objects.

so question is:how could i save the whole picture? very appreciate for any help!

ts = tu.getscreen()