turtle.setup()

turtle.setup(width=0.5, height=0.75, startx=None, starty=None)

Set the size and position of the main window.

Arguments: width: as integer a size in pixels, as float a fraction of the

Default is 50% of
height: as integer the height in pixels, as float a fraction of the
Default is 75% of
startx: if positive, starting position in pixels from the left
edge of the screen, if negative from the right edge Default, startx=None is to center window horizontally.
starty: if positive, starting position in pixels from the top
edge of the screen, if negative from the bottom edge Default, starty=None is to center window vertically.

Examples: >>> setup (width=200, height=200, startx=0, starty=0)

sets window to 200x200 pixels, in upper left of screen

>>> setup(width=.75, height=0.5, startx=None, starty=None)

sets window to 75% of screen by 50% of screen and centers