GDSetScale sets a screen graphics device to a new scale.
pascal OSErr GDSetScale(GDHandle gdh,Fixed scale,short flags)
gdh A handle to a screen graphics device.
scale A fixed point scale value.
flags Always pass 0.
Errors:
cDevErr Not a screen device.
controlErr Video driver can not respond to this call.
See also: QuickTime Tech Note QT4.