...
FS = -1

do
	If GetRawKeyPressed(112) // [F1] Key
		FS = -FS
		If FS = 1 then SetWindowSize( 1024, 768, 1 ) else SetWindowSize( 1024, 768, 0 )
		UpdateDeviceSize(1024,768)
	EndIf
...
loop

SetErrorMode(2)

#CONSTANT Platform$ = GetDeviceBaseName()

// set window properties
SetWindowTitle( "Studio Fullscreen" )

SetWindowSize( 1024, 768, 0 )

SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 )

FS = -1
RED = MakeColor(255,0,0)

do
	If GetRawKeyPressed(112) // [F1] Key
		FS = -FS
		If FS = 1 then SetWindowSize( 1024, 768, 1 ) else SetWindowSize( 1024, 768, 0 )
		UpdateDeviceSize(1024,768)
	EndIf
	DrawBox(0,0,1023,767,Red, Red, Red, Red, 0)
    Print( "[F1] Toggle Fullscreen" )
    Print( "Window: " + STR(GetWindowWidth()) + "x" + STR(GetWindowHeight()))
    Print( "Base: " + STR(GetDeviceWidth()) + "x" + STR(GetDeviceHeight()) )
    Print( "Max: " + STR(GetMaxDeviceWidth()) + "x" + STR(GetMaxDeviceHeight()) )
    Sync()
loop