question about window size scaling

Is it possible to limit the size of the extended window to the specified size?

for example my game has original window width and height 840 x 480 but my desktop has full HD now when i click full screen i want maximum size of game window to 1280x 720 only

system -> set full screen scaling.....

piuuu there you can set only quality of scaling i need set a max size of window and lock to HD size if player try set to full screen