Scaling the output Windows Size for the Node-Webkit Modus

is there any chance, to scale the windows size for the node webkit output mode? for example: im programming a retro game in 300x200 pixel, but i want the output x2 or x4, in 600x200 or 1200x400 so the screen is bigger and the game looks more pixelated.

nobody has an idea? a fullscreen node-webkit output would also be helpful. anybody has an idea or hint?

is there any chance, to scale the windows size for the node webkit output mode? for example: im programming a retro game in 300x200 pixel, but i want the output x2 or x4, in 600x200 or 1200x400 so the screen is bigger and the game looks more pixelated.

Letterbox integer scale does exactly that, however it puts black bars on the sides