I want to draw everything according to a fixed frame, say 1600x900, and then stretch or shrink the complete image according to actual window size. For example if the window is 1920x1080 then everything is slightly stretched but if it's 1024×768 then the image is shrunk down.
The SFML window seems to do this automatically if I create a window, draw something and manually resize the window, but how do I achieve the same effect by default?