How to resize my 2d game to fit the screen?

Question

I am currently making a 2D game using Java (Java 2D). I want to make my game resizable. If you play any game on an emulator (e.g. legend of Zelda in fceux emulator) in full screen mode, you'll see that the 8-bit or 16-bit game re-sizes to fit the screen size. How can I implement the same thing in my game programatically?

Answer 1

I'm assuming you're using the standard Java 2D API, not OpenGL.

In that case, you render your graphics to a buffer image first. Then, to render that image to the screen, you can either use a Graphics.drawImage call that allows resizing your buffered image:

public abstract boolean drawImage(Image img,        // the buffer image
                int dx1, int dy1, int dx2, int dy2, // 0, 0, screen.w, screen.h
                int sx1, int sy1, int sx2, int sy2, // 0, 0, image.w, image.h
                ImageObserver observer)             // null is fine

or, if you want to have more control over the scaling algorithm, you can first convert the image to a second buffered image using the following method of the Image class:

public Image getScaledInstance(int width, int height, int hints)

Here, the parameter hints is one of

Image.SCALE_DEFAULT
Image.SCALE_FAST
Image.SCALE_SMOOTH
Image.SCALE_REPLICATE
Image.SCALE_AREA_AVERAGING

See the API doc for details. For bigger games, you might want to keep an eye on performance doing these rescales, but for typical 8-bit resolutions you should probably be fine.