Bitmap Images Versus Vector Graphics

Bitmap images improve performance, because they are rendered already. The caveat is that they will often result in larger file sizes. For complex backgrounds, there’s no way around using bitmap images, because animation on top of a complex vector background would be very slow. However, on a small device screen, a lot of that detail will be lost anyway.

Vector backgrounds, on the other hand, can scale without loss in quality. This can be very beneficial to your file size, or when creating Flash Lite content for more than one screen size. For bitmaps to look their best, they need to be displayed at 100%, no scaling applied.

For our “2001” animation, we optimized the original vector backgrounds (see Figure 4).

Figure 4: A simple vector background helps animation performance.

They were simple enough, and are used at different sizes. However, on the splash screen, we’re using a 2K PNG file (see Figure 5). There was just no way to create the polka dots small enough in Flash. And with the PNG file there’s no quality loss—a JPEG would have either been the size of the vector art, or shown too many artifacts to be useful.

Figure 5: Bitmaps help performance and can be smaller in size.

Bitmap images versus vector graphics is not an either-or question—each has its place, so choose wisely.