What's happening here?

This example demonstrates UINineSlice elements for creating scalable UI components with preserved border regions. A vignette overlay is created using nine-slice scaling that covers the entire layer while maintaining border quality at any size.

// Create nine-slice element with 15% border
const image = new UINineSlice(
  layer,
  baseScene.loadedTextures["T_Vignette"],
  { sliceBorder: 0.15 }
);

// Configure appearance
image.transparency = true;
image.opacity = 0.75;
image.color = 0xffa500;

// Use cover constraints to fill the entire layer
UICoverConstraintBuilder.build(layer, image);