paint method
Draw itself and its children, according to the calculated
box.offset
Implementation
@override
void paint(Context context) {
super.paint(context);
final rect = context.localToGlobal(box!);
_paintImage(
canvas: context.canvas,
image: image.resolve(context, rect.size, dpi: dpi),
rect: box!,
alignment: alignment,
fit: fit,
);
}