func (a *AnchorLayout) PreferredSize(widgets []PreferredSizeLocateableWidget) (int, int) {
	px, py := a.padding.Dx(), a.padding.Dy()
	if len(widgets) == 0 {
		return px, py
	}
	w, h := widgets[0].PreferredSize()
	return w + px, h + py
}
PreferredSize implements Layouter.
package widget
import "image"
type AnchorLayout struct {
	padding Insets
}
type AnchorLayoutOpt func(a *AnchorLayout)
type AnchorLayoutOptions struct {
}
type AnchorLayoutPosition int
type AnchorLayoutData struct {
	HorizontalPosition AnchorLayoutPosition
	VerticalPosition AnchorLayoutPosition
	StretchHorizontal bool
	StretchVertical bool
}
const (
	AnchorLayoutPositionStart = AnchorLayoutPosition(iota)
	AnchorLayoutPositionCenter
	AnchorLayoutPositionEnd
)
var AnchorLayoutOpts AnchorLayoutOptions
func NewAnchorLayout(opts ...AnchorLayoutOpt) *AnchorLayout {
	a := &AnchorLayout{}
	for _, o := range opts {
		o(a)
	}
	return a
}
func (o AnchorLayoutOptions) Padding(i Insets) AnchorLayoutOpt {
	return func(a *AnchorLayout) {
		a.padding = i
	}
}