doodle/ui/frame.go

package ui

import (
	"fmt"

	"git.kirsle.net/apps/doodle/render"
)

// Frame is a widget that contains other widgets.
type Frame struct {
	Name string
	BaseWidget
	packs   map[Anchor][]packedWidget
	widgets []Widget
}

// NewFrame creates a new Frame.
func NewFrame(name string) *Frame {
	w := &Frame{
		Name:    name,
		packs:   map[Anchor][]packedWidget{},
		widgets: []Widget{},
	}
	w.IDFunc(func() string {
		return fmt.Sprintf("Frame<%s; %d widgets>",
			name,
			len(w.widgets),
		)
	})
	return w
}

// Setup ensures all the Frame's data is initialized and not null.
func (w *Frame) Setup() {
	if w.packs == nil {
		w.packs = map[Anchor][]packedWidget{}
	}
	if w.widgets == nil {
		w.widgets = []Widget{}
	}
}

// Compute the size of the Frame.
func (w *Frame) Compute(e render.Engine) {
	w.computePacked(e)
}

// Present the Frame.
func (w *Frame) Present(e render.Engine) {
	var (
		P = w.Point()
		S = w.Size()
	)

	// Draw the widget's border and everything.
	w.DrawBox(e)

	// Draw the background color.
	e.DrawBox(w.Background(), render.Rect{
		X: P.X + w.BoxThickness(1),
		Y: P.Y + w.BoxThickness(1),
		W: S.W - w.BoxThickness(2),
		H: S.H - w.BoxThickness(2),
	})

	// Draw the widgets.
	for _, child := range w.widgets {
		p := child.Point()
		child.MoveTo(render.NewPoint(
			P.X+p.X+w.BoxThickness(1),
			P.Y+p.Y+w.BoxThickness(1),
		))
		child.Present(e)
	}
}