zntg/ui/state.go

package ui

import (
	"log"
	"time"

	"opslag.de/schobers/galleg/allegro5"
	"opslag.de/schobers/geom"
)

type State interface {
	Enter(Context) error
	Leave(Context) error
	Update(Context, time.Duration) (State, error)
	Handle(Context, allegro5.Event) error
	Render(Context) error
}

type StateBase struct {
	Control  Control
	ChangeTo State
}

func (s *StateBase) Enter(ctx Context) error {
	if nil != s.Control {
		err := s.Control.Created(ctx, nil)
		if nil != err {
			log.Println("error creating control")
			s.Control = nil
		}
	}
	return nil
}

func (s *StateBase) Leave(ctx Context) error {
	if nil != s.Control {
		s.Control.Destroyed(ctx)
	}
	return nil
}

func (s *StateBase) Update(ctx Context, dt time.Duration) (State, error) {
	if nil != s.Control {
		s.Control.Update(ctx, dt)
	}
	return s.ChangeTo, nil
}

func (s *StateBase) Handle(ctx Context, ev allegro5.Event) error {
	if nil != s.Control {
		s.Control.Handle(ctx, ev)
	}
	return nil
}

func Arrange(ctx Context, c Control, rect geom.RectangleF) {
	if cont, ok := c.(Container); ok {
		cont.Arrange(ctx, rect)
	} else {
		c.SetRect(rect)
	}
}

func (s *StateBase) Render(ctx Context) error {
	if nil != s.Control {
		var disp = ctx.Display()
		Arrange(ctx, s.Control, geom.RectF(0, 0, float64(disp.Width()), float64(disp.Height())))
		s.Control.Render(ctx)
	}
	return nil
}