Remove Canvas

example/blocks.go

@@ -44,9 +44,9 @@ func main() {
 		defer pprof.StopCPUProfile()
 	}
 
-	u := new(glfw.UI)
+	ui := new(glfw.UI)
 	game := blocks.NewGame()
-	if err := ebiten.Run(u, game, blocks.ScreenWidth, blocks.ScreenHeight, 2, "Blocks (Ebiten Demo)", 60); err != nil {
+	if err := ebiten.Run(ui, game, blocks.ScreenWidth, blocks.ScreenHeight, 2, "Blocks (Ebiten Demo)", 60); err != nil {
 		log.Fatal(err)
 	}
 }

glfw/canvas.go

@@ -32,7 +32,7 @@ type canvas struct {
 	funcsDone chan struct{}
 }
 
-func (c *canvas) Draw(d ebiten.GraphicsContextDrawer) (err error) {
+func (c *canvas) draw(d ebiten.GraphicsContextDrawer) (err error) {
 	c.use(func() {
 		c.context.PreUpdate()
 	})
@@ -46,7 +46,7 @@ func (c *canvas) Draw(d ebiten.GraphicsContextDrawer) (err error) {
 	return
 }
 
-func (c *canvas) IsClosed() bool {
+func (c *canvas) isClosed() bool {
 	return c.window.ShouldClose()
 }
 

glfw/ui.go

@@ -34,14 +34,14 @@ type UI struct {
 	canvas *canvas
 }
 
-func (u *UI) Start(width, height, scale int, title string) (ebiten.Canvas, error) {
+func (u *UI) Start(width, height, scale int, title string) error {
 	if !glfw.Init() {
-		return nil, errors.New("glfw.Init() fails")
+		return errors.New("glfw.Init() fails")
 	}
 	glfw.WindowHint(glfw.Resizable, glfw.False)
 	window, err := glfw.CreateWindow(width*scale, height*scale, title, nil, nil)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	c := &canvas{
@@ -61,11 +61,11 @@ func (u *UI) Start(width, height, scale int, title string) (ebiten.Canvas, error
 		c.context, err = opengl.Initialize(width, height, realScale)
 	})
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	u.canvas = c
-	return c, nil
+	return nil
 }
 
 func (u *UI) DoEvents() {
@@ -76,3 +76,11 @@ func (u *UI) DoEvents() {
 func (u *UI) Terminate() {
 	glfw.Terminate()
 }
+
+func (u *UI) Draw(drawer ebiten.GraphicsContextDrawer) error {
+	return u.canvas.draw(drawer)
+}
+
+func (u *UI) IsClosed() bool {
+	return u.canvas.isClosed()
+}

run.go

@@ -32,8 +32,7 @@ type Game interface {
 // calls ui.DoEvent(), game.Update() and game.Draw() at a regular interval, and finally
 // calls ui.Terminate().
 func Run(ui UI, game Game, width, height, scale int, title string, fps int) error {
-	canvas, err := ui.Start(width, height, scale, title)
+	if err := ui.Start(width, height, scale, title); err != nil {
-	if err != nil {
 		return err
 	}
 
@@ -45,18 +44,18 @@ func Run(ui UI, game Game, width, height, scale int, title string, fps int) erro
 	defer ui.Terminate()
 	for {
 		ui.DoEvents()
+		if ui.IsClosed() {
+			return nil
+		}
 		select {
 		default:
-			if err := canvas.Draw(game); err != nil {
+			if err := ui.Draw(game); err != nil {
 				return err
 			}
 		case <-tick:
 			if err := game.Update(); err != nil {
 				return err
 			}
-			if canvas.IsClosed() {
-				return nil
-			}
 		case <-sigterm:
 			return nil
 		}

ui.go

@@ -17,16 +17,13 @@ limitations under the License.
 package ebiten
 
 type UI interface {
-	Start(widht, height, scale int, title string) (Canvas, error)
+	Start(widht, height, scale int, title string) error
 	DoEvents()
 	Terminate()
+	Draw(drawer GraphicsContextDrawer) error
+	IsClosed() bool
 }
 
 type GraphicsContextDrawer interface {
 	Draw(d GraphicsContext) error
 }
-
-type Canvas interface {
-	Draw(drawer GraphicsContextDrawer) error
-	IsClosed() bool
-}