Add SetScreenScale (#115)

example/windowsize/main.go

@@ -15,8 +15,10 @@
 package main
 
 import (
+	"fmt"
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
+	"image/color"
 	_ "image/jpeg"
 	"log"
 )
@@ -24,17 +26,20 @@ import (
 const (
 	initScreenWidth  = 320
 	initScreenHeight = 240
+	initScreenScale  = 2
 )
 
 var (
 	gophersImage *ebiten.Image
 	screenWidth  = initScreenWidth
 	screenHeight = initScreenHeight
+	screenScale  = initScreenScale
 	keyStates    = map[ebiten.Key]int{
 		ebiten.KeyUp:    0,
 		ebiten.KeyDown:  0,
 		ebiten.KeyLeft:  0,
 		ebiten.KeyRight: 0,
+		ebiten.KeyS:     0,
 	}
 )
 
@@ -51,16 +56,25 @@ func update(screen *ebiten.Image) error {
 		screenHeight += 16
 	}
 	if keyStates[ebiten.KeyDown] == 1 {
-		screenHeight -= 16
+		if 16 < screenHeight {
+			screenHeight -= 16
+		}
 	}
 	if keyStates[ebiten.KeyLeft] == 1 {
-		screenWidth -= 16
+		if 16 < screenWidth {
+			screenWidth -= 16
+		}
 	}
 	if keyStates[ebiten.KeyRight] == 1 {
 		screenWidth += 16
 	}
+	if keyStates[ebiten.KeyS] == 1 {
+		screenScale = 3 - screenScale // Swap 1 and 2
+	}
 	ebiten.SetScreenSize(screenWidth, screenHeight)
+	ebiten.SetScreenScale(screenScale)
 
+	screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff})
 	w, h := gophersImage.Size()
 	w2, h2 := screen.Size()
 	op := &ebiten.DrawImageOptions{}
@@ -69,7 +83,11 @@ func update(screen *ebiten.Image) error {
 		return err
 	}
 
-	ebitenutil.DebugPrint(screen, "Press arrow keys")
+	x, y := ebiten.CursorPosition()
+	msg := fmt.Sprintf(`Press arrow keys to change the window size
+Press S key to change the window scale
+Cursor: (%d, %d)`, x, y)
+	ebitenutil.DebugPrint(screen, msg)
 	return nil
 }
 
@@ -79,7 +97,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := ebiten.Run(update, initScreenWidth, initScreenHeight, 2, "Window Size (Ebiten Demo)"); err != nil {
+	if err := ebiten.Run(update, initScreenWidth, initScreenHeight, initScreenScale, "Window Size (Ebiten Demo)"); err != nil {
 		log.Fatal(err)
 	}
 }

exp/audio/internal/audio.go

@@ -33,6 +33,8 @@ type channel struct {
 var MaxChannel = 32
 
 var channels = make([]*channel, MaxChannel)
+
+// NOTE: In GopherJS, sync.Mutex blocks a function and requires gopherjs:blocking comments.
 var channelsLock sync.Mutex
 
 func init() {

internal/ui/ui_glfw.go

@@ -93,6 +93,11 @@ func SetScreenSize(width, height int) (bool, int) {
 	return result, currentUI.actualScale
 }
 
+func SetScreenScale(scale int) (bool, int) {
+	result := currentUI.setScreenSize(currentUI.width, currentUI.height, scale)
+	return result, currentUI.actualScale
+}
+
 type userInterface struct {
 	window      *glfw.Window
 	width       int

internal/ui/ui_js.go

@@ -52,6 +52,13 @@ func SetScreenSize(width, height int) (bool, int) {
 	return result, actualScale
 }
 
+func SetScreenScale(scale int) (bool, int) {
+	width, height := currentUI.size()
+	result := currentUI.setScreenSize(width, height, scale)
+	actualScale := canvas.Get("dataset").Get("ebitenActualScale").Int()
+	return result, actualScale
+}
+
 var canvas js.Object
 
 type userInterface struct{}
@@ -228,15 +235,21 @@ func (u *userInterface) start(width, height, scale int, title string) (actualSca
 	return actualScale, nil
 }
 
-func (*userInterface) setScreenSize(width, height, scale int) bool {
+func (*userInterface) size() (width, height int) {
 	a := canvas.Get("dataset").Get("ebitenActualScale").Int()
-	if a != 0 {
-		w := canvas.Get("width").Int() / a
-		h := canvas.Get("height").Int() / a
-		s := canvas.Get("dataset").Get("ebitenScale").Int()
-		if w == width && h == height && s == scale {
-			return false
-		}
+	if a == 0 {
+		return
+	}
+	width = canvas.Get("width").Int() / a
+	height = canvas.Get("height").Int() / a
+	return
+}
+
+func (u *userInterface) setScreenSize(width, height, scale int) bool {
+	w, h := u.size()
+	s := canvas.Get("dataset").Get("ebitenScale").Int()
+	if w == width && h == height && s == scale {
+		return false
 	}
 
 	actualScale := scale * devicePixelRatio()

run.go

@@ -25,6 +25,7 @@ var runContext = &struct {
 	fps             float64
 	newScreenWidth  int
 	newScreenHeight int
+	newScreenScale  int
 }{}
 
 // CurrentFPS returns the current number of frames per second.
@@ -43,6 +44,9 @@ func CurrentFPS() float64 {
 // If you need to care about time, you need to check current time every time f is called.
 func Run(f func(*Image) error, width, height, scale int, title string) error {
 	runContext.running = true
+	defer func() {
+		runContext.running = false
+	}()
 
 	actualScale, err := ui.Start(width, height, scale, title)
 	if err != nil {
@@ -58,8 +62,20 @@ func Run(f func(*Image) error, width, height, scale int, title string) error {
 	frames := 0
 	t := time.Now().UnixNano()
 	for {
-		if 0 < runContext.newScreenWidth || 0 < runContext.newScreenHeight {
-			changed, actualScale := ui.SetScreenSize(runContext.newScreenWidth, runContext.newScreenHeight)
+		if 0 < runContext.newScreenWidth || 0 < runContext.newScreenHeight || 0 < runContext.newScreenScale {
+			changed := false
+			actualScale := 0
+			if 0 < runContext.newScreenWidth || 0 < runContext.newScreenHeight {
+				c, a := ui.SetScreenSize(runContext.newScreenWidth, runContext.newScreenHeight)
+				changed = changed || c
+				actualScale = a
+			}
+			if 0 < runContext.newScreenScale {
+				c, a := ui.SetScreenScale(runContext.newScreenScale)
+				changed = changed || c
+				// actualScale of SetScreenState is more reliable than one of SetScreenSize
+				actualScale = a
+			}
 			if changed {
 				w, h := runContext.newScreenWidth, runContext.newScreenHeight
 				if err := graphicsContext.setSize(w, h, actualScale); err != nil {
@@ -69,6 +85,7 @@ func Run(f func(*Image) error, width, height, scale int, title string) error {
 		}
 		runContext.newScreenWidth = 0
 		runContext.newScreenHeight = 0
+		runContext.newScreenScale = 0
 
 		if err := ui.DoEvents(); err != nil {
 			return err
@@ -110,10 +127,22 @@ func SetScreenSize(width, height int) {
 	if !runContext.running {
 		panic("SetScreenSize must be called during Run")
 	}
+	if width <= 0 || height <= 0 {
+		panic("width and height must be positive")
+	}
 	runContext.newScreenWidth = width
 	runContext.newScreenHeight = height
 }
 
-// TODO: Create SetScreenPosition (for GLFW)
+// SetScreenSize changes the scale of the screen.
+func SetScreenScale(scale int) {
+	if !runContext.running {
+		panic("SetScreenScale must be called during Run")
+	}
+	if scale <= 0 {
+		panic("scale must be positive")
+	}
+	runContext.newScreenScale = scale
+}
 
-// TODO: Create SetScreenScale
+// TODO: Create SetScreenPosition (for GLFW)