ui: Implement SetWindowDecorated and IsWindowDecorated

Fixes #430.

examples/windowsize/main.go

@@ -18,6 +18,8 @@ package main
 
 import (
 	"bytes"
+	"errors"
+	"flag"
 	"fmt"
 	"image"
 	"image/color"
@@ -33,6 +35,10 @@ import (
 	"github.com/hajimehoshi/ebiten/inpututil"
 )
 
+var (
+	windowDecorated = flag.Bool("windowdecorated", true, "whether the window is decorated")
+)
+
 func init() {
 	rand.Seed(time.Now().UnixNano())
 }
@@ -67,7 +73,13 @@ func createRandomIconImage() image.Image {
 	return img
 }
 
+var terminated = errors.New("terminated")
+
 func update(screen *ebiten.Image) error {
+	if inpututil.IsKeyJustPressed(ebiten.KeyQ) {
+		return terminated
+	}
+
 	screenScale := ebiten.ScreenScale()
 	d := int(32 / screenScale)
 	screenWidth, screenHeight := screen.Size()
@@ -145,6 +157,7 @@ Press F key to switch the fullscreen state
 Press B key to switch the run-in-background state
 Press C key to switch the cursor visibility
 Press I key to change the window icon
+Press Q key to quit
 Cursor: (%d, %d)
 FPS: %0.2f`, x, y, ebiten.CurrentFPS())
 	ebitenutil.DebugPrint(screen, msg)
@@ -152,6 +165,8 @@ FPS: %0.2f`, x, y, ebiten.CurrentFPS())
 }
 
 func main() {
+	flag.Parse()
+
 	fmt.Printf("Device scale factor: %0.2f\n", ebiten.DeviceScaleFactor())
 
 	// Decode image from a byte slice instead of a file so that
@@ -171,7 +186,9 @@ func main() {
 
 	ebiten.SetWindowIcon([]image.Image{createRandomIconImage()})
 
-	if err := ebiten.Run(update, initScreenWidth, initScreenHeight, initScreenScale, "Window Size (Ebiten Demo)"); err != nil {
+	ebiten.SetWindowDecorated(*windowDecorated)
+
+	if err := ebiten.Run(update, initScreenWidth, initScreenHeight, initScreenScale, "Window Size (Ebiten Demo)"); err != nil && err != terminated {
 		log.Fatal(err)
 	}
 }

internal/ui/ui_glfw.go

@@ -48,9 +48,10 @@ type userInterface struct {
 	origPosY             int
 	runnableInBackground bool
 
-	initFullscreen    bool
-	initCursorVisible bool
-	initIconImages    []image.Image
+	initFullscreen      bool
+	initCursorVisible   bool
+	initWindowDecorated bool
+	initIconImages      []image.Image
 
 	funcs chan func()
 
@@ -59,10 +60,10 @@ type userInterface struct {
 
 var (
 	currentUI = &userInterface{
-		toChangeSize:      true,
-		origPosX:          -1,
-		origPosY:          -1,
-		initCursorVisible: true,
+		origPosX:            -1,
+		origPosY:            -1,
+		initCursorVisible:   true,
+		initWindowDecorated: true,
 	}
 	currentUIInitialized = make(chan struct{})
 )
@@ -80,6 +81,12 @@ func initialize() error {
 	glfw.WindowHint(glfw.ContextVersionMajor, 2)
 	glfw.WindowHint(glfw.ContextVersionMinor, 1)
 
+	decorated := glfw.False
+	if currentUI.isInitWindowDecorated() {
+		decorated = glfw.True
+	}
+	glfw.WindowHint(glfw.Decorated, decorated)
+
 	// As start, create an window with temporary size to create OpenGL context thread.
 	window, err := glfw.CreateWindow(16, 16, "", nil, nil)
 	if err != nil {
@@ -99,6 +106,7 @@ func initialize() error {
 		currentUI.window.SetIcon(i)
 	}
 	currentUI.window.SetInputMode(glfw.CursorMode, mode)
+
 	currentUI.window.SetInputMode(glfw.StickyMouseButtonsMode, glfw.True)
 	currentUI.window.SetInputMode(glfw.StickyKeysMode, glfw.True)
 	return nil
@@ -167,6 +175,19 @@ func (u *userInterface) setInitCursorVisible(visible bool) {
 	u.m.Unlock()
 }
 
+func (u *userInterface) isInitWindowDecorated() bool {
+	u.m.Lock()
+	v := u.initWindowDecorated
+	u.m.Unlock()
+	return v
+}
+
+func (u *userInterface) setInitWindowDecorated(decorated bool) {
+	u.m.Lock()
+	u.initWindowDecorated = decorated
+	u.m.Unlock()
+}
+
 func (u *userInterface) isRunnableInBackground() bool {
 	u.m.Lock()
 	v := u.runnableInBackground
@@ -369,6 +390,40 @@ func SetCursorVisible(visible bool) {
 	})
 }
 
+func IsWindowDecorated() bool {
+	u := currentUI
+	if !u.isRunning() {
+		return u.isInitWindowDecorated()
+	}
+	v := false
+	_ = currentUI.runOnMainThread(func() error {
+		v = currentUI.window.GetAttrib(glfw.Decorated) == glfw.True
+		return nil
+	})
+	return v
+}
+
+func SetWindowDecorated(decorated bool) {
+	u := currentUI
+	if !u.isRunning() {
+		u.setInitWindowDecorated(decorated)
+		return
+	}
+
+	panic("ui: SetWindowDecorated can't be called after Run so far.")
+
+	// TODO: Now SetAttrib doesn't exist on GLFW 3.2. Revisit later.
+	// If SetAttrib exists, the implementation would be:
+	//
+	//     _ = currentUI.runOnMainThread(func() error {
+	//         v := glfw.False
+	//         if decorated {
+	//             v = glfw.True
+	//         }
+	//     currentUI.window.SetAttrib(glfw.Decorated, v)
+	//     return nil
+}
+
 func Run(width, height int, scale float64, title string, g GraphicsContext) error {
 	<-currentUIInitialized
 

internal/ui/ui_js.go

@@ -98,6 +98,14 @@ func SetWindowIcon(iconImages []image.Image) {
 	// Do nothing
 }
 
+func IsWindowDecorated() bool {
+	return false
+}
+
+func SetWindowDecorated(decorated bool) {
+	// Do nothing
+}
+
 func (u *userInterface) getScale() float64 {
 	if !u.fullscreen {
 		return u.scale

internal/ui/ui_mobile.go

@@ -172,12 +172,15 @@ func SetCursorVisible(visible bool) {
 	// Do nothing
 }
 
+func IsFullscreen() bool {
+	return false
+}
+
 func SetFullscreen(fullscreen bool) {
 	// Do nothing
 }
 
-func IsFullscreen() bool {
-	// Do nothing
+func IsRunnableInBackground() bool {
 	return false
 }
 
@@ -185,12 +188,15 @@ func SetRunnableInBackground(runnableInBackground bool) {
 	// Do nothing
 }
 
-func IsRunnableInBackground() bool {
+func SetWindowIcon(iconImages []image.Image) {
 	// Do nothing
+}
+
+func IsWindowDecorated() bool {
 	return false
 }
 
-func SetWindowIcon(iconImages []image.Image) {
+func SetWindowDecorated(decorated bool) {
 	// Do nothing
 }
 

run.go

@@ -246,13 +246,34 @@ func SetFullscreen(fullscreen bool) {
 	ui.SetFullscreen(fullscreen)
 }
 
-// IsRunnableInBackground returns a boolean value indicating whether the game runs even in background.
+// IsRunnableInBackground returns a boolean value indicating whether
+// the game runs even in background.
 //
 // This function is concurrent-safe.
 func IsRunnableInBackground() bool {
 	return ui.IsRunnableInBackground()
 }
 
+// SetWindowDecorated sets the state if the window is decorated.
+//
+// SetWindowDecorated works only on desktops.
+// SetWindowDecorated does nothing on other platforms.
+//
+// SetWindowDecorated panics if SetWindowDecorated is called after Run.
+//
+// This function is concurrent-safe.
+func SetWindowDecorated(decorated bool) {
+	ui.SetWindowDecorated(decorated)
+}
+
+// IsWindowDecorated returns a boolean value indicating whether
+// the window is decorated.
+//
+// This function is concurrent-safe.
+func IsWindowDecorated() bool {
+	return ui.IsWindowDecorated()
+}
+
 // SetRunnableInBackground sets the state if the game runs even in background.
 //
 // If the given value is true, the game runs in background e.g. when losing focus.