ebiten: Add {Set,}WindowSizeLimits

Closes #1385

examples/windowsize/main.go

@@ -25,6 +25,7 @@ import (
 	"log"
 	"math"
 	"math/rand"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -45,6 +46,8 @@ var (
 	flagMaximize          = flag.Bool("maximize", false, "maximize the window")
 	flagVsync             = flag.Bool("vsync", true, "enable vsync")
 	flagInitFocused       = flag.Bool("initfocused", true, "whether the window is focused on start")
+	flagMinWindowSize     = flag.String("minwindowsize", "", "minimum window size (e.g., 100x200)")
+	flagMaxWindowSize     = flag.String("maxwindowsize", "", "maximium window size (e.g., 1920x1080)")
 )
 
 func init() {
@@ -280,6 +283,7 @@ func (g *game) Draw(screen *ebiten.Image) {
 	screen.DrawImage(gophersImage, op)
 
 	wx, wy := ebiten.WindowPosition()
+	minw, minh, maxw, maxh := ebiten.WindowSizeLimits()
 	cx, cy := ebiten.CursorPosition()
 	tpsStr := "Uncapped"
 	if t := ebiten.MaxTPS(); t != ebiten.UncappedTPS {
@@ -319,10 +323,11 @@ func (g *game) Draw(screen *ebiten.Image) {
 %s
 IsFocused?: %s
 Windows Position: (%d, %d)
+Window size limitation: (%d, %d) - (%d, %d)
 Cursor: (%d, %d)
 TPS: Current: %0.2f / Max: %s
 FPS: %0.2f
-Device Scale Factor: %0.2f`, msgM, msgR, fg, wx, wy, cx, cy, ebiten.CurrentTPS(), tpsStr, ebiten.CurrentFPS(), ebiten.DeviceScaleFactor())
+Device Scale Factor: %0.2f`, msgM, msgR, fg, wx, wy, minw, minh, maxw, maxh, cx, cy, ebiten.CurrentTPS(), tpsStr, ebiten.CurrentFPS(), ebiten.DeviceScaleFactor())
 	ebitenutil.DebugPrint(screen, msg)
 }
 
@@ -400,6 +405,21 @@ func main() {
 		ebiten.SetRunnableOnUnfocused(true)
 	}
 
+	minw, minh, maxw, maxh := -1, -1, -1, -1
+	reSize := regexp.MustCompile(`^(\d+)x(\d+)$`)
+	if m := reSize.FindStringSubmatch(*flagMinWindowSize); m != nil {
+		minw, _ = strconv.Atoi(m[1])
+		minh, _ = strconv.Atoi(m[2])
+	}
+	if m := reSize.FindStringSubmatch(*flagMaxWindowSize); m != nil {
+		maxw, _ = strconv.Atoi(m[1])
+		maxh, _ = strconv.Atoi(m[2])
+	}
+	if minw >= 0 && minh >= 0 && maxw >= 0 && maxh >= 0 {
+		ebiten.SetWindowSizeLimits(minw, minh, maxw, maxh)
+		ebiten.SetWindowResizable(true)
+	}
+
 	const title = "Window Size (Ebiten Demo)"
 	ww := int(float64(g.width) * initScreenScale)
 	wh := int(float64(g.height) * initScreenScale)

internal/driver/ui.go

@@ -78,6 +78,8 @@ type Window interface {
 
 	Size() (int, int)
 	SetSize(width, height int)
+	SizeLimits() (minw, minh, maxw, maxh int)
+	SetSizeLimits(minw, minh, maxw, maxh int)
 
 	IsFloating() bool
 	SetFloating(floating bool)

internal/glfw/const.go

@@ -34,8 +34,9 @@ type (
 )
 
 const (
-	False = 0
-	True  = 1
+	DontCare = -1
+	False    = 0
+	True     = 1
 )
 
 const (

internal/glfw/glfw_notwindows.go

@@ -109,10 +109,6 @@ func (w *Window) GetAttrib(attrib Hint) int {
 	return w.w.GetAttrib(glfw.Hint(attrib))
 }
 
-func (w *Window) SetAttrib(attrib Hint, value int) {
-	w.w.SetAttrib(glfw.Hint(attrib), value)
-}
-
 func (w *Window) GetCursorPos() (x, y float64) {
 	return w.w.GetCursorPos()
 }
@@ -161,6 +157,10 @@ func (w *Window) Restore() {
 	w.w.Restore()
 }
 
+func (w *Window) SetAttrib(attrib Hint, value int) {
+	w.w.SetAttrib(glfw.Hint(attrib), value)
+}
+
 func (w *Window) SetCharModsCallback(cbfun CharModsCallback) (previous CharModsCallback) {
 	var gcb glfw.CharModsCallback
 	if cbfun != nil {
@@ -215,6 +215,10 @@ func (w *Window) SetSizeCallback(cbfun SizeCallback) (previous SizeCallback) {
 	return prev
 }
 
+func (w *Window) SetSizeLimits(minw, minh, maxw, maxh int) {
+	w.w.SetSizeLimits(minw, minh, maxw, maxh)
+}
+
 func (w *Window) SetIcon(images []image.Image) {
 	w.w.SetIcon(images)
 }

internal/uidriver/glfw/ui.go

@@ -54,8 +54,12 @@ type UserInterface struct {
 
 	// windowWidth and windowHeight represents a window size.
 	// The unit is device-dependent pixels.
-	windowWidth  int
-	windowHeight int
+	windowWidth     int
+	windowHeight    int
+	minWindowWidth  int
+	minWindowHeight int
+	maxWindowWidth  int
+	maxWindowHeight int
 
 	running             uint32
 	toChangeSize        bool
@@ -110,6 +114,10 @@ const (
 var (
 	theUI = &UserInterface{
 		runnableOnUnfocused:     true,
+		minWindowWidth:          glfw.DontCare,
+		minWindowHeight:         glfw.DontCare,
+		maxWindowWidth:          glfw.DontCare,
+		maxWindowHeight:         glfw.DontCare,
 		origPosX:                invalidPos,
 		origPosY:                invalidPos,
 		initVsync:               true,
@@ -235,6 +243,25 @@ func (u *UserInterface) setRunning(running bool) {
 	}
 }
 
+func (u *UserInterface) getWindowSizeLimits() (minw, minh, maxw, maxh int) {
+	u.m.RLock()
+	defer u.m.RUnlock()
+	return u.minWindowWidth, u.minWindowHeight, u.maxWindowWidth, u.maxWindowHeight
+}
+
+func (u *UserInterface) setWindowSizeLimits(minw, minh, maxw, maxh int) bool {
+	u.m.RLock()
+	defer u.m.RUnlock()
+	if u.minWindowWidth == minw && u.minWindowHeight == minh && u.maxWindowWidth == maxw && u.maxWindowHeight == maxh {
+		return false
+	}
+	u.minWindowWidth = minw
+	u.minWindowHeight = minh
+	u.maxWindowWidth = maxw
+	u.maxWindowHeight = maxh
+	return true
+}
+
 func (u *UserInterface) getInitTitle() string {
 	u.m.RLock()
 	v := u.initTitle
@@ -782,6 +809,8 @@ func (u *UserInterface) init() error {
 		setPosition()
 	}
 
+	u.updateWindowSizeLimits()
+
 	// Maximizing a window requires a proper size and position. Call Maximize here (#1117).
 	if u.isInitWindowMaximized() {
 		u.window.Maximize()
@@ -973,8 +1002,45 @@ func (u *UserInterface) swapBuffers() {
 	}
 }
 
+// updateWindowSizeLimits must be called from the main thread.
+func (u *UserInterface) updateWindowSizeLimits() {
+	minw, minh, maxw, maxh := u.getWindowSizeLimits()
+	if minw < 0 {
+		minw = glfw.DontCare
+	}
+	if minh < 0 {
+		minh = glfw.DontCare
+	}
+	if maxw < 0 {
+		maxw = glfw.DontCare
+	}
+	if maxh < 0 {
+		maxh = glfw.DontCare
+	}
+	u.window.SetSizeLimits(minw, minh, maxw, maxh)
+}
+
+func (u *UserInterface) adjustWindowSizeBasedOnSizeLimits(width, height int) (int, int) {
+	minw, minh, maxw, maxh := u.getWindowSizeLimits()
+	if minw >= 0 && width < minw {
+		width = minw
+	}
+	if minh >= 0 && height < minh {
+		height = minh
+	}
+	if maxw >= 0 && width > maxw {
+		width = maxw
+	}
+	if maxh >= 0 && height > maxh {
+		height = maxh
+	}
+	return width, height
+}
+
 // setWindowSize must be called from the main thread.
 func (u *UserInterface) setWindowSize(width, height int, fullscreen bool) {
+	width, height = u.adjustWindowSizeBasedOnSizeLimits(width, height)
+
 	if u.windowWidth == width && u.windowHeight == height && u.isFullscreen() == fullscreen && u.lastDeviceScaleFactor == u.deviceScaleFactor() {
 		return
 	}
@@ -1045,6 +1111,8 @@ func (u *UserInterface) setWindowSize(width, height int, fullscreen bool) {
 					// TODO: This should return an error.
 					panic(fmt.Sprintf("glfw: failed to recreate window: %v", err))
 				}
+				// Reset the size limits explicitly.
+				u.updateWindowSizeLimits()
 				u.window.Show()
 				windowRecreated = true
 			}

internal/uidriver/glfw/window.go

@@ -228,7 +228,8 @@ func (w *window) setPosition(x, y int) {
 
 func (w *window) Size() (int, int) {
 	if !w.ui.isRunning() {
-		return w.ui.getInitWindowSize()
+		ww, wh := w.ui.getInitWindowSize()
+		return w.ui.adjustWindowSizeBasedOnSizeLimits(ww, wh)
 	}
 	ww := int(w.ui.fromGLFWPixel(float64(w.ui.windowWidth)))
 	wh := int(w.ui.fromGLFWPixel(float64(w.ui.windowHeight)))
@@ -248,6 +249,49 @@ func (w *window) SetSize(width, height int) {
 	})
 }
 
+func (w *window) SizeLimits() (minw, minh, maxw, maxh int) {
+	minw, minh, maxw, maxh = w.ui.getWindowSizeLimits()
+	if minw >= 0 {
+		minw = int(w.ui.fromGLFWPixel(float64(minw)))
+	}
+	if minh >= 0 {
+		minh = int(w.ui.fromGLFWPixel(float64(minh)))
+	}
+	if maxw >= 0 {
+		maxw = int(w.ui.fromGLFWPixel(float64(maxw)))
+	}
+	if maxh >= 0 {
+		maxh = int(w.ui.fromGLFWPixel(float64(maxh)))
+	}
+	return
+}
+
+func (w *window) SetSizeLimits(minw, minh, maxw, maxh int) {
+	if minw >= 0 {
+		minw = int(w.ui.toGLFWPixel(float64(minw)))
+	}
+	if minh >= 0 {
+		minh = int(w.ui.toGLFWPixel(float64(minh)))
+	}
+	if maxw >= 0 {
+		maxw = int(w.ui.toGLFWPixel(float64(maxw)))
+	}
+	if maxh >= 0 {
+		maxh = int(w.ui.toGLFWPixel(float64(maxh)))
+	}
+	if !w.ui.setWindowSizeLimits(minw, minh, maxw, maxh) {
+		return
+	}
+	if !w.ui.isRunning() {
+		return
+	}
+
+	_ = w.ui.t.Call(func() error {
+		w.ui.updateWindowSizeLimits()
+		return nil
+	})
+}
+
 func (w *window) SetIcon(iconImages []image.Image) {
 	// The icons are actually set at (*UserInterface).loop.
 	w.ui.setIconImages(iconImages)

window.go

@@ -235,6 +235,27 @@ func SetWindowSize(width, height int) {
 	}
 }
 
+// WindowSizeLimist returns the limitation of the window size on desktops.
+// A negative value indicates the size is not limited.
+//
+// WindowMaxSize is concurrent-safe.
+func WindowSizeLimits() (minw, minh, maxw, maxh int) {
+	if w := uiDriver().Window(); w != nil {
+		return w.SizeLimits()
+	}
+	return -1, -1, -1, -1
+}
+
+// SetWindowSizeLimits sets the limitation of the window size on desktops.
+// A negative value indicates the size is not limited.
+//
+// SetWindowMaxSize is concurrent-safe.
+func SetWindowSizeLimits(minw, minh, maxw, maxh int) {
+	if w := uiDriver().Window(); w != nil {
+		w.SetSizeLimits(minw, minh, maxw, maxh)
+	}
+}
+
 // IsWindowFloating reports whether the window is always shown above all the other windows.
 //
 // IsWindowFloating returns false on browsers and mobiles.