Support for minimum and maximum window sizes (#612)

* add support for minimum and maximum window sizes

* attempt to fix windows

* bug fixes

* support min/max window sizes on Linux and Windows

* fix min/max window sizes on Linux

* formatting and comments

* fixes Windows DPI issue, clamps width/height values to min/max

* App can't go into full screen when max size is set for Mac

* fixed Linux maximum width/height on window maximize

* Revert "fixed Linux maximum width/height on window maximize"

This reverts commit 3f7ba8b264.

The fix glitches on PopOS

Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

config.go

@@ -31,6 +31,18 @@ type AppConfig struct {
 	// Indicates whether your app should be resizable
 	Resizable bool
 
+	// Minimum width of a resizable window. If set, MinHeight should also be set.
+	MinWidth int
+
+	// Minimum height of a resizable window. If set, MinWidth should also be set.
+	MinHeight int
+
+	// Maximum width of a resizable window. If set, MaxHeight should also be set.
+	MaxWidth int
+
+	// Maximum height of a resizable window. If set, MaxWidth should also be set.
+	MaxHeight int
+
 	// Indicated if the devtools should be disabled
 	DisableInspector bool
 }
@@ -65,6 +77,26 @@ func (a *AppConfig) GetResizable() bool {
 	return a.Resizable
 }
 
+// GetMinWidth returns the minimum width of the window
+func (a *AppConfig) GetMinWidth() int {
+	return a.MinWidth
+}
+
+// GetMinHeight returns the minimum height of the window
+func (a *AppConfig) GetMinHeight() int {
+	return a.MinHeight
+}
+
+// GetMaxWidth returns the maximum width of the window
+func (a *AppConfig) GetMaxWidth() int {
+	return a.MaxWidth
+}
+
+// GetMaxHeight returns the maximum height of the window
+func (a *AppConfig) GetMaxHeight() int {
+	return a.MaxHeight
+}
+
 // GetDisableInspector returns true if the inspector should be disabled
 func (a *AppConfig) GetDisableInspector() bool {
 	return a.DisableInspector
@@ -115,6 +147,23 @@ func (a *AppConfig) merge(in *AppConfig) error {
 	if in.Height != 0 {
 		a.Height = in.Height
 	}
+
+	if in.MinWidth != 0 {
+		a.MinWidth = in.MinWidth
+	}
+
+	if in.MinHeight != 0 {
+		a.MinHeight = in.MinHeight
+	}
+
+	if in.MaxWidth != 0 {
+		a.MaxWidth = in.MaxWidth
+	}
+
+	if in.MaxHeight != 0 {
+		a.MaxHeight = in.MaxHeight
+	}
+
 	a.Resizable = in.Resizable
 	a.DisableInspector = in.DisableInspector
 
@@ -127,6 +176,10 @@ func newConfig(userConfig *AppConfig) (*AppConfig, error) {
 		Width:     800,
 		Height:    600,
 		Resizable: true,
+		MinWidth:  -1,
+		MinHeight: -1,
+		MaxWidth:  -1,
+		MaxHeight: -1,
 		Title:     "My Wails App",
 		Colour:    "#FFF", // White by default
 		HTML:      defaultHTML,

lib/interfaces/appconfig.go

@@ -5,6 +5,10 @@ type AppConfig interface {
 	GetWidth() int
 	GetHeight() int
 	GetTitle() string
+	GetMinWidth() int
+	GetMinHeight() int
+	GetMaxWidth() int
+	GetMaxHeight() int
 	GetResizable() bool
 	GetHTML() string
 	GetDisableInspector() bool

lib/interfaces/renderer.go

@@ -22,6 +22,10 @@ type Renderer interface {
 
 	// Window Runtime
 	SetColour(string) error
+
+	SetMinSize(width, height int)
+	SetMaxSize(width, height int)
+
 	Fullscreen()
 	UnFullscreen()
 	SetTitle(title string)

lib/interfaces/runtime.go

@@ -1,4 +1,4 @@
 package interfaces
 
 // Runtime interface
-type Runtime interface {}
+type Runtime interface{}

lib/renderer/bridge/bridge.go

@@ -186,6 +186,18 @@ func (h *Bridge) SetColour(colour string) error {
 	return nil
 }
 
+// SetMinSize is unsupported for Bridge but required
+// for the Renderer interface
+func (h *Bridge) SetMinSize(width, height int) {
+	h.log.Warn("SetMinSize() unsupported in bridge mode")
+}
+
+// SetMaxSize is unsupported for Bridge but required
+// for the Renderer interface
+func (h *Bridge) SetMaxSize(width, height int) {
+	h.log.Warn("SetMaxSize() unsupported in bridge mode")
+}
+
 // Fullscreen is unsupported for Bridge but required
 // for the Renderer interface
 func (h *Bridge) Fullscreen() {

lib/renderer/webview.go

@@ -29,6 +29,8 @@ type WebView struct {
 	config       interfaces.AppConfig
 	eventManager interfaces.EventManager
 	bindingCache []string
+	
+	maximumSizeSet bool
 }
 
 // NewWebView returns a new WebView struct
@@ -52,10 +54,37 @@ func (w *WebView) Initialise(config interfaces.AppConfig, ipc interfaces.IPCMana
 	// Save the config
 	w.config = config
 
+	width := config.GetWidth()
+	height := config.GetHeight()
+
+	// Clamp width and height
+	minWidth, minHeight := config.GetMinWidth(), config.GetMinHeight()
+	maxWidth, maxHeight := config.GetMaxWidth(), config.GetMaxHeight()
+	setMinSize := minWidth != -1 && minHeight != -1
+	setMaxSize := maxWidth != -1 && maxHeight != -1
+
+	if setMinSize {
+		if width < minWidth {
+			width = minWidth
+		}
+		if height < minHeight {
+			height = minHeight
+		}
+	}
+
+	if setMaxSize {
+		if width > maxWidth {
+			width = maxWidth
+		}
+		if height > maxHeight {
+			height = maxHeight
+		}
+	}
+
 	// Create the WebView instance
 	w.window = wv.NewWebview(wv.Settings{
-		Width:     config.GetWidth(),
+		Width:     width,
-		Height:    config.GetHeight(),
+		Height:    height,
 		Title:     config.GetTitle(),
 		Resizable: config.GetResizable(),
 		URL:       config.GetHTML(),
@@ -64,6 +93,16 @@ func (w *WebView) Initialise(config interfaces.AppConfig, ipc interfaces.IPCMana
 			w.ipc.Dispatch(message, w.callback)
 		},
 	})
+		fmt.Println("Control")
+
+	// Set minimum and maximum sizes
+	if setMinSize {
+		w.SetMinSize(minWidth, minHeight)
+	}
+	if setMaxSize {
+		w.SetMaxSize(maxWidth, maxHeight)
+		fmt.Println("Max")
+	}
 
 	// SignalManager.OnExit(w.Exit)
 
@@ -74,6 +113,7 @@ func (w *WebView) Initialise(config interfaces.AppConfig, ipc interfaces.IPCMana
 	}
 
 	w.log.Info("Initialised")
+
 	return nil
 }
 
@@ -353,11 +393,37 @@ func (w *WebView) NotifyEvent(event *messages.EventData) error {
 	return w.evalJS(message)
 }
 
+// SetMinSize sets the minimum size of a resizable window
+func (w *WebView) SetMinSize(width, height int) {
+	if w.config.GetResizable() == false {
+		w.log.Warn("Cannot call SetMinSize() - App.Resizable = false")
+		return
+	}
+	w.window.Dispatch(func() {
+		w.window.SetMinSize(width, height)
+	})
+}
+
+// SetMaxSize sets the maximum size of a resizable window
+func (w *WebView) SetMaxSize(width, height int) {
+	if w.config.GetResizable() == false {
+		w.log.Warn("Cannot call SetMaxSize() - App.Resizable = false")
+		return
+	}
+	w.maximumSizeSet = true
+	w.window.Dispatch(func() {
+		w.window.SetMaxSize(width, height)
+	})
+}
+
 // Fullscreen makes the main window go fullscreen
 func (w *WebView) Fullscreen() {
 	if w.config.GetResizable() == false {
 		w.log.Warn("Cannot call Fullscreen() - App.Resizable = false")
 		return
+	} else if w.maximumSizeSet {
+		w.log.Warn("Cannot call Fullscreen() - Maximum size of window set")
+		return
 	}
 	w.window.Dispatch(func() {
 		w.window.SetFullscreen(true)

lib/renderer/webview/webview.go

@@ -69,6 +69,14 @@ static inline void CgoWebViewFocus(void *w) {
 	webview_focus((struct webview *)w);
 }
 
+static inline void CgoWebViewMinSize(void *w, int width, int height) {
+	webview_minsize((struct webview *)w, width, height);
+}
+
+static inline void CgoWebViewMaxSize(void *w, int width, int height) {
+	webview_maxsize((struct webview *)w, width, height);
+}
+
 static inline void CgoWebViewSetFullscreen(void *w, int fullscreen) {
 	webview_set_fullscreen((struct webview *)w, fullscreen);
 }
@@ -178,6 +186,12 @@ type WebView interface {
 	// Focus() puts the main window into focus
 	Focus()
 
+	// SetMinSize() sets the minimum size of the window
+	SetMinSize(width, height int)
+
+	// SetMaxSize() sets the maximum size of the window
+	SetMaxSize(width, height int)
+
 	// SetFullscreen() controls window full-screen mode. This method must be
 	// called from the main thread only. See Dispatch() for more details.
 	SetFullscreen(fullscreen bool)
@@ -319,6 +333,14 @@ func (w *webview) Focus() {
 	C.CgoWebViewFocus(w.w)
 }
 
+func (w *webview) SetMinSize(width, height int) {
+	C.CgoWebViewMinSize(w.w, C.int(width), C.int(height))
+}
+
+func (w *webview) SetMaxSize(width, height int) {
+	C.CgoWebViewMaxSize(w.w, C.int(width), C.int(height))
+}
+
 func (w *webview) SetFullscreen(fullscreen bool) {
 	C.CgoWebViewSetFullscreen(w.w, C.int(boolToInt(fullscreen)))
 }

lib/renderer/webview/webview.h

@@ -54,6 +54,11 @@ extern "C"
     int ready;
     int js_busy;
     int should_exit;
+    
+    int min_width;
+    int min_height;
+    int max_width;
+    int max_height;
   };
 #elif defined(WEBVIEW_WINAPI)
 #define CINTERFACE
@@ -75,6 +80,11 @@ struct webview_priv
   DWORD saved_style;
   DWORD saved_ex_style;
   RECT saved_rect;
+
+  int min_width;
+  int min_height;
+  int max_width;
+  int max_height;
 };
 #elif defined(WEBVIEW_COCOA)
 #import <Cocoa/Cocoa.h>
@@ -169,6 +179,8 @@ struct webview_priv
   WEBVIEW_API int webview_inject_css(struct webview *w, const char *css);
   WEBVIEW_API void webview_set_title(struct webview *w, const char *title);
   WEBVIEW_API void webview_focus(struct webview *w);
+  WEBVIEW_API void webview_minsize(struct webview *w, int width, int height);  
+  WEBVIEW_API void webview_maxsize(struct webview *w, int width, int height);
   WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen);
   WEBVIEW_API void webview_set_color(struct webview *w, uint8_t r, uint8_t g,
                                      uint8_t b, uint8_t a);
@@ -330,6 +342,12 @@ struct webview_priv
     w->priv.should_exit = 0;
     w->priv.queue = g_async_queue_new();
     w->priv.window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+    
+    w->priv.min_width = -1;
+    w->priv.min_height = -1;
+    w->priv.max_width = -1;
+    w->priv.max_height = -1;
+    
     gtk_window_set_title(GTK_WINDOW(w->priv.window), w->title);
 
     if (w->resizable)
@@ -402,6 +420,44 @@ struct webview_priv
     gtk_window_present(GTK_WINDOW(w->priv.window));
   }
 
+  WEBVIEW_API void webview_minsize(struct webview *w, int width, int height) {
+  
+    w->priv.min_width = width;
+    w->priv.min_height = height;
+
+    GdkGeometry hints;
+    GdkWindowHints usedHints = (GdkWindowHints) GDK_HINT_MIN_SIZE;
+    
+    hints.min_width = w->priv.min_width;
+    hints.min_height = w->priv.min_height;
+    if (w->priv.max_width != -1) {
+      hints.max_width = w->priv.max_width;
+      hints.max_height = w->priv.max_height;
+      usedHints = (GdkWindowHints)(GDK_HINT_MIN_SIZE | GDK_HINT_MAX_SIZE);
+    }
+    
+    gtk_window_set_geometry_hints(GTK_WINDOW(w->priv.window), w->priv.window, &hints, usedHints);
+  }
+
+  WEBVIEW_API void webview_maxsize(struct webview *w, int width, int height) {
+    
+    w->priv.max_width = width;
+    w->priv.max_height = height;
+  
+    GdkGeometry hints;
+    GdkWindowHints usedHints = (GdkWindowHints) GDK_HINT_MAX_SIZE;
+    
+    if (w->priv.min_width != -1) {
+      hints.min_width = w->priv.min_width;
+      hints.min_height = w->priv.min_height;
+      usedHints = (GdkWindowHints)(GDK_HINT_MIN_SIZE | GDK_HINT_MAX_SIZE);
+    }
+    hints.max_width = w->priv.max_width;
+    hints.max_height = w->priv.max_height;
+    
+    gtk_window_set_geometry_hints(GTK_WINDOW(w->priv.window), w->priv.window, &hints, usedHints);
+  }
+
   WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen)
   {
     if (fullscreen)
@@ -1337,7 +1393,39 @@ struct webview_priv
     case WM_CREATE:
       w = (struct webview *)((CREATESTRUCT *)lParam)->lpCreateParams;
       w->priv.hwnd = hwnd;
+
       return EmbedBrowserObject(w);
+    case WM_GETMINMAXINFO:
+    {
+      if (w != NULL) {
+        // get pixel density 
+        HDC hDC = GetDC(NULL);
+        double DPIScaleX = GetDeviceCaps(hDC, 88)/96.0;
+        double DPIScaleY = GetDeviceCaps(hDC, 90)/96.0;
+        ReleaseDC(NULL, hDC);
+      	
+        RECT rcClient, rcWind;
+        POINT ptDiff;
+        GetClientRect(hwnd, &rcClient);
+        GetWindowRect(hwnd, &rcWind);
+
+        int widthExtra = (rcWind.right - rcWind.left) - rcClient.right;
+        int heightExtra = (rcWind.bottom - rcWind.top) - rcClient.bottom;
+
+        LPMINMAXINFO lpMMI = (LPMINMAXINFO)lParam;
+      
+        if (w->priv.min_width != -1) {
+          lpMMI->ptMinTrackSize.x = w->priv.min_width * DPIScaleX + widthExtra;
+          lpMMI->ptMinTrackSize.y = w->priv.min_height * DPIScaleY + heightExtra;
+        }
+        if (w->priv.max_width != -1) {
+          lpMMI->ptMaxTrackSize.x = w->priv.max_width * DPIScaleX + widthExtra;
+          lpMMI->ptMaxTrackSize.y = w->priv.max_height * DPIScaleY + heightExtra;
+        }
+      }
+      
+      return 0;
+    }
     case WM_DESTROY:
       UnEmbedBrowserObject(w);
       PostQuitMessage(0);
@@ -1402,6 +1490,9 @@ struct webview_priv
 
   WEBVIEW_API int webview_init(struct webview *w)
   {
+    w->priv.min_width = -1;
+    w->priv.max_width = -1;
+
     WNDCLASSEX wc;
     HINSTANCE hInstance;
     DWORD style;
@@ -1652,6 +1743,16 @@ struct webview_priv
     SetFocus(w->priv.hwnd);
   }
 
+  WEBVIEW_API void webview_minsize(struct webview *w, int width, int height) {
+    w->priv.min_width = width;
+    w->priv.min_height = height;
+  }
+
+  WEBVIEW_API void webview_maxsize(struct webview *w, int width, int height) {
+    w->priv.max_width = width;
+    w->priv.max_height = height;
+  }
+
   WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen)
   {
     if (w->priv.is_fullscreen == !!fullscreen)
@@ -2224,6 +2325,25 @@ struct webview_priv
     [w->priv.window makeKeyWindow];
   }
   
+  WEBVIEW_API void webview_minsize(struct webview *w, int width, int height) {
+    NSSize size;
+    size.width = width;
+    size.height = height;
+    [w->priv.window setMinSize:size];
+  }
+  
+  WEBVIEW_API void webview_maxsize(struct webview *w, int width, int height) {
+    NSSize size;
+    size.width = width;
+    size.height = height;
+    [w->priv.window setMaxSize:size];
+    
+    [w->priv.window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenAuxiliary|NSWindowCollectionBehaviorFullScreenNone|NSWindowCollectionBehaviorFullScreenDisallowsTiling];
+       
+    NSButton *button = [w->priv.window standardWindowButton:NSWindowZoomButton];
+    [button setEnabled: NO];
+  }
+  
   WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen)
   {
     int b = ((([w->priv.window styleMask] & NSWindowStyleMaskFullScreen) ==

package-lock.json

@@ -0,0 +1,3 @@
+{
+  "lockfileVersion": 1
+}

runtime/window.go

@@ -67,6 +67,16 @@ func (r *Window) SetColour(colour string) error {
 	return r.renderer.SetColour(colour)
 }
 
+// SetMinSize sets the minimum size of a resizable window
+func (r *Window) SetMinSize(width, height int) {
+	r.renderer.SetMinSize(width, height)
+}
+
+// SetMaxSize sets the maximum size of a resizable window
+func (r *Window) SetMaxSize(width, height int) {
+	r.renderer.SetMaxSize(width, height)
+}
+
 // Fullscreen makes the window fullscreen
 func (r *Window) Fullscreen() {
 	r.renderer.Fullscreen()