[v3 windows] Support irregular shaped windows. Centered option.

v3/pkg/application/options_webview_window.go

@@ -23,7 +23,7 @@ type WebviewWindowOptions struct {
 	MaxWidth                        int
 	MaxHeight                       int
 	StartState                      WindowState
-	Mac                             MacWindow
+	Centered                        bool
 	BackgroundType                  BackgroundType
 	BackgroundColour                RGBA
 	HTML                            string
@@ -37,6 +37,7 @@ type WebviewWindowOptions struct {
 	EnableFraudulentWebsiteWarnings bool
 	Zoom                            float64
 	EnableDragAndDrop               bool
+	Mac                             MacWindow
 	Windows                         WindowsWindow
 }
 

v3/pkg/application/options_win.go

@@ -33,7 +33,8 @@ type WindowsWindow struct {
 	DisableFramelessWindowDecorations bool
 
 	// WindowMask is used to set the window shape. Use a PNG with an alpha channel to create a custom shape.
-	WindowMask []byte
+	WindowMask          []byte
+	WindowMaskDraggable bool
 }
 
 type Theme int

v3/pkg/application/webview_window.go

@@ -446,6 +446,7 @@ func (w *WebviewWindow) handleMessage(message string) {
 // Center centers the window on the screen
 func (w *WebviewWindow) Center() {
 	if w.impl == nil {
+		w.options.Centered = true
 		return
 	}
 	invokeSync(w.impl.center)

v3/pkg/application/webview_window_windows.go

@@ -185,6 +185,10 @@ func (w *windowsWebviewWindow) run() {
 		w.setWindowMask(options.Windows.WindowMask)
 	}
 
+	if options.Centered {
+		w.center()
+	}
+
 	w.setForeground()
 
 	if !options.Hidden {
@@ -649,7 +653,10 @@ func (w *windowsWebviewWindow) WndProc(msg uint32, wparam, lparam uintptr) uintp
 	if w.parent.options.Windows.WindowMask != nil {
 		switch msg {
 		case w32.WM_NCHITTEST:
-			return w32.HTCAPTION
+			if w.parent.options.Windows.WindowMaskDraggable {
+				return w32.HTCAPTION
+			}
+			return w32.HTCLIENT
 		}
 	}