[v3 Windows] Support application hide/show. Add WebviewWindow.IsVisible().

v3/STATUS.md

@@ -82,8 +82,8 @@ Webview Window Interface Methods
 | Feature | Windows | Linux | Mac | Notes |
 |---------|---------|-------|-----|-------|
 | Quit    |         |       | Y   |       |
-| Hide    |         |       | Y   |       |
-| Show    |         |       | Y   |       |
+| Hide    | Y       |       | Y   |       |
+| Show    | Y       |       | Y   |       |
 
 ### Dialogs
 

v3/pkg/application/application_windows.go

@@ -23,6 +23,10 @@ type windowsApp struct {
 	mainThreadID         w32.HANDLE
 	mainThreadWindowHWND w32.HWND
 
+	// Windows hidden by application.Hide()
+	hiddenWindows []*windowsWebviewWindow
+	focusedWindow w32.HWND
+
 	// system theme
 	isDarkMode bool
 }
@@ -38,9 +42,29 @@ func (m *windowsApp) getScreens() ([]*Screen, error) {
 }
 
 func (m *windowsApp) hide() {
+	// Get the current focussed window
+	m.focusedWindow = w32.GetForegroundWindow()
+
+	// Iterate over all windows and hide them if they aren't already hidden
+	for _, window := range m.windowMap {
+		if window.isVisible() {
+			// Add to hidden windows
+			m.hiddenWindows = append(m.hiddenWindows, window)
+			window.hide()
+		}
+	}
+	// Switch focus to the next application
+	hwndNext := w32.GetWindow(m.mainThreadWindowHWND, w32.GW_HWNDNEXT)
+	w32.SetForegroundWindow(hwndNext)
 }
 
 func (m *windowsApp) show() {
+	// Iterate over all windows and show them if they were previously hidden
+	for _, window := range m.hiddenWindows {
+		window.show()
+	}
+	// Show the foreground window
+	w32.SetForegroundWindow(m.focusedWindow)
 }
 
 func (m *windowsApp) on(eventID uint) {

v3/pkg/application/webview_window.go

@@ -53,7 +53,7 @@ type (
 		isMaximised() bool
 		isFullscreen() bool
 		isNormal() bool
-		disableSizeConstraints()
+		isVisible() bool
 		setFullscreenButtonEnabled(enabled bool)
 		show()
 		hide()
@@ -360,6 +360,14 @@ func (w *WebviewWindow) IsMinimised() bool {
 	return w.impl.isMinimised()
 }
 
+// IsVisible returns true if the window is visible
+func (w *WebviewWindow) IsVisible() bool {
+	if w.impl == nil {
+		return false
+	}
+	return w.impl.isVisible()
+}
+
 // IsMaximised returns true if the window is maximised
 func (w *WebviewWindow) IsMaximised() bool {
 	if w.impl == nil {

v3/pkg/application/webview_window_windows.go

@@ -260,6 +260,7 @@ func (w *windowsWebviewWindow) setPosition(x int, y int) {
 	w32.SetWindowPos(w.hwnd, w32.HWND_TOP, int(workRect.Left)+x, int(workRect.Top)+y, 0, 0, w32.SWP_NOSIZE)
 }
 
+// on is used to indicate that a particular event should be listened for
 func (w *windowsWebviewWindow) on(eventID uint) {
 	//TODO implement me
 	panic("implement me")
@@ -320,14 +321,13 @@ func (w *windowsWebviewWindow) isNormal() bool {
 	return !w.isMinimised() && !w.isMaximised() && !w.isFullscreen()
 }
 
-func (w *windowsWebviewWindow) disableSizeConstraints() {
-	//TODO implement me
-	panic("implement me")
+func (w *windowsWebviewWindow) isVisible() bool {
+	style := uint32(w32.GetWindowLong(w.hwnd, w32.GWL_STYLE))
+	return style&w32.WS_VISIBLE != 0
 }
 
-func (w *windowsWebviewWindow) setFullscreenButtonEnabled(enabled bool) {
-	//TODO implement me
-	panic("implement me")
+func (w *windowsWebviewWindow) setFullscreenButtonEnabled(_ bool) {
+	// Unused in Windows
 }
 
 func (w *windowsWebviewWindow) show() {

v3/pkg/w32/constants.go

@@ -276,6 +276,16 @@ const (
 	GWLP_USERDATA   = -21
 )
 
+const (
+	GW_HWNDFIRST    = 0
+	GW_HWNDLAST     = 1
+	GW_HWNDNEXT     = 2
+	GW_HWNDPREV     = 3
+	GW_OWNER        = 4
+	GW_CHILD        = 5
+	GW_ENABLEDPOPUP = 6
+)
+
 // Window style constants
 const (
 	WS_OVERLAPPED       = 0x00000000

v3/pkg/w32/user32.go

@@ -41,6 +41,7 @@ var (
 	procGetWindowText                 = moduser32.NewProc("GetWindowTextW")
 	procGetWindowRect                 = moduser32.NewProc("GetWindowRect")
 	procGetWindowInfo                 = moduser32.NewProc("GetWindowInfo")
+	procGetWindow                     = moduser32.NewProc("GetWindow")
 	procSetWindowCompositionAttribute = moduser32.NewProc("SetWindowCompositionAttribute")
 	procMoveWindow                    = moduser32.NewProc("MoveWindow")
 	procScreenToClient                = moduser32.NewProc("ScreenToClient")
@@ -415,6 +416,14 @@ func GetWindowInfo(hwnd HWND, info *WINDOWINFO) int {
 	return int(ret)
 }
 
+func GetWindow(hwnd HWND, cmd uint32) HWND {
+	ret, _, _ := procGetWindow.Call(
+		hwnd,
+		uintptr(cmd),
+	)
+	return HWND(ret)
+}
+
 func GetWindowText(hwnd HWND) string {
 	textLen := GetWindowTextLength(hwnd) + 1