[linux] Support drag.

v2/internal/frontend/desktop/linux/frontend.go

@@ -349,10 +349,7 @@ func (f *Frontend) Notify(name string, data ...interface{}) {
 func (f *Frontend) processMessage(message string) {
 	if message == "drag" {
 		//if !f.mainWindow.IsFullScreen() {
-		err := f.startDrag()
+		f.startDrag()
-		if err != nil {
-			f.logger.Error(err.Error())
-		}
 		//}
 		return
 	}
@@ -379,12 +376,10 @@ func (f *Frontend) Callback(message string) {
 	f.ExecJS(`window.wails.Callback(` + strconv.Quote(message) + `);`)
 }
 
-func (f *Frontend) startDrag() error {
+func (f *Frontend) startDrag() {
-	//if !w32.ReleaseCapture() {
+	f.dispatch(func() {
-	//	return fmt.Errorf("unable to release mouse capture")
+		f.mainWindow.StartDrag()
-	//}
+	})
-	//w32.SendMessage(f.gtkWindow.Handle(), w32.WM_NCLBUTTONDOWN, w32.HTCAPTION, 0)
-	return nil
 }
 
 func (f *Frontend) ExecJS(js string) {
@@ -403,20 +398,6 @@ func (f *Frontend) dispatch(fn func()) {
 	C.gtkDispatch(C.int(id))
 }
 
-//func (f *Frontend) navigationCompleted(sender *edge.ICoreWebView2, args *edge.ICoreWebView2NavigationCompletedEventArgs) {
-//	if f.frontendOptions.OnDomReady != nil {
-//		go f.frontendOptions.OnDomReady(f.ctx)
-//	}
-//
-//	// If you want to start hidden, return
-//	if f.frontendOptions.StartHidden {
-//		return
-//	}
-//
-//	f.gtkWindow.Show()
-//
-//}
-
 var messageBuffer = make(chan string, 100)
 
 //export processMessage

v2/internal/frontend/desktop/linux/window.go

@@ -105,6 +105,43 @@ ulong setupInvokeSignal(void* contentManager) {
 	return g_signal_connect((WebKitUserContentManager*)contentManager, "script-message-received::external", G_CALLBACK(sendMessageToBackend), NULL);
 }
 
+// These are the x,y & time of the last mouse down event
+// It's used for window dragging
+float xroot = 0.0f;
+float yroot = 0.0f;
+int dragTime = -1;
+
+gboolean buttonPress(GtkWidget *widget, GdkEventButton *event, void* dummy)
+{
+	if( event == NULL ) {
+		xroot = yroot = 0.0f;
+		dragTime = -1;
+		return FALSE;
+	}
+	if (event->type == GDK_BUTTON_PRESS && event->button == 1)
+    {
+        xroot = event->x_root;
+        yroot = event->y_root;
+        dragTime = event->time;
+    }
+    return FALSE;
+}
+
+gboolean buttonRelease(GtkWidget *widget, GdkEventButton *event, void* dummy)
+{
+    if (event == NULL || (event->type == GDK_BUTTON_RELEASE && event->button == 1))
+    {
+		xroot = yroot = 0.0f;
+		dragTime = -1;
+    }
+    return FALSE;
+}
+
+void connectButtons(void* webview, ulong* pressed, ulong* released) {
+	*pressed = g_signal_connect(WEBKIT_WEB_VIEW(webview), "button-press-event", G_CALLBACK(buttonPress), NULL);
+	*released = g_signal_connect(WEBKIT_WEB_VIEW(webview), "button-release-event", G_CALLBACK(buttonRelease), NULL);
+}
+
 extern void processURLRequest(WebKitURISchemeRequest *request);
 
 GtkWidget* setupWebview(void* contentManager, GtkWindow* window) {
@@ -122,10 +159,19 @@ void devtoolsEnabled(void* webview, int enabled) {
 	webkit_settings_set_enable_developer_extras(settings, genabled);
 }
 
-
 void loadIndex(void* webview) {
 	webkit_web_view_load_uri(WEBKIT_WEB_VIEW(webview), "wails:///");
 }
+
+static void startDrag(void *webview, GtkWindow* mainwindow)
+{
+    // Ignore non-toplevel widgets
+    GtkWidget *window = gtk_widget_get_toplevel(GTK_WIDGET(webview));
+    if (!GTK_IS_WINDOW(window)) return;
+
+    gtk_window_begin_move_drag(mainwindow, 1, xroot, yroot, dragTime);
+}
+
 */
 import "C"
 import (
@@ -147,6 +193,8 @@ type Window struct {
 	contentManager      unsafe.Pointer
 	webview             unsafe.Pointer
 	signalInvoke        C.ulong
+	signalMousePressed  C.ulong
+	signalMouseReleased C.ulong
 }
 
 func NewWindow(appoptions *options.App, debug bool) *Window {
@@ -165,8 +213,12 @@ func NewWindow(appoptions *options.App, debug bool) *Window {
 	defer C.free(unsafe.Pointer(external))
 	C.webkit_user_content_manager_register_script_message_handler(result.cWebKitUserContentManager(), external)
 	result.signalInvoke = C.setupInvokeSignal(result.contentManager)
+
 	webview := C.setupWebview(result.contentManager, result.asGTKWindow())
 	result.webview = unsafe.Pointer(webview)
+	buttonPressedName := C.CString("button-press-event")
+	defer C.free(unsafe.Pointer(buttonPressedName))
+	C.connectButtons(unsafe.Pointer(webview), &result.signalMousePressed, &result.signalMouseReleased)
 
 	if debug {
 		C.devtoolsEnabled(unsafe.Pointer(webview), C.int(1))
@@ -340,3 +392,7 @@ func (w *Window) ExecJS(js string) {
 	defer C.free(unsafe.Pointer(script))
 	C.webkit_web_view_run_javascript((*C.WebKitWebView)(w.webview), script, nil, nil, nil)
 }
+
+func (w *Window) StartDrag() {
+	C.startDrag(w.webview, w.asGTKWindow())
+}