gtk/texthandle: Handle events on parent surface's native

In wayland, popup positioning and event handling are doubly async.
This makes it unreliable to figure out parent surface coordinates
out of the popup position and the events received. This results in
jumpy text handles there.

The best way to deal with parent surface coordinates is to handle
the events there. Make the handles transparent to input, and make
the drag gesture be set up on the parent widget's native.

The gesture is set up in the capture phase, setting it on the native
(as opposed to the parent widget) achieves a feeling similar to it
being a distinct surface, as it should take precedence over other
gestures in the emission chain (e.g. scrolledwindows).

As everything is in parent widget's native's coordinates, the drag
handles become smooth again.

diff --git a/gtk/gtktexthandle.c b/gtk/gtktexthandle.c
index b5b645a7c91f1cff3fe4734f9855b3fb05b55dc5..b900d699eb045786efd4e7f0f9572626339ff012 100644 (file)
--- a/gtk/gtktexthandle.c
+++ b/gtk/gtktexthandle.c
@@ -44,9 +44,10 @@ struct _GtkTextHandle
 {
   GtkWidget parent_instance;
 
-  GtkWidget *parent;
   GdkSurface *surface;
   GskRenderer *renderer;
+  GtkEventController *controller;
+  GtkWidget *controller_widget;
 
   GdkRectangle pointing_to;
   GtkBorder border;
@@ -61,6 +62,19 @@ struct _GtkTextHandle
 
 static void gtk_text_handle_native_interface_init (GtkNativeInterface *iface);
 
+static void handle_drag_begin (GtkGestureDrag *gesture,
+                               double          x,
+                               double          y,
+                               GtkTextHandle  *handle);
+static void handle_drag_update (GtkGestureDrag *gesture,
+                                double          offset_x,
+                                double          offset_y,
+                                GtkWidget      *widget);
+static void handle_drag_end (GtkGestureDrag *gesture,
+                             double          offset_x,
+                             double          offset_y,
+                             GtkTextHandle  *handle);
+
 G_DEFINE_TYPE_WITH_CODE (GtkTextHandle, gtk_text_handle, GTK_TYPE_WIDGET,
                          G_IMPLEMENT_INTERFACE (GTK_TYPE_NATIVE,
                                                 gtk_text_handle_native_interface_init))
@@ -185,15 +199,6 @@ surface_render (GdkSurface     *surface,
   return TRUE;
 }
 
-static gboolean
-surface_event (GdkSurface    *surface,
-               GdkEvent      *event,
-               GtkTextHandle *handle)
-{
-  gtk_main_do_event (event);
-  return TRUE;
-}
-
 static void
 surface_mapped_changed (GtkWidget *widget)
 {
@@ -226,11 +231,11 @@ gtk_text_handle_realize (GtkWidget *widget)
 
   handle->surface = gdk_surface_new_popup (parent_surface, FALSE);
   gdk_surface_set_widget (handle->surface, widget);
+  gdk_surface_set_input_region (handle->surface, cairo_region_create ());
 
   g_signal_connect_swapped (handle->surface, "notify::mapped",
                             G_CALLBACK (surface_mapped_changed), widget);
   g_signal_connect (handle->surface, "render", G_CALLBACK (surface_render), widget);
-  g_signal_connect (handle->surface, "event", G_CALLBACK (surface_event), widget);
 
   GTK_WIDGET_CLASS (gtk_text_handle_parent_class)->realize (widget);
 
@@ -248,7 +253,6 @@ gtk_text_handle_unrealize (GtkWidget *widget)
   g_clear_object (&handle->renderer);
 
   g_signal_handlers_disconnect_by_func (handle->surface, surface_render, widget);
-  g_signal_handlers_disconnect_by_func (handle->surface, surface_event, widget);
   g_signal_handlers_disconnect_by_func (handle->surface, surface_mapped_changed, widget);
 
   gdk_surface_set_widget (handle->surface, NULL);
@@ -256,6 +260,28 @@ gtk_text_handle_unrealize (GtkWidget *widget)
   g_clear_object (&handle->surface);
 }
 
+static void
+text_handle_set_up_gesture (GtkTextHandle *handle)
+{
+  GtkNative *native;
+
+  /* The drag gesture is hooked on the parent native */
+  native = gtk_widget_get_native (gtk_widget_get_parent (GTK_WIDGET (handle)));
+  handle->controller_widget = GTK_WIDGET (native);
+
+  handle->controller = GTK_EVENT_CONTROLLER (gtk_gesture_drag_new ());
+  gtk_event_controller_set_propagation_phase (handle->controller,
+                                              GTK_PHASE_CAPTURE);
+  g_signal_connect (handle->controller, "drag-begin",
+                    G_CALLBACK (handle_drag_begin), handle);
+  g_signal_connect (handle->controller, "drag-update",
+                    G_CALLBACK (handle_drag_update), handle);
+  g_signal_connect (handle->controller, "drag-end",
+                    G_CALLBACK (handle_drag_end), handle);
+
+  gtk_widget_add_controller (handle->controller_widget, handle->controller);
+}
+
 static void
 gtk_text_handle_map (GtkWidget *widget)
 {
@@ -264,7 +290,10 @@ gtk_text_handle_map (GtkWidget *widget)
   GTK_WIDGET_CLASS (gtk_text_handle_parent_class)->map (widget);
 
   if (handle->has_point)
-    gtk_text_handle_present_surface (handle);
+    {
+      gtk_text_handle_present_surface (handle);
+      text_handle_set_up_gesture (handle);
+    }
 }
 
 static void
@@ -274,6 +303,14 @@ gtk_text_handle_unmap (GtkWidget *widget)
 
   GTK_WIDGET_CLASS (gtk_text_handle_parent_class)->unmap (widget);
   gdk_surface_hide (handle->surface);
+
+  if (handle->controller_widget)
+    {
+      gtk_widget_remove_controller (handle->controller_widget,
+                                    handle->controller);
+      handle->controller_widget = NULL;
+      handle->controller = NULL;
+    }
 }
 
 static void
@@ -330,26 +367,67 @@ gtk_text_handle_class_init (GtkTextHandleClass *klass)
   gtk_widget_class_set_css_name (widget_class, I_("cursor-handle"));
 }
 
+/* Relative to pointing_to x/y */
 static void
-handle_drag_begin (GtkGestureDrag *gesture,
-                   double          x,
-                   double          y,
-                   GtkTextHandle  *handle)
+handle_get_input_extents (GtkTextHandle *handle,
+                          GtkBorder     *border)
 {
-  GtkWidget *widget;
-
-  widget = gtk_event_controller_get_widget (GTK_EVENT_CONTROLLER (gesture));
+  GtkWidget *widget = GTK_WIDGET (handle);
 
   if (handle->role == GTK_TEXT_HANDLE_ROLE_CURSOR)
-    x -= gtk_widget_get_width (widget) / 2;
+    {
+      border->left = (-gtk_widget_get_width (widget) / 2) - handle->border.left;
+      border->right = (gtk_widget_get_width (widget) / 2) + handle->border.right;
+    }
   else if ((handle->role == GTK_TEXT_HANDLE_ROLE_SELECTION_END &&
             gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL) ||
            (handle->role == GTK_TEXT_HANDLE_ROLE_SELECTION_START &&
             gtk_widget_get_direction (widget) != GTK_TEXT_DIR_RTL))
-    x -= gtk_widget_get_width (widget);
+    {
+      border->left = -gtk_widget_get_width (widget) - handle->border.left;
+      border->right = handle->border.right;
+    }
+  else
+    {
+      border->left = -handle->border.left;
+      border->right = gtk_widget_get_width (widget) + handle->border.right;
+    }
 
-  y += handle->border.top / 2;
+  border->top = - handle->border.top;
+  border->bottom = gtk_widget_get_height (widget) + handle->border.bottom;
+}
+
+static void
+handle_drag_begin (GtkGestureDrag *gesture,
+                   double          x,
+                   double          y,
+                   GtkTextHandle  *handle)
+{
+  GtkBorder input_extents;
+  double widget_x, widget_y;
+
+  x -= handle->pointing_to.x;
+  y -= handle->pointing_to.y;
+
+  /* Figure out if the coordinates fall into the handle input area, coordinates
+   * are relative to the parent widget.
+   */
+  handle_get_input_extents (handle, &input_extents);
+  gtk_widget_translate_coordinates (handle->controller_widget,
+                                    gtk_widget_get_parent (GTK_WIDGET (handle)),
+                                    x, y, &widget_x, &widget_y);
+
+  if (widget_x < input_extents.left || widget_x >= input_extents.right ||
+      widget_y < input_extents.top || widget_y >= input_extents.bottom)
+    {
+      gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_DENIED);
+      return;
+    }
 
+  gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_CLAIMED);
+  /* Store untranslated coordinates here, so ::update does not need
+   * an extra translation
+   */
   handle->dx = x;
   handle->dy = y;
   handle->dragged = TRUE;
@@ -368,19 +446,8 @@ handle_drag_update (GtkGestureDrag *gesture,
 
   gtk_gesture_drag_get_start_point (gesture, &start_x, &start_y);
 
-  x = handle->pointing_to.x + handle->pointing_to.width / 2 +
-    start_x + offset_x - handle->dx;
-  y = handle->pointing_to.y + handle->pointing_to.height +
-    start_y + offset_y - handle->dy;
-
-  if (handle->role == GTK_TEXT_HANDLE_ROLE_CURSOR)
-    x -= gtk_widget_get_width (widget) / 2;
-  else if ((handle->role == GTK_TEXT_HANDLE_ROLE_SELECTION_END &&
-            gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL) ||
-           (handle->role == GTK_TEXT_HANDLE_ROLE_SELECTION_START &&
-            gtk_widget_get_direction (widget) != GTK_TEXT_DIR_RTL))
-    x -= gtk_widget_get_width (widget);
-
+  x = start_x + offset_x - handle->dx;
+  y = start_y + offset_y - handle->dy;
   g_signal_emit (widget, signals[HANDLE_DRAGGED], 0, x, y);
 }
 
@@ -390,7 +457,15 @@ handle_drag_end (GtkGestureDrag *gesture,
                  double          offset_y,
                  GtkTextHandle  *handle)
 {
-  g_signal_emit (handle, signals[DRAG_FINISHED], 0);
+  GdkEventSequence *sequence;
+  GtkEventSequenceState state;
+
+  sequence = gtk_gesture_single_get_current_sequence (GTK_GESTURE_SINGLE (gesture));
+  state = gtk_gesture_get_sequence_state (GTK_GESTURE (gesture), sequence);
+
+  if (state == GTK_EVENT_SEQUENCE_CLAIMED)
+    g_signal_emit (handle, signals[DRAG_FINISHED], 0);
+
   handle->dragged = FALSE;
 }
 
@@ -422,20 +497,9 @@ gtk_text_handle_update_for_role (GtkTextHandle *handle)
 }
 
 static void
-gtk_text_handle_init (GtkTextHandle *widget)
+gtk_text_handle_init (GtkTextHandle *handle)
 {
-  GtkEventController *controller;
-
-  controller = GTK_EVENT_CONTROLLER (gtk_gesture_drag_new ());
-  g_signal_connect (controller, "drag-begin",
-                    G_CALLBACK (handle_drag_begin), widget);
-  g_signal_connect (controller, "drag-update",
-                    G_CALLBACK (handle_drag_update), widget);
-  g_signal_connect (controller, "drag-end",
-                    G_CALLBACK (handle_drag_end), widget);
-  gtk_widget_add_controller (GTK_WIDGET (widget), controller);
-
-  gtk_text_handle_update_for_role (GTK_TEXT_HANDLE (widget));
+  gtk_text_handle_update_for_role (handle);
 }
 
 GtkTextHandle *