[gtk] inspector: Avoid grabs for inspecting

[Matthias Clasen <matthiasc src gnome org>]

commit 9861887f1a41f43c834dc4d75ddba8c5de7ad11c
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 23 23:06:00 2019 -0500

    inspector: Avoid grabs for inspecting
    
    Instead of using a grab on a GtkInvisible, use
    a hook in the GTK event propagation machinery to
    get events.
    
    The only downside of this approach is that we
    lose the crosshair cursor. But we get rid of
    the last use of GtkInvisible.

 gtk/gtkmain.c                  |   4 ++
 gtk/inspector/inspect-button.c | 139 ++++++++++++-----------------------------
 gtk/inspector/window.c         |  26 ++++++++
 gtk/inspector/window.h         |   3 +-
 4 files changed, 72 insertions(+), 100 deletions(-)
---
diff --git a/gtk/gtkmain.c b/gtk/gtkmain.c
index eb60808d78..8aa278e9eb 100644
--- a/gtk/gtkmain.c
+++ b/gtk/gtkmain.c
@@ -134,6 +134,7 @@
 #include "gtkroot.h"
 
 #include "a11y/gtkaccessibility.h"
+#include "inspector/window.h"
 
 static GtkWindowGroup *gtk_main_get_window_group (GtkWidget   *widget);
 
@@ -1730,6 +1731,9 @@ gtk_main_do_event (GdkEvent *event)
   GdkDevice *device;
   GList *tmp_list;
 
+  if (gtk_inspector_handle_event (event))
+    return;
+
   /* Find the widget which got the event. We store the widget
    * in the user_data field of GdkSurface's. Ignore the event
    * if we don't have a widget for it.
diff --git a/gtk/inspector/inspect-button.c b/gtk/inspector/inspect-button.c
index 6b28299e8e..d34629d163 100644
--- a/gtk/inspector/inspect-button.c
+++ b/gtk/inspector/inspect-button.c
@@ -31,7 +31,6 @@
 
 #include "gtkstack.h"
 #include "gtkmain.h"
-#include "gtkinvisibleprivate.h"
 #include "gtkwidgetprivate.h"
 #include "gtkgesturemultipress.h"
 #include "gtkeventcontrollermotion.h"
@@ -95,9 +94,8 @@ select_widget (GtkInspectorWindow *iw,
 }
 
 static void
-on_inspect_widget (GtkWidget          *button,
-                   GdkEvent           *event,
-                   GtkInspectorWindow *iw)
+on_inspect_widget (GtkInspectorWindow *iw,
+                   GdkEvent           *event)
 {
   GtkWidget *widget;
 
@@ -179,126 +177,69 @@ reemphasize_window (GtkWidget *window)
     gdk_surface_raise (gtk_widget_get_surface (window));
 }
 
+static gboolean handle_event (GtkInspectorWindow *iw, GdkEvent *event);
+
 static void
-property_query_pressed (GtkGestureMultiPress *gesture,
-                        guint                 n_press,
-                        gdouble               x,
-                        gdouble               y,
-                        GtkInspectorWindow   *iw)
+handle_button_event (GtkInspectorWindow *iw,
+                     GdkEvent           *event)
 {
-  GdkEvent *event;
-
-  gtk_grab_remove (iw->invisible);
-  if (iw->grab_seat)
-    {
-      gdk_seat_ungrab (iw->grab_seat);
-      iw->grab_seat = NULL;
-    }
-
+  g_signal_handlers_disconnect_by_func (iw, handle_event, NULL);
   reemphasize_window (GTK_WIDGET (iw));
+  on_inspect_widget (iw, event);
+}
 
-  event = gtk_get_current_event ();
-  on_inspect_widget (iw->invisible, event, iw);
-  g_object_unref (event);
-
-  gtk_widget_destroy (iw->invisible);
-  iw->invisible = NULL;
+static void
+handle_motion_event (GtkInspectorWindow *iw,
+                     GdkEvent           *event)
+{
+  on_highlight_widget (NULL, event, iw);
 }
 
 static void
-property_query_motion (GtkEventControllerMotion *controller,
-                       gdouble                   x,
-                       gdouble                   y,
-                       GtkInspectorWindow       *iw)
+handle_key_event (GtkInspectorWindow *iw,
+                  GdkEvent           *event)
 {
-  GdkEvent *event;
+  guint keyval = 0;
 
-  event = gtk_get_current_event ();
-  on_highlight_widget (iw->invisible, event, iw);
-  g_object_unref (event);
+  gdk_event_get_keyval (event, &keyval);
+  if (keyval == GDK_KEY_Escape)
+    {
+      g_signal_handlers_disconnect_by_func (iw, handle_event, NULL);
+      reemphasize_window (GTK_WIDGET (iw));
+      clear_flash (iw);
+    }
 }
 
 static gboolean
-property_query_key (GtkEventControllerKey *key,
-                    guint                  keyval,
-                    guint                  keycode,
-                    GdkModifierType        modifiers,
-                    GtkInspectorWindow    *iw)
+handle_event (GtkInspectorWindow *iw, GdkEvent *event)
 {
-  if (keyval == GDK_KEY_Escape)
+  switch ((int)gdk_event_get_event_type (event))
     {
-      gtk_grab_remove (iw->invisible);
-      if (iw->grab_seat)
-        {
-          gdk_seat_ungrab (iw->grab_seat);
-          iw->grab_seat = NULL;
-        }
-      reemphasize_window (GTK_WIDGET (iw));
+    case GDK_KEY_PRESS:
+    case GDK_KEY_RELEASE:
+      handle_key_event (iw, event);
+      break;
 
-      clear_flash (iw);
+    case GDK_MOTION_NOTIFY:
+      handle_motion_event (iw, event);
+      break;
 
-      gtk_widget_destroy (iw->invisible);
-      iw->invisible = NULL;
+    case GDK_BUTTON_PRESS:
+    case GDK_BUTTON_RELEASE:
+      handle_button_event (iw, event);
+      break;
 
-      return TRUE;
+    default:;
     }
 
-  return FALSE;
-}
-
-static void
-prepare_inspect_func (GdkSeat   *seat,
-                      GdkSurface *surface,
-                      gpointer   user_data)
-{
-  gdk_surface_show (surface);
+  return TRUE;
 }
 
-
 void
 gtk_inspector_on_inspect (GtkWidget          *button,
                           GtkInspectorWindow *iw)
 {
-  GdkDisplay *display;
-  GdkCursor *cursor;
-  GdkGrabStatus status;
-  GtkEventController *controller;
-  GdkSeat *seat;
-
-  if (!iw->invisible)
-    {
-      iw->invisible = gtk_invisible_new_for_display (gdk_display_get_default ());
-      gtk_widget_realize (iw->invisible);
-      gtk_widget_show (iw->invisible);
-    }
-
-  display = gdk_display_get_default ();
-  cursor = gdk_cursor_new_from_name ("crosshair", NULL);
-  seat = gdk_display_get_default_seat (display);
-  status = gdk_seat_grab (seat,
-                          gtk_widget_get_surface (iw->invisible),
-                          GDK_SEAT_CAPABILITY_ALL_POINTING, TRUE,
-                          cursor, NULL, prepare_inspect_func, NULL);
-  g_object_unref (cursor);
-  if (status == GDK_GRAB_SUCCESS)
-    iw->grab_seat = seat;
-
-  controller = GTK_EVENT_CONTROLLER (gtk_gesture_multi_press_new ());
-  g_signal_connect (controller, "pressed",
-                   G_CALLBACK (property_query_pressed), iw);
-  gtk_widget_add_controller (iw->invisible, controller);
-
-  controller = gtk_event_controller_motion_new ();
-  g_signal_connect (controller, "motion",
-                    G_CALLBACK (property_query_motion), iw);
-  gtk_widget_add_controller (iw->invisible, controller);
-
-  controller = GTK_EVENT_CONTROLLER (gtk_event_controller_key_new ());
-  g_signal_connect (controller, "key-pressed",
-                    G_CALLBACK (property_query_key), iw);
-  gtk_widget_add_controller (iw->invisible, controller);
-
-  gtk_grab_add (GTK_WIDGET (iw->invisible));
+  g_signal_connect (iw, "event", G_CALLBACK (handle_event), NULL);
   deemphasize_window (GTK_WIDGET (iw));
 }
 
diff --git a/gtk/inspector/window.c b/gtk/inspector/window.c
index 9bdced31e4..191bbb90b3 100644
--- a/gtk/inspector/window.c
+++ b/gtk/inspector/window.c
@@ -286,6 +286,17 @@ gtk_inspector_window_class_init (GtkInspectorWindowClass *klass)
   object_class->constructed = gtk_inspector_window_constructed;
   widget_class->realize = gtk_inspector_window_realize;
 
+  g_signal_new (g_intern_static_string ("event"),
+                G_OBJECT_CLASS_TYPE (object_class),
+                G_SIGNAL_RUN_LAST,
+                0,
+                g_signal_accumulator_true_handled,
+                NULL,
+                NULL,
+                G_TYPE_BOOLEAN,
+                1,
+                GDK_TYPE_EVENT);
+
   gtk_widget_class_set_template_from_resource (widget_class, "/org/gtk/libgtk/inspector/window.ui");
 
   gtk_widget_class_bind_template_child (widget_class, GtkInspectorWindow, top_stack);
@@ -468,4 +479,19 @@ gtk_inspector_is_recording (GtkWidget *widget)
   return gtk_inspector_recorder_is_recording (GTK_INSPECTOR_RECORDER (iw->widget_recorder));
 }
 
+gboolean
+gtk_inspector_handle_event (GdkEvent *event)
+{
+  GtkInspectorWindow *iw;
+  gboolean handled = FALSE;
+
+  iw = gtk_inspector_window_get_for_display (gdk_event_get_display (event));
+  if (iw == NULL)
+    return FALSE;
+
+  g_signal_emit_by_name (iw, "event", event, &handled);
+
+  return handled;
+}
+
 // vim: set et sw=2 ts=2:
diff --git a/gtk/inspector/window.h b/gtk/inspector/window.h
index ed1adfa3df..6e3c5f6647 100644
--- a/gtk/inspector/window.h
+++ b/gtk/inspector/window.h
@@ -72,7 +72,6 @@ typedef struct
   GtkWidget *controllers;
   GtkWidget *magnifier;
 
-  GtkWidget *invisible;
   GtkWidget *selected_widget;
 
   GList *extra_pages;
@@ -117,6 +116,8 @@ GskRenderNode *         gtk_inspector_prepare_render
                                                                                  GdkSurface             
*surface,
                                                                                  const cairo_region_t   
*region,
                                                                                  GskRenderNode          
*node);
+gboolean                gtk_inspector_handle_event                              (GdkEvent               
*event);
+                                                                                
 
 G_END_DECLS