[gnome-photos] Handle asynchronous activation of PhotosTool instances

[Debarshi Ray <debarshir src gnome org>]

commit 91b146bdf0b8228ecdf245b21e08de4f74f20e9a
Author: Debarshi Ray <debarshir gnome org>
Date:   Thu Feb 11 10:57:58 2016 +0100

    Handle asynchronous activation of PhotosTool instances
    
    Some tools can be activated asynchronously. eg., PhotosToolCrop. We can
    not queue a draw until the entire activation step has finished.
    Otherwise, we will be asking the tool to draw while it is in an
    incoherent state. Therefore, add a new signal to let PhotosTool
    sub-classes indicate that they have finished activating.

 src/photos-preview-view.c |   33 +++++++++++++++++++++++++++------
 src/photos-tool-colors.c  |    2 ++
 src/photos-tool-crop.c    |   11 ++++++++---
 src/photos-tool-enhance.c |    4 +++-
 src/photos-tool-filters.c |    5 ++++-
 src/photos-tool.c         |   13 ++++++++++++-
 src/photos-tool.h         |    3 ++-
 7 files changed, 58 insertions(+), 13 deletions(-)
---
diff --git a/src/photos-preview-view.c b/src/photos-preview-view.c
index eba3fa5..fc2faba 100644
--- a/src/photos-preview-view.c
+++ b/src/photos-preview-view.c
@@ -430,6 +430,24 @@ photos_preview_view_sharpen (PhotosPreviewView *self, GVariant *parameter)
 
 
 static void
+photos_preview_view_tool_activated (PhotosTool *tool, gpointer user_data)
+{
+  PhotosPreviewView *self = PHOTOS_PREVIEW_VIEW (user_data);
+  GtkWidget *view_container;
+  GtkWidget *view;
+
+  g_return_if_fail (self->current_tool == NULL);
+
+  self->current_tool = tool;
+  g_object_add_weak_pointer (G_OBJECT (self->current_tool), (gpointer *) &self->current_tool);
+
+  view_container = gtk_stack_get_visible_child (GTK_STACK (self->stack));
+  view = photos_preview_view_get_view_from_view_container (view_container);
+  gtk_widget_queue_draw (view);
+}
+
+
+static void
 photos_preview_view_tool_changed (PhotosPreviewView *self, PhotosTool *tool)
 {
   GtkWidget *view_container;
@@ -442,24 +460,27 @@ photos_preview_view_tool_changed (PhotosPreviewView *self, PhotosTool *tool)
     {
       photos_tool_deactivate (self->current_tool);
       g_object_remove_weak_pointer (G_OBJECT (self->current_tool), (gpointer *) &self->current_tool);
+      g_signal_handlers_disconnect_by_func (self->current_tool, photos_preview_view_tool_activated, self);
       self->current_tool = NULL;
     }
 
   view_container = gtk_stack_get_visible_child (GTK_STACK (self->stack));
   view = photos_preview_view_get_view_from_view_container (view_container);
 
-  if (tool != NULL)
+  if (tool == NULL)
+    {
+      self->current_tool = NULL;
+      gtk_widget_queue_draw (view);
+    }
+  else
     {
       PhotosBaseItem *item;
 
-      self->current_tool = tool;
-      g_object_add_weak_pointer (G_OBJECT (self->current_tool), (gpointer *) &self->current_tool);
+      g_signal_connect_object (tool, "activated", G_CALLBACK (photos_preview_view_tool_activated), self, 0);
 
       item = PHOTOS_BASE_ITEM (photos_base_manager_get_active_object (self->item_mngr));
-      photos_tool_activate (self->current_tool, item, GEGL_GTK_VIEW (view));
+      photos_tool_activate (tool, item, GEGL_GTK_VIEW (view));
     }
-
-  gtk_widget_queue_draw (view);
 }
 
 
diff --git a/src/photos-tool-colors.c b/src/photos-tool-colors.c
index e4b11b2..98e9062 100644
--- a/src/photos-tool-colors.c
+++ b/src/photos-tool-colors.c
@@ -188,6 +188,8 @@ photos_tool_colors_activate (PhotosTool *tool, PhotosBaseItem *item, GeglGtkView
                                      photos_tool_colors_brightness_contrast_value_changed,
                                      self);
   g_signal_handlers_unblock_by_func (self->saturation_scale, photos_tool_colors_saturation_value_changed, 
self);
+
+  g_signal_emit_by_name (self, "activated");
 }
 
 
diff --git a/src/photos-tool-crop.c b/src/photos-tool-crop.c
index 7bd2a72..f62e877 100644
--- a/src/photos-tool-crop.c
+++ b/src/photos-tool-crop.c
@@ -912,6 +912,10 @@ photos_tool_crop_process (GObject *source_object, GAsyncResult *res, gpointer us
                                                     self,
                                                     G_CONNECT_SWAPPED);
 
+  self->activated = TRUE;
+  self->reset = FALSE;
+  g_signal_emit_by_name (self, "activated");
+
  out:
   gtk_widget_queue_draw (self->view);
   g_object_unref (self);
@@ -983,10 +987,11 @@ photos_tool_crop_activate (PhotosTool *tool, PhotosBaseItem *item, GeglGtkView *
                                                         G_CALLBACK (photos_tool_crop_size_allocate),
                                                         self,
                                                         G_CONNECT_SWAPPED);
-    }
 
-  self->activated = TRUE;
-  self->reset = FALSE;
+      self->activated = TRUE;
+      self->reset = FALSE;
+      g_signal_emit_by_name (self, "activated");
+    }
 }
 
 
diff --git a/src/photos-tool-enhance.c b/src/photos-tool-enhance.c
index 2b18372..c2e8e06 100644
--- a/src/photos-tool-enhance.c
+++ b/src/photos-tool-enhance.c
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2015 Red Hat, Inc.
+ * Copyright © 2015, 2016 Red Hat, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -144,6 +144,8 @@ photos_tool_enhance_activate (PhotosTool *tool, PhotosBaseItem *item, GeglGtkVie
   g_signal_handlers_block_by_func (self->sharpen_scale, photos_tool_enhance_sharpen_value_changed, self);
   gtk_range_set_value (GTK_RANGE (self->sharpen_scale), sharpen_scale);
   g_signal_handlers_unblock_by_func (self->sharpen_scale, photos_tool_enhance_sharpen_value_changed, self);
+
+  g_signal_emit_by_name (self, "activated");
 }
 
 
diff --git a/src/photos-tool-filters.c b/src/photos-tool-filters.c
index a5758a7..cef7e18 100644
--- a/src/photos-tool-filters.c
+++ b/src/photos-tool-filters.c
@@ -109,7 +109,7 @@ photos_tool_filters_activate (PhotosTool *tool, PhotosBaseItem *item, GeglGtkVie
   PhotosOperationInstaPreset preset;
 
   if (self->buttons == NULL || self->create_preview_id != 0)
-    return;
+    goto out;
 
   g_clear_object (&self->item);
   self->item = g_object_ref (item);
@@ -136,6 +136,9 @@ photos_tool_filters_activate (PhotosTool *tool, PhotosBaseItem *item, GeglGtkVie
             }
         }
     }
+
+ out:
+  g_signal_emit_by_name (self, "activated");
 }
 
 
diff --git a/src/photos-tool.c b/src/photos-tool.c
index c911e49..b22bdd9 100644
--- a/src/photos-tool.c
+++ b/src/photos-tool.c
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2015 Red Hat, Inc.
+ * Copyright © 2015, 2016 Red Hat, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -30,6 +30,7 @@
 
 enum
 {
+  ACTIVATED,
   HIDE_REQUESTED,
   LAST_SIGNAL
 };
@@ -88,6 +89,16 @@ photos_tool_class_init (PhotosToolClass *class)
   class->left_unclick_event = photos_tool_default_left_unclick_event;
   class->motion_event = photos_tool_default_motion_event;
 
+  signals[ACTIVATED] = g_signal_new ("activated",
+                                     G_TYPE_FROM_CLASS (class),
+                                     G_SIGNAL_RUN_LAST,
+                                     G_STRUCT_OFFSET (PhotosToolClass, activated),
+                                     NULL, /* accumulator */
+                                     NULL, /* accu_data */
+                                     g_cclosure_marshal_VOID__VOID,
+                                     G_TYPE_NONE,
+                                     0);
+
   signals[HIDE_REQUESTED] = g_signal_new ("hide-requested",
                                           G_TYPE_FROM_CLASS (class),
                                           G_SIGNAL_RUN_LAST,
diff --git a/src/photos-tool.h b/src/photos-tool.h
index a766555..5643719 100644
--- a/src/photos-tool.h
+++ b/src/photos-tool.h
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2015 Red Hat, Inc.
+ * Copyright © 2015, 2016 Red Hat, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -79,6 +79,7 @@ struct _PhotosToolClass
   gboolean      (*motion_event)               (PhotosTool *self, GdkEventMotion *event);
 
   /* signals */
+  void          (*activated)                  (PhotosTool *self);
   void          (*hide_requested)             (PhotosTool *self);
 };