[gnome-photos/wip/rishi/gesture-zoom: 9/10] Add zoom-begin/end

[Debarshi Ray <debarshir src gnome org>]

commit d6d37ce2d667ae62183dedbdec36e3d471536ce6
Author: Debarshi Ray <debarshir gnome org>
Date:   Sat Oct 14 08:59:31 2017 +0200

    Add zoom-begin/end

 src/photos-application.c  |   12 +++++++
 src/photos-preview-view.c |   78 +++++++++++++++++++++++++++++++++++++++++++-
 src/photos-utils.h        |    3 +-
 3 files changed, 90 insertions(+), 3 deletions(-)
---
diff --git a/src/photos-application.c b/src/photos-application.c
index 4957d98..4fe57c6 100644
--- a/src/photos-application.c
+++ b/src/photos-application.c
@@ -111,7 +111,9 @@ struct _PhotosApplication
   GSimpleAction *set_ss_action;
   GSimpleAction *share_action;
   GSimpleAction *sharpen_action;
+  GSimpleAction *zoom_begin_action;
   GSimpleAction *zoom_best_fit_action;
+  GSimpleAction *zoom_end_action;
   GSimpleAction *zoom_in_action;
   GSimpleAction *zoom_out_action;
   GtkWidget *main_window;
@@ -375,6 +377,7 @@ photos_application_actions_update (PhotosApplication *self)
   selection_mode = photos_utils_get_selection_mode ();
 
   g_simple_action_set_enabled (self->zoom_best_fit_action, FALSE);
+  g_simple_action_set_enabled (self->zoom_end_action, FALSE);
   g_simple_action_set_enabled (self->zoom_out_action, FALSE);
 
   enable = (mode == PHOTOS_WINDOW_MODE_EDIT);
@@ -419,6 +422,7 @@ photos_application_actions_update (PhotosApplication *self)
   g_simple_action_set_enabled (self->gear_action, enable);
   g_simple_action_set_enabled (self->set_bg_action, enable);
   g_simple_action_set_enabled (self->set_ss_action, enable);
+  g_simple_action_set_enabled (self->zoom_begin_action, enable);
   g_simple_action_set_enabled (self->zoom_in_action, enable);
 
   enable = ((load_state == PHOTOS_LOAD_STATE_FINISHED && mode == PHOTOS_WINDOW_MODE_PREVIEW)
@@ -2060,9 +2064,15 @@ photos_application_startup (GApplication *application)
   self->sharpen_action = g_simple_action_new ("sharpen-current", G_VARIANT_TYPE_DOUBLE);
   g_action_map_add_action (G_ACTION_MAP (self), G_ACTION (self->sharpen_action));
 
+  self->zoom_begin_action = g_simple_action_new ("zoom-begin", G_VARIANT_TYPE_VARDICT);
+  g_action_map_add_action (G_ACTION_MAP (self), G_ACTION (self->zoom_begin_action));
+
   self->zoom_best_fit_action = g_simple_action_new ("zoom-best-fit", NULL);
   g_action_map_add_action (G_ACTION_MAP (self), G_ACTION (self->zoom_best_fit_action));
 
+  self->zoom_end_action = g_simple_action_new ("zoom-end", G_VARIANT_TYPE_VARDICT);
+  g_action_map_add_action (G_ACTION_MAP (self), G_ACTION (self->zoom_end_action));
+
   self->zoom_in_action = g_simple_action_new ("zoom-in", G_VARIANT_TYPE_VARDICT);
   g_action_map_add_action (G_ACTION_MAP (self), G_ACTION (self->zoom_in_action));
 
@@ -2182,7 +2192,9 @@ photos_application_dispose (GObject *object)
   g_clear_object (&self->set_ss_action);
   g_clear_object (&self->share_action);
   g_clear_object (&self->sharpen_action);
+  g_clear_object (&self->zoom_begin_action);
   g_clear_object (&self->zoom_best_fit_action);
+  g_clear_object (&self->zoom_end_action);
   g_clear_object (&self->zoom_in_action);
   g_clear_object (&self->zoom_out_action);
   g_clear_object (&self->shr_pnt_mngr);
diff --git a/src/photos-preview-view.c b/src/photos-preview-view.c
index e409334..0bcb19b 100644
--- a/src/photos-preview-view.c
+++ b/src/photos-preview-view.c
@@ -47,7 +47,9 @@
 struct _PhotosPreviewView
 {
   GtkBin parent_instance;
+  GAction *zoom_begin_action;
   GAction *zoom_best_fit_action;
+  GAction *zoom_end_action;
   GAction *zoom_in_action;
   GAction *zoom_out_action;
   GCancellable *cancellable;
@@ -63,6 +65,7 @@ struct _PhotosPreviewView
   gboolean grabbed;
   gdouble event_x_last;
   gdouble event_y_last;
+  gdouble zoom_begin;
   gdouble zoom_best_fit;
 };
 
@@ -836,6 +839,26 @@ photos_preview_view_window_mode_changed (PhotosPreviewView *self, PhotosWindowMo
 
 
 static void
+photos_preview_view_zoom_begin (PhotosPreviewView *self, GVariant *parameter)
+{
+  GtkWidget *view;
+  GtkWidget *view_container;
+  PhotosZoomEvent event;
+
+  event = photos_utils_get_zoom_event (parameter);
+  g_return_if_fail (event == PHOTOS_ZOOM_EVENT_TOUCH);
+
+  view_container = gtk_stack_get_visible_child (GTK_STACK (self->stack));
+  view = photos_preview_view_get_view_from_view_container (view_container);
+  self->zoom_begin = photos_image_view_get_zoom (PHOTOS_IMAGE_VIEW (view));
+  g_simple_action_set_enabled (G_SIMPLE_ACTION (self->zoom_begin_action), FALSE);
+  g_simple_action_set_enabled (G_SIMPLE_ACTION (self->zoom_end_action), TRUE);
+  photos_preview_nav_buttons_set_auto_hide (self->nav_buttons, FALSE);
+  photos_preview_nav_buttons_set_show_navigation (self->nav_buttons, FALSE);
+}
+
+
+static void
 photos_preview_view_zoom_best_fit (PhotosPreviewView *self)
 {
   GtkWidget *view;
@@ -851,6 +874,22 @@ photos_preview_view_zoom_best_fit (PhotosPreviewView *self)
 }
 
 
+static void
+photos_preview_view_zoom_end (PhotosPreviewView *self, GVariant *parameter)
+{
+  PhotosZoomEvent event;
+
+  event = photos_utils_get_zoom_event (parameter);
+  g_return_if_fail (event == PHOTOS_ZOOM_EVENT_TOUCH);
+
+  self->zoom_begin = 0.0;
+  g_simple_action_set_enabled (G_SIMPLE_ACTION (self->zoom_begin_action), TRUE);
+  g_simple_action_set_enabled (G_SIMPLE_ACTION (self->zoom_end_action), FALSE);
+  photos_preview_nav_buttons_set_auto_hide (self->nav_buttons, TRUE);
+  photos_preview_nav_buttons_set_show_navigation (self->nav_buttons, TRUE);
+}
+
+
 static gdouble
 photos_preview_view_calculate_zoom_for_non_touch (PhotosPreviewView *self,
                                                   gdouble delta,
@@ -865,6 +904,7 @@ photos_preview_view_calculate_zoom_for_non_touch (PhotosPreviewView *self,
   gdouble zoom_factor_for_delta;
 
   g_return_val_if_fail (event != PHOTOS_ZOOM_EVENT_NONE, 0.0);
+  g_return_val_if_fail (event != PHOTOS_ZOOM_EVENT_TOUCH, 0.0);
   g_return_val_if_fail ((event == PHOTOS_ZOOM_EVENT_KEYBOARD_ACCELERATOR && photos_utils_equal_double 
(delta, 1.0))
                         || (event == PHOTOS_ZOOM_EVENT_MOUSE_CLICK && photos_utils_equal_double (delta, 1.0))
                         || (event == PHOTOS_ZOOM_EVENT_SCROLL && delta >= 0.0),
@@ -887,6 +927,7 @@ photos_preview_view_calculate_zoom_for_non_touch (PhotosPreviewView *self,
       break;
 
     case PHOTOS_ZOOM_EVENT_NONE:
+    case PHOTOS_ZOOM_EVENT_TOUCH:
     default:
       g_assert_not_reached ();
       break;
@@ -921,7 +962,8 @@ photos_preview_view_zoom_in (PhotosPreviewView *self, GVariant *parameter)
   delta = photos_utils_get_zoom_delta (parameter);
   g_return_if_fail ((event == PHOTOS_ZOOM_EVENT_KEYBOARD_ACCELERATOR && photos_utils_equal_double (delta, 
1.0))
                     || (event == PHOTOS_ZOOM_EVENT_MOUSE_CLICK && photos_utils_equal_double (delta, 1.0))
-                    || (event == PHOTOS_ZOOM_EVENT_SCROLL && delta >= 0.0));
+                    || (event == PHOTOS_ZOOM_EVENT_SCROLL && delta >= 0.0)
+                    || (event == PHOTOS_ZOOM_EVENT_TOUCH && delta >= 0.0));
 
   switch (event)
     {
@@ -931,12 +973,22 @@ photos_preview_view_zoom_in (PhotosPreviewView *self, GVariant *parameter)
       zoom = photos_preview_view_calculate_zoom_for_non_touch (self, delta, event, TRUE);
       break;
 
+    case PHOTOS_ZOOM_EVENT_TOUCH:
+      zoom = self->zoom_begin * delta;
+      break;
+
     case PHOTOS_ZOOM_EVENT_NONE:
     default:
       g_assert_not_reached ();
       break;
     }
 
+  if (zoom < self->zoom_best_fit || photos_utils_equal_double (self->zoom_best_fit, zoom))
+    {
+      g_return_if_fail (event == PHOTOS_ZOOM_EVENT_TOUCH);
+      goto out;
+    }
+
   view_container = gtk_stack_get_visible_child (GTK_STACK (self->stack));
   view = photos_preview_view_get_view_from_view_container (view_container);
   photos_image_view_set_zoom (PHOTOS_IMAGE_VIEW (view), zoom);
@@ -945,6 +997,9 @@ photos_preview_view_zoom_in (PhotosPreviewView *self, GVariant *parameter)
   g_simple_action_set_enabled (G_SIMPLE_ACTION (self->zoom_out_action), TRUE);
   photos_preview_nav_buttons_set_auto_hide (self->nav_buttons, FALSE);
   photos_preview_nav_buttons_set_show_navigation (self->nav_buttons, FALSE);
+
+ out:
+  return;
 }
 
 
@@ -965,7 +1020,8 @@ photos_preview_view_zoom_out (PhotosPreviewView *self, GVariant *parameter)
   delta = photos_utils_get_zoom_delta (parameter);
   g_return_if_fail ((event == PHOTOS_ZOOM_EVENT_KEYBOARD_ACCELERATOR && photos_utils_equal_double (delta, 
1.0))
                     || (event == PHOTOS_ZOOM_EVENT_MOUSE_CLICK && photos_utils_equal_double (delta, 1.0))
-                    || (event == PHOTOS_ZOOM_EVENT_SCROLL && delta >= 0.0));
+                    || (event == PHOTOS_ZOOM_EVENT_SCROLL && delta >= 0.0)
+                    || (event == PHOTOS_ZOOM_EVENT_TOUCH && delta >= 0.0));
 
   switch (event)
     {
@@ -975,6 +1031,10 @@ photos_preview_view_zoom_out (PhotosPreviewView *self, GVariant *parameter)
       zoom = photos_preview_view_calculate_zoom_for_non_touch (self, delta, event, FALSE);
       break;
 
+    case PHOTOS_ZOOM_EVENT_TOUCH:
+      zoom = self->zoom_begin * delta;
+      break;
+
     case PHOTOS_ZOOM_EVENT_NONE:
     default:
       g_assert_not_reached ();
@@ -1156,6 +1216,13 @@ photos_preview_view_init (PhotosPreviewView *self)
   action = g_action_map_lookup_action (G_ACTION_MAP (app), "sharpen-current");
   g_signal_connect_object (action, "activate", G_CALLBACK (photos_preview_view_sharpen), self, 
G_CONNECT_SWAPPED);
 
+  self->zoom_begin_action = g_action_map_lookup_action (G_ACTION_MAP (app), "zoom-begin");
+  g_signal_connect_object (self->zoom_begin_action,
+                           "activate",
+                           G_CALLBACK (photos_preview_view_zoom_begin),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   self->zoom_best_fit_action = g_action_map_lookup_action (G_ACTION_MAP (app), "zoom-best-fit");
   g_signal_connect_object (self->zoom_best_fit_action,
                            "activate",
@@ -1163,6 +1230,13 @@ photos_preview_view_init (PhotosPreviewView *self)
                            self,
                            G_CONNECT_SWAPPED);
 
+  self->zoom_end_action = g_action_map_lookup_action (G_ACTION_MAP (app), "zoom-end");
+  g_signal_connect_object (self->zoom_end_action,
+                           "activate",
+                           G_CALLBACK (photos_preview_view_zoom_end),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   self->zoom_in_action = g_action_map_lookup_action (G_ACTION_MAP (app), "zoom-in");
   g_signal_connect_object (self->zoom_in_action,
                            "activate",
diff --git a/src/photos-utils.h b/src/photos-utils.h
index e40ef2a..0956f58 100644
--- a/src/photos-utils.h
+++ b/src/photos-utils.h
@@ -57,7 +57,8 @@ typedef enum
   PHOTOS_ZOOM_EVENT_NONE,
   PHOTOS_ZOOM_EVENT_KEYBOARD_ACCELERATOR,
   PHOTOS_ZOOM_EVENT_MOUSE_CLICK,
-  PHOTOS_ZOOM_EVENT_SCROLL
+  PHOTOS_ZOOM_EVENT_SCROLL,
+  PHOTOS_ZOOM_EVENT_TOUCH
 } PhotosZoomEvent;
 
 GdkPixbuf       *photos_utils_center_pixbuf               (GdkPixbuf *pixbuf, gint size);