[gnome-photos] tool-crop: Animate updates to the crop rectangle due to preset changes

[Debarshi Ray <debarshir src gnome org>]

commit afa055259eb5c3c88b67745ea7397b1a205376d3
Author: Umang Jain <mailumangjain gmail com>
Date:   Wed Jan 10 19:58:37 2018 +0100

    tool-crop: Animate updates to the crop rectangle due to preset changes
    
    This is done by animating between the currently visible size and
    position of the crop rectangle and its new values. Since these
    intermediate states are not meant to be used for image processing or
    otherwise exposed outside the tool, a small helper type called
    PhotosToolCropHelper is used instead. The properties of this helper are
    driven with EggAnimation, and the resulting "notify" emissions are used
    by the tool for rendering.
    
    Some changes by Debarshi Ray.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=791274

 src/photos-tool-crop.c | 166 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 151 insertions(+), 15 deletions(-)
---
diff --git a/src/photos-tool-crop.c b/src/photos-tool-crop.c
index 9e8a4d96..5fc05290 100644
--- a/src/photos-tool-crop.c
+++ b/src/photos-tool-crop.c
@@ -35,10 +35,12 @@
 #include <glib/gi18n.h>
 #include <gtk/gtk.h>
 
+#include "egg-animation.h"
 #include "photos-icons.h"
 #include "photos-image-view.h"
 #include "photos-tool.h"
 #include "photos-tool-crop.h"
+#include "photos-tool-crop-helper.h"
 #include "photos-utils.h"
 
 
@@ -78,6 +80,7 @@ struct _PhotosToolCropConstraint
 struct _PhotosToolCrop
 {
   PhotosTool parent_instance;
+  EggAnimation *constraint_animation;
   GAction *crop;
   GCancellable *cancellable;
   GeglRectangle bbox_zoomed;
@@ -99,9 +102,13 @@ struct _PhotosToolCrop
   gboolean reset;
   gdouble crop_aspect_ratio;
   gdouble crop_height;
+  gdouble crop_height_visible;
   gdouble crop_width;
+  gdouble crop_width_visible;
   gdouble crop_x;
+  gdouble crop_x_visible;
   gdouble crop_y;
+  gdouble crop_y_visible;
   gdouble event_x_last;
   gdouble event_y_last;
   gint list_box_active;
@@ -117,6 +124,12 @@ G_DEFINE_TYPE_WITH_CODE (PhotosToolCrop, photos_tool_crop, PHOTOS_TYPE_TOOL,
                                                          100));
 
 
+enum
+{
+  CONSTRAINT_ANIMATION_DURATION = 250 /* ms */
+};
+
+static const EggAnimationMode CONSTRAINT_ANIMATION_MODE = EGG_ANIMATION_EASE_OUT_CUBIC;
 static const gdouble CROP_MIN_SIZE = 16.0;
 static const gdouble HANDLE_OFFSET = 3.0;
 static const gdouble HANDLE_RADIUS = 8.0;
@@ -238,13 +251,13 @@ photos_tool_crop_redraw_damaged_area (PhotosToolCrop *self)
   gdouble y;
 
   x = photos_image_view_get_x (PHOTOS_IMAGE_VIEW (self->view));
-  x = -x + self->crop_x - damage_offset;
+  x = -x + self->crop_x_visible - damage_offset;
 
   y = photos_image_view_get_y (PHOTOS_IMAGE_VIEW (self->view));
-  y = -y + self->crop_y - damage_offset;
+  y = -y + self->crop_y_visible - damage_offset;
 
-  area.height = (gint) (self->crop_height + 2 * damage_offset + 0.5) + 2;
-  area.width = (gint) (self->crop_width + 2 * damage_offset + 0.5) + 2;
+  area.height = (gint) (self->crop_height_visible + 2 * damage_offset + 0.5) + 2;
+  area.width = (gint) (self->crop_width_visible + 2 * damage_offset + 0.5) + 2;
   area.x = (gint) (x + 0.5) - 1;
   area.y = (gint) (y + 0.5) - 1;
 
@@ -280,23 +293,31 @@ photos_tool_crop_surface_draw (PhotosToolCrop *self)
   cairo_paint (cr);
 
   cairo_set_source_rgba (cr, 0.0, 0.0, 0.0, 0.0);
-  cairo_rectangle (cr, self->crop_x, self->crop_y, self->crop_width, self->crop_height);
+  cairo_rectangle (cr,
+                   self->crop_x_visible,
+                   self->crop_y_visible,
+                   self->crop_width_visible,
+                   self->crop_height_visible);
   cairo_fill (cr);
 
   cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
 
   cairo_set_source_rgba (cr, 0.25, 0.507, 0.828, 1.0);
   photos_utils_draw_rectangle_handles (cr,
-                                       self->crop_x,
-                                       self->crop_y,
-                                       self->crop_width,
-                                       self->crop_height,
+                                       self->crop_x_visible,
+                                       self->crop_y_visible,
+                                       self->crop_width_visible,
+                                       self->crop_height_visible,
                                        HANDLE_OFFSET,
                                        HANDLE_RADIUS);
 
   cairo_set_source_rgba (cr, 0.8, 0.8, 0.8, 1.0);
   cairo_set_line_width (cr, 0.5);
-  photos_utils_draw_rectangle_thirds (cr, self->crop_x, self->crop_y, self->crop_width, self->crop_height);
+  photos_utils_draw_rectangle_thirds (cr,
+                                      self->crop_x_visible,
+                                      self->crop_y_visible,
+                                      self->crop_width_visible,
+                                      self->crop_height_visible);
 
   cairo_destroy (cr);
 }
@@ -348,6 +369,11 @@ photos_tool_crop_init_crop (PhotosToolCrop *self)
   self->crop_x = ((gdouble) self->bbox_zoomed.width - self->crop_width) / 2.0;
   self->crop_y = ((gdouble) self->bbox_zoomed.height - self->crop_height) / 2.0;
 
+  self->crop_height_visible = self->crop_height;
+  self->crop_width_visible = self->crop_width;
+  self->crop_x_visible = self->crop_x;
+  self->crop_y_visible = self->crop_y;
+
  out:
   photos_tool_crop_surface_draw (self);
 }
@@ -682,6 +708,14 @@ photos_tool_crop_set_crop (PhotosToolCrop *self, gdouble event_x, gdouble event_
  out:
   if (changed)
     {
+      if (self->constraint_animation != NULL)
+        egg_animation_stop (self->constraint_animation);
+
+      self->crop_height_visible = self->crop_height;
+      self->crop_width_visible = self->crop_width;
+      self->crop_x_visible = self->crop_x;
+      self->crop_y_visible = self->crop_y;
+
       photos_tool_crop_surface_draw (self);
       photos_tool_crop_redraw_damaged_area (self);
     }
@@ -842,12 +876,7 @@ photos_tool_crop_active_changed (PhotosToolCrop *self)
   if (self->crop_aspect_ratio < 0.0)
     return;
 
-  photos_tool_crop_redraw_damaged_area (self);
-
   photos_tool_crop_update_crop_after_constraint_changed (self);
-
-  photos_tool_crop_surface_draw (self);
-  photos_tool_crop_redraw_damaged_area (self);
 }
 
 
@@ -867,13 +896,78 @@ photos_tool_crop_list_box_update (PhotosToolCrop *self, GtkListBoxRow *active_ro
 }
 
 
+static void
+photos_tool_crop_notify_crop (GObject *object, GParamSpec *pspec, gpointer user_data)
+{
+  PhotosToolCrop *self = PHOTOS_TOOL_CROP (user_data);
+  PhotosToolCropHelper *helper = PHOTOS_TOOL_CROP_HELPER (object);
+
+  photos_tool_crop_redraw_damaged_area (self);
+
+  self->crop_height_visible = photos_tool_crop_helper_get_height (helper);
+  self->crop_width_visible = photos_tool_crop_helper_get_width (helper);
+  self->crop_x_visible = photos_tool_crop_helper_get_x (helper);
+  self->crop_y_visible = photos_tool_crop_helper_get_y (helper);
+
+  photos_tool_crop_surface_draw (self);
+  photos_tool_crop_redraw_damaged_area (self);
+}
+
+
+static void
+photos_tool_crop_start_constraint_animation (PhotosToolCrop *self)
+{
+  GdkFrameClock *frame_clock;
+  PhotosToolCropHelper *helper;
+
+  g_return_if_fail (self->constraint_animation == NULL);
+  g_return_if_fail (self->crop_height >= 0.0);
+  g_return_if_fail (self->crop_height_visible >= 0.0);
+  g_return_if_fail (self->crop_width >= 0.0);
+  g_return_if_fail (self->crop_width_visible >= 0.0);
+  g_return_if_fail (self->crop_x >= 0.0);
+  g_return_if_fail (self->crop_x_visible >= 0.0);
+  g_return_if_fail (self->crop_y >= 0.0);
+  g_return_if_fail (self->crop_y_visible >= 0.0);
+
+  helper = photos_tool_crop_helper_new ();
+  photos_tool_crop_helper_set_height (helper, self->crop_height_visible);
+  photos_tool_crop_helper_set_width (helper, self->crop_width_visible);
+  photos_tool_crop_helper_set_x (helper, self->crop_x_visible);
+  photos_tool_crop_helper_set_y (helper, self->crop_y_visible);
+  g_signal_connect (helper, "notify", G_CALLBACK (photos_tool_crop_notify_crop), self);
+
+  frame_clock = gtk_widget_get_frame_clock (GTK_WIDGET (self->view));
+
+  self->constraint_animation = egg_object_animate_full (g_object_ref (helper),
+                                                        CONSTRAINT_ANIMATION_MODE,
+                                                        CONSTRAINT_ANIMATION_DURATION,
+                                                        frame_clock,
+                                                        g_object_unref,
+                                                        helper,
+                                                        "height", self->crop_height,
+                                                        "width", self->crop_width,
+                                                        "x", self->crop_x,
+                                                        "y", self->crop_y,
+                                                        NULL);
+  g_object_add_weak_pointer (G_OBJECT (self->constraint_animation), (gpointer *) 
&self->constraint_animation);
+
+  g_object_unref (helper);
+}
+
+
 static void
 photos_tool_crop_list_box_row_activated (PhotosToolCrop *self, GtkListBoxRow *row)
 {
   photos_tool_crop_list_box_update (self, row);
 
   self->list_box_active = gtk_list_box_row_get_index (GTK_LIST_BOX_ROW (row));
+
+  if (self->constraint_animation != NULL)
+    egg_animation_stop (self->constraint_animation);
+
   photos_tool_crop_active_changed (self);
+  photos_tool_crop_start_constraint_animation (self);
 }
 
 
@@ -883,7 +977,11 @@ photos_tool_crop_landscape_button_toggled (PhotosToolCrop *self)
   if (!gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (self->landscape_button)))
     goto out;
 
+  if (self->constraint_animation != NULL)
+    egg_animation_stop (self->constraint_animation);
+
   photos_tool_crop_active_changed (self);
+  photos_tool_crop_start_constraint_animation (self);
 
  out:
   return;
@@ -896,7 +994,11 @@ photos_tool_crop_portrait_button_toggled (PhotosToolCrop *self)
   if (!gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (self->portrait_button)))
     goto out;
 
+  if (self->constraint_animation != NULL)
+    egg_animation_stop (self->constraint_animation);
+
   photos_tool_crop_active_changed (self);
+  photos_tool_crop_start_constraint_animation (self);
 
  out:
   return;
@@ -978,12 +1080,21 @@ photos_tool_crop_size_allocate (PhotosToolCrop *self, GdkRectangle *allocation)
   GeglRectangle bbox_zoomed_old = self->bbox_zoomed;
   gdouble zoom;
 
+  if (self->constraint_animation != NULL)
+    egg_animation_stop (self->constraint_animation);
+
   zoom = photos_image_view_get_zoom (PHOTOS_IMAGE_VIEW (self->view));
   self->bbox_zoomed.height = (gint) (zoom * self->bbox_source.height + 0.5);
   self->bbox_zoomed.width = (gint) (zoom * self->bbox_source.width + 0.5);
 
   photos_tool_crop_surface_create (self);
+
   photos_tool_crop_update_crop_after_size_allocate (self, &self->bbox_zoomed, &bbox_zoomed_old);
+  self->crop_height_visible = self->crop_height;
+  self->crop_width_visible = self->crop_width;
+  self->crop_x_visible = self->crop_x;
+  self->crop_y_visible = self->crop_y;
+
   photos_tool_crop_surface_draw (self);
 }
 
@@ -1016,11 +1127,19 @@ photos_tool_crop_process (GObject *source_object, GAsyncResult *res, gpointer us
   photos_tool_crop_surface_create (self);
 
   self->crop_height *= zoom;
+  self->crop_height_visible = self->crop_height;
+
   self->crop_width *= zoom;
+  self->crop_width_visible = self->crop_width;
+
   self->crop_x *= zoom;
+  self->crop_x_visible = self->crop_x;
+
   self->crop_y *= zoom;
+  self->crop_y_visible = self->crop_y;
 
   self->crop_aspect_ratio = self->crop_width / self->crop_height;
+
   active = photos_tool_crop_find_constraint (self, self->crop_aspect_ratio);
   orientation_button = self->crop_aspect_ratio > 1.0 ? self->landscape_button : self->portrait_button;
   photos_tool_crop_set_active (self, (gint) active, GTK_TOGGLE_BUTTON (orientation_button));
@@ -1096,10 +1215,18 @@ photos_tool_crop_activate (PhotosTool *tool, PhotosBaseItem *item, PhotosImageVi
        * view's zoom, which we won't know until we have finished
        * processing with the reset gegl:crop values.
        */
+
       self->crop_height = height;
+      self->crop_height_visible = self->crop_height;
+
       self->crop_width = width;
+      self->crop_width_visible = self->crop_width;
+
       self->crop_x = x;
+      self->crop_x_visible = self->crop_x;
+
       self->crop_y = y;
+      self->crop_y_visible = self->crop_y;
 
       photos_base_item_operation_remove_async (item,
                                                "gegl:crop",
@@ -1145,6 +1272,9 @@ photos_tool_crop_deactivate (PhotosTool *tool)
 
   g_return_if_fail (self->activated);
 
+  if (self->constraint_animation != NULL)
+    egg_animation_stop (self->constraint_animation);
+
   if (!self->reset)
     {
       GVariantBuilder parameter;
@@ -1293,6 +1423,12 @@ photos_tool_crop_dispose (GObject *object)
 {
   PhotosToolCrop *self = PHOTOS_TOOL_CROP (object);
 
+  if (self->constraint_animation != NULL)
+    {
+      egg_animation_stop (self->constraint_animation);
+      g_assert_null (self->constraint_animation);
+    }
+
   if (self->cancellable != NULL)
     {
       g_cancellable_cancel (self->cancellable);