Experimental app list: Change transition animations of top-level pages.

ui/app_list/views/contents_view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/contents_view.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 185 matching lines @@
   double progress = 1;
   if (pagination_model_.has_transition()) {
     const PaginationModel::Transition& transition =
         pagination_model_.transition();
     if (pagination_model_.is_valid_page(transition.target_page)) {
       target_page = transition.target_page;
       progress = transition.progress;
     }
   }
 
-  gfx::Rect incoming_target(rect);
-  gfx::Rect outgoing_target(rect);
-  int dir = target_page > current_page ? -1 : 1;
+  // A page's origin is its off-screen resting place (top). The start page's
+  // origin is above; all other pages' origins are below.
+  int start_page = GetPageIndexForNamedPage(NAMED_PAGE_START);
+  int page_height = rect.height();
+  int current_page_origin =
+      current_page == start_page ? -page_height : page_height;
+  int target_page_origin =
+      target_page == start_page ? -page_height : page_height;
 
-  // Pages transition vertically.
-  int page_height = rect.height();
-  int transition_offset = progress * page_height * dir;
+  // Move |current_page| from 0 to its origin. Move |target_page| from its
+  // origin to 0.
+  gfx::Rect current_page_rect(rect);
+  gfx::Rect target_page_rect(rect);
+  current_page_rect.set_y(progress * current_page_origin);
+  target_page_rect.set_y((1 - progress) * target_page_origin);
 
-  outgoing_target.set_y(transition_offset);
-  incoming_target.set_y(dir < 0 ? transition_offset + page_height
-                                : transition_offset - page_height);
-
-  view_model_->view_at(current_page)->SetBoundsRect(outgoing_target);
-  view_model_->view_at(target_page)->SetBoundsRect(incoming_target);
+  view_model_->view_at(current_page)->SetBoundsRect(current_page_rect);
+  view_model_->view_at(target_page)->SetBoundsRect(target_page_rect);

[calamity, 2014/09/09 09:13:21]

I think you need to do an IsExperimentalAppListEnabled() somewhere.

[Matt Giuca, 2014/09/10 01:45:36]

Done.

Whoops.

 }
 
 PaginationModel* ContentsView::GetAppsPaginationModel() {
   return apps_container_view_->apps_grid_view()->pagination_model();
 }
 
 void ContentsView::ShowFolderContent(AppListFolderItem* item) {
   apps_container_view_->ShowActiveFolder(item);
 }
 
@@ skipping 70 matching lines @@
 }
 
 void ContentsView::TransitionStarted() {
 }
 
 void ContentsView::TransitionChanged() {
   UpdatePageBounds();
 }
 
 }  // namespace app_list