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 100 matching lines @@
 
   SetActivePageInternal(page_index, false);
 }
 
 int ContentsView::GetActivePageIndex() const {
   // The active page is changed at the beginning of an animation, not the end.
   return pagination_model_.SelectedTargetPage();
 }
 
 bool ContentsView::IsNamedPageActive(NamedPage named_page) const {
+  return IndexIsNamedPage(GetActivePageIndex(), named_page);
+}
+
+bool ContentsView::IndexIsNamedPage(int page_index,
+                                    NamedPage named_page) const {
+  // Find the index of the view corresponding to the given named_page.
   std::map<NamedPage, int>::const_iterator it =
       named_page_to_view_.find(named_page);
   if (it == named_page_to_view_.end())
     return false;
-  return it->second == GetActivePageIndex();
+  return it->second == page_index;
 }
 
 int ContentsView::GetPageIndexForNamedPage(NamedPage named_page) const {
   // Find the index of the view corresponding to the given named_page.
   std::map<NamedPage, int>::const_iterator it =
       named_page_to_view_.find(named_page);
   // GetPageIndexForNamedPage should never be called on a named_page that does
   // not have a corresponding view.
   DCHECK(it != named_page_to_view_.end());
   return it->second;
@@ skipping 41 matching lines @@
   SetActivePageInternal(show ? search_page : page_before_search_, show);
 }
 
 bool ContentsView::IsShowingSearchResults() const {
   return app_list::switches::IsExperimentalAppListEnabled()
              ? IsNamedPageActive(NAMED_PAGE_START) &&
                    start_page_view_->IsShowingSearchResults()
              : IsNamedPageActive(NAMED_PAGE_SEARCH_RESULTS);
 }
 
+int ContentsView::PageOrigin(const gfx::Rect& bounds, int page_index) const {

[calamity, 2014/09/10 01:56:40]

This is cleaner without |bounds| and I don't think calling GetContentsBounds()
here every time will have a noticeable performance impact.

[Matt Giuca, 2014/09/10 03:15:30]

Done.

+  // The start page and search page origins are above; all other pages' origins
+  // are below.
+  int page_height = bounds.height();
+  bool origin_above = IndexIsNamedPage(page_index, NAMED_PAGE_START) ||
+                      IndexIsNamedPage(page_index, NAMED_PAGE_SEARCH_RESULTS);
+  return origin_above ? -page_height : page_height;
+}
+
 void ContentsView::UpdatePageBounds() {
   gfx::Rect rect(GetContentsBounds());
   if (rect.IsEmpty())
     return;
 
   // The bounds calculations will potentially be mid-transition (depending on
   // the state of the PaginationModel).
   int current_page = std::max(0, pagination_model_.selected_page());
   int target_page = current_page;
   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;
+  // 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);
+  int current_page_origin = PageOrigin(rect, current_page);
+  int target_page_origin = PageOrigin(rect, target_page);
+  current_page_rect.set_y(progress * current_page_origin);
+  target_page_rect.set_y((1 - progress) * target_page_origin);
 
-  // Pages transition vertically.
-  int page_height = rect.height();
-  int transition_offset = progress * page_height * dir;
-
-  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);
 }
 
 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