App list: Added contents view custom animation framework.

ui/app_list/views/contents_view.cc

Index: ui/app_list/views/contents_view.cc
diff --git a/ui/app_list/views/contents_view.cc b/ui/app_list/views/contents_view.cc
index c9ea27655c55962d62d45ed9a73f2db58491bcb9..424c003002a3be0874ce32571e361151ea6da4ee 100644
--- a/ui/app_list/views/contents_view.cc
+++ b/ui/app_list/views/contents_view.cc
@@ -15,12 +15,12 @@
 #include "ui/app_list/views/app_list_main_view.h"
 #include "ui/app_list/views/apps_container_view.h"
 #include "ui/app_list/views/apps_grid_view.h"
+#include "ui/app_list/views/contents_animator.h"
 #include "ui/app_list/views/contents_switcher_view.h"
 #include "ui/app_list/views/search_box_view.h"
 #include "ui/app_list/views/search_result_list_view.h"
 #include "ui/app_list/views/start_page_view.h"
 #include "ui/events/event.h"
-#include "ui/gfx/animation/tween.h"
 #include "ui/resources/grit/ui_resources.h"
 #include "ui/views/view_model.h"
 #include "ui/views/view_model_utils.h"
@@ -82,7 +82,14 @@ void ContentsView::Init(AppListModel* model,
 
   page_before_search_ = initial_page_index;
   pagination_model_.SelectPage(initial_page_index, false);
+
   ActivePageChanged(false);
+
+  // Populate the contents animators.
+  AddAnimator(GetPageIndexForState(AppListModel::STATE_START),
+              GetPageIndexForState(AppListModel::STATE_APPS),
+              new StartToAppsAnimator(this));
+  default_animator_.reset(new DefaultAnimator(this));
 }
 
 void ContentsView::CancelDrag() {
@@ -199,18 +206,6 @@ bool ContentsView::IsShowingSearchResults() const {
              : IsStateActive(AppListModel::STATE_SEARCH_RESULTS);
 }
 
-gfx::Rect ContentsView::GetOffscreenPageBounds(int page_index) const {
-  gfx::Rect bounds(GetContentsBounds());
-  // The start page and search page origins are above; all other pages' origins
-  // are below.
-  int page_height = bounds.height();
-  bool origin_above =
-      GetPageIndexForState(AppListModel::STATE_START) == page_index ||
-      GetPageIndexForState(AppListModel::STATE_SEARCH_RESULTS) == page_index;
-  bounds.set_y(origin_above ? -page_height : page_height);
-  return bounds;
-}
-
 void ContentsView::UpdatePageBounds() {
   // The bounds calculations will potentially be mid-transition (depending on
   // the state of the PaginationModel).
@@ -226,24 +221,46 @@ void ContentsView::UpdatePageBounds() {
     }
   }
 
-  // Move |current_page| from 0 to its origin. Move |target_page| from its
-  // origin to 0.
-  gfx::Rect on_screen(GetDefaultContentsBounds());
-  gfx::Rect current_page_origin(GetOffscreenPageBounds(current_page));
-  gfx::Rect target_page_origin(GetOffscreenPageBounds(target_page));
-  gfx::Rect current_page_rect(
-      gfx::Tween::RectValueBetween(progress, on_screen, current_page_origin));
-  gfx::Rect target_page_rect(
-      gfx::Tween::RectValueBetween(progress, target_page_origin, on_screen));
+  bool reverse;
+  ContentsAnimator* animator =
+      GetAnimatorForTransition(current_page, target_page, &reverse);
 
-  view_model_->view_at(current_page)->SetBoundsRect(current_page_rect);
-  view_model_->view_at(target_page)->SetBoundsRect(target_page_rect);
+  if (reverse)

[calamity, 2014/11/05 06:29:07]

Mention that easing is handled by pagination_model.

[Matt Giuca, 2014/11/06 00:32:59]

Done.

+    animator->Update(1 - progress, target_page, current_page);
+  else
+    animator->Update(progress, current_page, target_page);
 }
 
 PaginationModel* ContentsView::GetAppsPaginationModel() {
   return apps_container_view_->apps_grid_view()->pagination_model();
 }
 
+void ContentsView::AddAnimator(int from_page,
+                               int to_page,
+                               ContentsAnimator* animator) {
+  contents_animators_.insert(
+      std::make_pair(std::make_pair(from_page, to_page),
+                     linked_ptr<ContentsAnimator>(animator)));
+}
+
+ContentsAnimator* ContentsView::GetAnimatorForTransition(int from_page,
+                                                         int to_page,
+                                                         bool* reverse) const {

[calamity, 2014/11/05 06:29:07]

Having this out var locks us into symmetrical animations. Using a
ReverseAnimation decorator on insertion would be more flexible if we need to
define non-symmetrical animations later. I don't really mind either way.

[Matt Giuca, 2014/11/06 00:32:59]

As discussed, I think this is a good idea if we need it. It's pretty easy to
change later (doesn't require changing the ContentsAnimator interface).

[calamity, 2014/11/06 05:34:47]

Acknowledged.

+  auto it = contents_animators_.find(std::make_pair(from_page, to_page));
+  if (it != contents_animators_.end()) {
+    *reverse = false;
+    return it->second.get();
+  }
+
+  it = contents_animators_.find(std::make_pair(to_page, from_page));
+  if (it != contents_animators_.end()) {
+    *reverse = true;
+    return it->second.get();
+  }
+
+  return default_animator_.get();
+}
+
 void ContentsView::ShowFolderContent(AppListFolderItem* item) {
   apps_container_view_->ShowActiveFolder(item);
 }