| // Copyright 2022 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_UI_NAVIGATION_SCROLL_ENGINE_SCROLL_ENGINE_H_ |
| #define COBALT_UI_NAVIGATION_SCROLL_ENGINE_SCROLL_ENGINE_H_ |
| |
| #include <map> |
| #include <queue> |
| #include <vector> |
| |
| #include "base/threading/thread.h" |
| #include "base/time/time.h" |
| #include "base/timer/timer.h" |
| #include "cobalt/base/token.h" |
| #include "cobalt/dom/pointer_event.h" |
| #include "cobalt/dom/pointer_event_init.h" |
| #include "cobalt/math/vector2d_f.h" |
| #include "cobalt/ui_navigation/nav_item.h" |
| |
| namespace cobalt { |
| namespace ui_navigation { |
| namespace scroll_engine { |
| |
| // kDragDistanceThreshold is measured in viewport coordinate distance. |
| const float kDragDistanceThreshold = 20.0f; |
| |
| typedef enum ScrollType { |
| Unknown, |
| Horizontal, |
| Vertical, |
| Free, |
| } ScrollType; |
| |
| class ScrollEngine { |
| public: |
| ScrollEngine(); |
| ~ScrollEngine(); |
| |
| void HandlePointerEvent(base::Token type, const dom::PointerEventInit& event); |
| void HandleScrollStart(scoped_refptr<ui_navigation::NavItem> scroll_container, |
| ScrollType scroll_type, int32_t pointer_id, |
| math::Vector2dF initial_coordinates, |
| uint64 initial_time_stamp, |
| math::Vector2dF current_coordinates, |
| uint64 current_time_stamp); |
| void CancelActiveScrollsForNavItems( |
| std::vector<scoped_refptr<ui_navigation::NavItem>> scrolls_to_cancel); |
| |
| void HandlePointerEventForActiveItem( |
| scoped_refptr<dom::PointerEvent> pointer_event); |
| void ScrollNavItemsWithDecayingScroll(); |
| void MaybeFreeScrollActiveNavItem(); |
| |
| base::Thread* thread() { return &scroll_engine_; } |
| |
| private: |
| base::Thread scroll_engine_{"ScrollEngineThread"}; |
| base::RepeatingTimer free_scroll_timer_; |
| |
| struct EventPositionWithTimeStamp { |
| EventPositionWithTimeStamp(math::Vector2dF position, uint64 time_stamp) |
| : position(position), time_stamp(time_stamp) {} |
| math::Vector2dF position; |
| uint64 time_stamp; |
| }; |
| |
| struct FreeScrollingNavItem { |
| FreeScrollingNavItem(scoped_refptr<NavItem> nav_item, |
| math::Vector2dF initial_offset, |
| math::Vector2dF target_offset) |
| : nav_item(nav_item), |
| initial_offset(initial_offset), |
| target_offset(target_offset), |
| last_change(base::Time::Now()) {} |
| scoped_refptr<NavItem> nav_item; |
| math::Vector2dF initial_offset; |
| math::Vector2dF target_offset; |
| base::Time last_change; |
| }; |
| |
| std::queue<EventPositionWithTimeStamp> previous_events_; |
| const scoped_refptr<cssom::TimingFunction>& timing_function_; |
| |
| scoped_refptr<NavItem> active_item_; |
| math::Vector2dF active_velocity_; |
| ScrollType active_scroll_type_ = ScrollType::Unknown; |
| std::map<uint32_t, scoped_refptr<dom::PointerEvent>> events_to_handle_; |
| std::vector<FreeScrollingNavItem> nav_items_with_decaying_scroll_; |
| }; |
| |
| |
| } // namespace scroll_engine |
| } // namespace ui_navigation |
| } // namespace cobalt |
| |
| #endif // COBALT_UI_NAVIGATION_SCROLL_ENGINE_SCROLL_ENGINE_H_ |