| // Copyright 2019 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_DOM_INTERSECTION_OBSERVER_TARGET_H_ |
| #define COBALT_DOM_INTERSECTION_OBSERVER_TARGET_H_ |
| |
| #include "cobalt/dom/intersection_observer_registration_list.h" |
| #include "cobalt/math/rect_f.h" |
| |
| namespace cobalt { |
| namespace dom { |
| |
| class Element; |
| class HTMLElement; |
| |
| // The Intersection Observer spec describes a sequence of steps to update the |
| // the target elements of an observer in step 2.2 of the "Run the Update |
| // Intersection Observations Steps" algorithm. This helper class represents |
| // one of those target elements. |
| // https://www.w3.org/TR/intersection-observer/#update-intersection-observations-algo |
| class IntersectionObserverTarget { |
| public: |
| explicit IntersectionObserverTarget(Element* target_element); |
| |
| void RegisterIntersectionObserver( |
| const scoped_refptr<IntersectionObserver>& observer); |
| |
| void UnregisterIntersectionObserver( |
| const scoped_refptr<IntersectionObserver>& observer); |
| |
| void UpdateIntersectionObservationsForTarget( |
| const scoped_refptr<IntersectionObserver>& observer); |
| |
| private: |
| scoped_refptr<DOMRectReadOnly> GetRootBounds( |
| const scoped_refptr<HTMLElement>& html_intersection_root, |
| scoped_refptr<cssom::PropertyListValue> root_margin_property_value); |
| |
| int32 GetUsedLengthOfRootMarginPropertyValue( |
| const scoped_refptr<cssom::PropertyValue>& length_property_value, |
| float percentage_base); |
| |
| scoped_refptr<DOMRectReadOnly> ComputeIntersectionBetweenTargetAndRoot( |
| const scoped_refptr<HTMLElement>& intersection_root, |
| const scoped_refptr<DOMRectReadOnly>& root_bounds, |
| const scoped_refptr<DOMRectReadOnly>& target_rect, |
| const scoped_refptr<HTMLElement>& html_target); |
| |
| // Similar to the IntersectRects function in math::RectF, but handles edge |
| // adjacent intersections as valid intersections (instead of returning a |
| // rectangle with zero dimensions) |
| math::RectF IntersectIntersectionObserverRects(const math::RectF& a, |
| const math::RectF& b); |
| |
| Element* target_element_; |
| |
| IntersectionObserverRegistrationList intersection_observer_registration_list_; |
| }; |
| |
| } // namespace dom |
| } // namespace cobalt |
| |
| #endif // COBALT_DOM_INTERSECTION_OBSERVER_TARGET_H_ |