react-native/ReactCommon/fabric/view/ViewEventEmitter.h

131 lines
3.1 KiB
C++

/**
* Copyright (c) 2015-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <memory>
#include <fabric/core/EventEmitter.h>
#include <fabric/core/LayoutMetrics.h>
#include <fabric/core/ReactPrimitives.h>
namespace facebook {
namespace react {
/*
* Describes an individual touch point for a touch event.
* See https://www.w3.org/TR/touch-events/ for more details.
*/
struct Touch {
/*
* The coordinate of point relative to the root component in points.
*/
Point pagePoint;
/*
* The coordinate of point relative to the target component in points.
*/
Point offsetPoint;
/*
* The coordinate of point relative to the screen component in points.
*/
Point screenPoint;
/*
* An identification number for each touch point.
*/
int identifier;
/*
* The tag of a component on which the touch point started when it was first placed on the surface,
* even if the touch point has since moved outside the interactive area of that element.
*/
Tag target;
/*
* The force of the touch.
*/
Float force;
/*
* The time in seconds when the touch occurred or when it was last mutated.
*/
Float timestamp;
/*
* The particular implementation of `Hasher` and (especially) `Comparator`
* make sense only when `Touch` object is used as a *key* in indexed collections.
* Because of that they are expressed as separate classes.
*/
struct Hasher {
size_t operator()(const Touch &touch) const {
return std::hash<decltype(touch.identifier)>()(touch.identifier);
}
};
struct Comparator {
bool operator()(const Touch &lhs, const Touch &rhs) const {
return lhs.identifier == rhs.identifier;
}
};
};
using Touches = std::unordered_set<Touch, Touch::Hasher, Touch::Comparator>;
/*
* Defines the `touchstart`, `touchend`, `touchmove`, and `touchcancel` event types.
*/
struct TouchEvent {
/*
* A list of Touches for every point of contact currently touching the surface.
*/
Touches touches;
/*
* A list of Touches for every point of contact which contributed to the event.
*/
Touches changedTouches;
/*
* A list of Touches for every point of contact that is touching the surface
* and started on the element that is the target of the current event.
*/
Touches targetTouches;
};
class ViewEventEmitter;
using SharedViewEventEmitter = std::shared_ptr<const ViewEventEmitter>;
class ViewEventEmitter:
public EventEmitter {
public:
using EventEmitter::EventEmitter;
#pragma mark - Accessibility
void onAccessibilityAction(const std::string &name) const;
void onAccessibilityTap() const;
void onAccessibilityMagicTap() const;
#pragma mark - Layout
void onLayout(const LayoutMetrics &layoutMetrics) const;
#pragma mark - Touches
void onTouchStart(const TouchEvent &event) const;
void onTouchMove(const TouchEvent &event) const;
void onTouchEnd(const TouchEvent &event) const;
void onTouchCancel(const TouchEvent &event) const;
};
} // namespace react
} // namespace facebook