如何在iPhone，iPad和Android设备上计算TouchPoint的直径?

本文介绍了如何在iPhone，iPad和Android设备上计算TouchPoint的直径?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

现在我了解到，默认情况下，我们在iPhone中可以有5个接触点，并且可以在不同的SDK上启用各种接触点.但是我已经完成了接触点的注册并获得了距离，接触点的实际数量.我想知道是否有一种方法可以实现并获取特定接触点的直径，例如计算与食指相比的拇指触感，有什么想法吗?

Now i understand we can have 5 touch points by default in iPhone and have varied touch points enabled onto the different SDKs. However i have accomplished registering the touch points and getting distances, actual number of touch points. I would want to know if there's a way to accomplish and get the Diameter of a particular touch point for e.g. calculating the thumb touch in comparison with the index finger, Any ideas?

推荐答案

我认为Apple相当清楚地表明，他们不打算让第三方开发人员访问底层的多点触控信息.摘自Apple文档 iOS中的事件处理:

I think Apple makes it fairly clear that they don't intend to give third-party developers access to low-level multi-touch information. From Apple's documentation on Event Handling in iOS:

屏幕上的手指可以提供非常不同的精度 而不是鼠标指针.当用户触摸屏幕时， 接触实际上是椭圆形，并且趋向于在该点以下偏移 用户认为他或她触摸过的地方.这个联系补丁"也 根据手指触摸屏幕的大小和形状的不同而有所不同， 手指的大小，手指在屏幕上的压力， 手指的方向和其他因素.底层 Multi-Touch系统会为您分析所有这些信息，并且 计算单个接触点.

A finger on the screen affords a much different level of precision than a mouse pointer. When a user touches the screen, the area of contact is actually elliptical and tends to be offset below the point where the user thinks he or she touched. This "contact patch" also varies in size and shape based on which finger is touching the screen, the size of the finger, the pressure of the finger on the screen, the orientation of the finger, and other factors. The underlying Multi-Touch system analyzes all of this information for you and computes a single touch point.