有什么办法可以告诉我屏幕有多难按下 [英] Is there any way at all that I can tell how hard the screen is being pressed

问题描述

我想找到触摸的压力。我只是不知道如何通过越狱和获取原始触摸数据来实现这一结果。有谁知道我会怎么做？

I want to find the pressure of the touch. I just don't know how to accomplish that result with out jailbreaking it and getting the raw touch data. Does anyone know How I would do this?

推荐答案

你无法从SDK 或获得压力无证方法。但是可以检测未记录方法的触摸大小。

You cannot get the pressure from the SDK nor undocumented methods. However you can detect the size of touch with undocumented methods.

在GSEvent中，是UIEvent的低级表示，有一种结构称为 GSPathInfo ：

In the GSEvent, which is a lower-level representation of UIEvent, there is a structure known as GSPathInfo with members:

typedef struct GSPathInfo {
    unsigned char pathIndex;        // 0x0 = 0x5C
    unsigned char pathIdentity;     // 0x1 = 0x5D
    unsigned char pathProximity;    // 0x2 = 0x5E
    CGFloat pathPressure;               // 0x4 = 0x60
    CGFloat pathMajorRadius;        // 0x8 = 0x64
    CGPoint pathLocation;           // 0xC = 0x68
    GSWindowRef pathWindow;         // 0x14 = 0x70
} GSPathInfo;

我们注意到 pathPressure 和 pathMajorRadius 。我可以向你保证压力成员没用 - 它总是给出0.然而 pathMajorRadius 确实包含有意义的信息 - 它给出了触摸的主要半径以毫米为单位。因此，如果是半径较重或轻触，您可以给出非常粗略的估计。

We notice that there is a pathPressure and pathMajorRadius. I can assure you the pressure member is useless – it always gives 0. However pathMajorRadius does contain meaningful information – it gives the major radius of the touch in millimeters. You can therefore give an extremely rough estimation if it's a heavy touch or light touch from the radius.

  -(void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
     GSEventRef gsevent = [event _gsEvent];
     GSPathInfo first_touch = GSEventGetPathInfoAtIndex(gsevent, 0);
     if (first_touch.pathMajorRadius >= 9)
        NSLog(@"huge (heavy) touch");
     else
        NSLog(@"little (light) touch");
  }

让我再次警告你这是无证件和你不应该在AppStore应用程序中使用它。

Let me warn you again this is undocumented and you should not use it in AppStore apps.

编辑：在3.2及以上的GSPathInfo的 pathMajorRadius 在UITouch中也可以作为未记录的属性使用：

On 3.2 and above the pathMajorRadius of a GSPathInfo is also available as an undocumented property in UITouch:

@property(assign, nonatomic, setter=_setPathMajorRadius:) CGFloat _pathMajorRadius;

所以上面的代码可以使用纯Objective-C重写：

so the code above could be rewritten using pure Objective-C:

  -(void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
     UITouch* any_touch = [touches anyObject];
     if (any_touch._pathMajorRadius >= 9)
        NSLog(@"huge (heavy) touch");
     else
        NSLog(@"little (light) touch");
  }

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