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如何检测鼠标/手指是否沿着特定路径移动？

发布于 2024-07-15 06:02:41 字数 118 浏览 3 评论 0原文

我正在为 iPhone 开发一个应用程序，我想检测用户何时沿着特定路径移动手指。

具体来说，我想检测用户何时沿着特定的圆形路径移动手指。

这可能很容易通过检测鼠标沿路径的运动来适应。

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不羁少年 2024-07-22 06:02:41

似乎特定案例的实施起来相当简单。将输入区域分为四个象限并跟踪每个象限的位置。象限的顺序决定了它们是否已经完成或绕了一圈。

描述这个想法的伪代码：

static touchKeeper; //touch, quadrant
static touchIndex=0;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
   UITouch *touch = [[allTouches allObjects] objectAtIndex:0];
   touchKeeper[touchIndex].touch =  touch;
   touchKepper[touchIndex].quadrant = DetectQuadrant(touch));
   if (touchIndex > 3 && (touchKeeper[3].quadrant == touchKeeper[2].quadrant+1 == touchKeeper[1].quadrant+2 == touchKeeper[0].quadrant+3)) {
     [self doCircleAction];
     touchIndex=0;
   } 
     else touchIndex++;
 }

这个想法是你只需要粗略地识别一个区域的特定触摸。所以象限例程会是这样的：

int DetectQuadrant(UITouch *touch) {
 CGPoint point;
 point = [touch locationInView:self];
 if (endPoint.x > X1 && endPoint.x < X2 && endPoint.Y > Y1 && endPoint.Y < Y2)
  return QUAD1;
 } else etc

我使用象限作为例子 - 显然你可以画一个正方形并认为“圆形！”。通过在 Detect 方法中创建更多区域来提高准确性。主要思想是根据区域序列进行思考，以便实现所需的行为，而不会过度复杂化（如贝塞尔曲线检测或类似的废话）。这个伪代码肯定是粗暴的，我确信有一个很好的方法来巧妙地实现。我一直在为我正在从事的一个项目考虑“圆周运动检测”，这是我想出的粗略想法。

享受！

Seems like a specific case can be fairly simple to implement. Divide the input area into four quadrants and track the position through each quadrant. The sequence of quandrants determines if they have completed or traveled in a circle.

Pseudo-code to describe the idea:

static touchKeeper; //touch, quadrant
static touchIndex=0;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
   UITouch *touch = [[allTouches allObjects] objectAtIndex:0];
   touchKeeper[touchIndex].touch =  touch;
   touchKepper[touchIndex].quadrant = DetectQuadrant(touch));
   if (touchIndex > 3 && (touchKeeper[3].quadrant == touchKeeper[2].quadrant+1 == touchKeeper[1].quadrant+2 == touchKeeper[0].quadrant+3)) {
     [self doCircleAction];
     touchIndex=0;
   } 
     else touchIndex++;
 }

The idea is that you only need to roughly identify a particular touch to a region. So the quadrant routine would something like this:

int DetectQuadrant(UITouch *touch) {
 CGPoint point;
 point = [touch locationInView:self];
 if (endPoint.x > X1 && endPoint.x < X2 && endPoint.Y > Y1 && endPoint.Y < Y2)
  return QUAD1;
 } else etc

I use quadrants as an example - clearly you could draw a square and think 'circle!'. The accuracy is improved by making more regions in the Detect method. The main idea is to think in terms of sequences of regions in order to achieve the desired behavior without excessive complication (like bezier curve detection or similar nonsense). This pseudo code is certainly brutish and I'm sure there's a nice way to finesse the implementation. I've been thinking about 'circular motion detection' for a project I'm working on and this was the rough idea I came up with.

Enjoy!

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