想要限制一个 imageView swift 5 上的平移手势区域

如何解决想要限制一个 imageView swift 5 上的平移手势区域

我有一个 imageview，它有 2 个gestureRecognizers 1)捏 2)平移

我可以使用缩放属性捏合图像和缩放 我无法实现的是，当我缩放该图像并拖动到所有 4 个边时，我可以拖动图像并且我能够看到图像视图后面的背景视图 想要限制图像视图的拖动，直到显示缩放图像

这是捏和平移手势的代码

  @objc func pinchRecognized(pinch: UIPinchGestureRecognizer) {

            if let view = pinch.view {
                view.transform = view.transform.scaledBy(x: pinch.scale,y: pinch.scale)
                pinch.scale = 1
            }
        }
    
    @objc func PangestureMethod(gestureRecognizer: UIPanGestureRecognizer){
       guard gestureRecognizer.view != nil else {return}
       let piece = gestureRecognizer.view!
  
    
       let translation = gestureRecognizer.translation(in: piece.superview)
        
       if gestureRecognizer.state == .began {
          self.initialCenter = piece.center
       }
       if gestureRecognizer.state != .cancelled {
          let newCenter = CGPoint(x: initialCenter.x + translation.x,y: initialCenter.y + translation.y)
          piece.center = newCenter
       }
       else {
          piece.center = initialCenter
       }
    }

解决方法

首先，重置平移手势的平移（可能）更容易，因此我们正在计算相对运动：

if gestureRecognizer.state != .cancelled {
    
    // translation will be + or - a small number of points
    // do what's needed to move the view

    // reset recognizer
    gestureRecognizer.setTranslation(.zero,in: superV)

}

否则，假设您向右拖动（平移）300 点，但视图只能移动 20 点，然后它不会开始向左移动，直到您向左拖动 280 点。>

因此，当水平拖动时，我们希望在拖动视图位于其超级视图的左侧或右侧边缘时停止...

• 计算最大 centerX 位置
  • 这将是拖动视图宽度的 1/2
• 计算最小 centerX 位置
  • 这将是 superView 的宽度减去拖动视图宽度的 1/2

举个例子，如果superView的宽度是100，而drag-view的宽度是200，则MAX centerX将为100，MIN centerX为{{1 }}。

然后我们对 centerY 位置做同样的事情。

尝试将其用作平移手势处理程序：

Zero

---

编辑

为了防止捏合手势将视图缩小到小于其超级视图框架，我们可以在应用之前将手势的新缩放值应用到视图框架的@objc func PangestureMethod(gestureRecognizer: UIPanGestureRecognizer){ // unwrap the view from the gesture // AND // unwrap that view's superView guard let piece = gestureRecognizer.view,let superV = piece.superview else { return } let translation = gestureRecognizer.translation(in: superV) if gestureRecognizer.state == .began { self.initialCenter = piece.center } if gestureRecognizer.state != .cancelled { // what the new centerX and centerY will be var newX: CGFloat = piece.center.x + translation.x var newY: CGFloat = piece.center.y + translation.y // MAX centerX is 1/2 the width of the piece's frame let mxX = piece.frame.width * 0.5 // MIN centerX is Width of superView minus 1/2 the width of the piece's frame let mnX = superV.bounds.width - piece.frame.width * 0.5 // make sure new centerX is neither greater than MAX nor less than MIN newX = max(min(newX,mxX),mnX) // MAX centerY is 1/2 the height of the piece's frame let mxY = piece.frame.height * 0.5 // MIN centerY is Height of superView minus 1/2 the height of the piece's frame let mnY = superV.bounds.height - piece.frame.height * 0.5 // make sure new centerY is neither greater than MAX nor less than MIN newY = max(min(newY,mxY),mnY) // set the new center piece.center = CGPoint(x: newX,y: newY) // reset recognizer gestureRecognizer.setTranslation(.zero,in: superV) } else { piece.center = initialCenter } } 到视图中。

然后，如果生成的矩形不小于 superView 的框架，则仅将缩放应用于视图。

试试这个：

CGRect