將 UIPanGestureRecognizer 限制為邊界 swift

Question

我在 uicollectionview 單元格中有一個水平滾動的圖像，我想實現像 facebook 和照片應用程序蘋果這樣的功能，您單擊圖像，它會覆蓋整個屏幕。 您可以捏合和平移圖像，我想添加一些限制，例如 facebook 和照片應用程序，例如當您捏合圖片時，您可以最大平移到其寬度。

如果用戶嘗試將圖像移出邊界，我希望圖像再次居中。 我正在添加一些屏幕截圖以提供有關它的想法。

現在我正在使用簡單的代碼。

 guard gestureRecognizer.view != nil else {return}
    print(self.imgView.frame)
    if self.imgView.frame.size.width < (self.imgOrignal.width+100) {
        return
    }

    let piece = gestureRecognizer.view!
    // Get the changes in the X and Y directions relative to
    // the superview's coordinate space.
    let translation = gestureRecognizer.translation(in: piece.superview)
    if gestureRecognizer.state == .began {
        self.initialCenter = piece.center
    }
    // Update the position for the .began, .changed, and .ended states
    if gestureRecognizer.state != .cancelled {
        // Add the X and Y translation to the view's original position.
        let newCenter = CGPoint(x: initialCenter.x + translation.x, y: initialCenter.y + translation.y)
        piece.center = newCenter
    }
    else {
        // On cancellation, return the piece to its original location.
        piece.center = initialCenter
    }
}

Answer 1

我已經通過使用 UIScrollView 放大和縮小解決了這個問題，而不是使用捏和平移手勢，如果有人想要實現該功能，我將在下面添加我的代碼。

  func setZoomScale() {
    let widthScale = self.bgView.frame.size.width / self.imgView.bounds.width
    let heightScale = self.bgView.frame.size.height / self.imgView.bounds.height
    let minScale = min(widthScale, heightScale)
    self.imgScrollView.minimumZoomScale = minScale
    self.imgScrollView.zoomScale = minScale
}


extension YOUR CLASS: UIScrollViewDelegate {

func viewForZooming(in scrollView: UIScrollView) -> UIView? {
    return self.imgView
}

func scrollViewDidZoom(_ scrollView: UIScrollView) {
    let imageViewSize = self.imgView.frame.size
    let scrollViewSize = scrollView.bounds.size
    let verticalInset = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.height) / 2 : 0
    let horizontalInset = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2 : 0
    scrollView.contentInset = UIEdgeInsets(top: verticalInset, left: horizontalInset, bottom: verticalInset, right: horizontalInset)
}

}