swift - UIImageView 上的捏合、平移和双击手势
问题描述
我想在具有以下限制的图像视图上应用这些手势:
1)双击:缩放图像两次,然后返回原始大小
2)捏:缩放图像与原始大小的最大限制和最小限制
3)平移:缩放图像时,移动图像和图像视图不应超过边界之一
我使用教程尝试了以下代码,但平移无法正常工作,我认为有时也会影响其他手势:
请让我知道我做错了什么。
特性:
var originalFrame = CGRect()
var initialCenter = CGPoint() // The initial center point of the view.
var imgTapCount = 0
var lastScale: CGFloat = 1.0
var minScale = 1.0
var maxScale = 4.0
var imageCurrentScale = 1.0
在viewDidLoad()
我调用以下函数
func displayImage() {
//imgView gets image assigned here from Url
originalFrame = imgView.frame
}
点击手势:
@IBAction func imgTapGesture(_ sender: UITapGestureRecognizer) {
guard sender.view != nil else {return}
if imgTapCount < 2 {
let pinchCenter = CGPoint(x: sender.location(in: view).x - view.bounds.midX,
y: sender.location(in: view).y - view.bounds.midY)
let transform = sender.view?.transform.translatedBy(x: pinchCenter.x, y: pinchCenter.y)
.scaledBy(x: 2, y: 2)
.translatedBy(x: -pinchCenter.x, y: -pinchCenter.y)
sender.view?.transform = transform!
} else {
UIView.animate(withDuration: 0.2, animations: {
sender.view?.transform = CGAffineTransform.identity
})
}
if imgTapCount < 2 {
imgTapCount += 1
} else {
imgTapCount = 0
}
}
平移手势
@IBAction func imgPanGesture(_ sender: UIPanGestureRecognizer) {
guard sender.view != nil else {return}
let piece = sender.view!
// Get the changes in the X and Y directions relative to
// the superview's coordinate space.
let translation = sender.translation(in: piece.superview)
if sender.state == .began {
// Save the view's original position.
self.initialCenter = piece.center
}
// Update the position for the .began, .changed, and .ended states
if sender.state != .cancelled {
// Add the X and Y translation to the view's original position.
if (imgView.frame.width > piece.superview!.frame.width || imgView.frame.height > piece.superview!.frame.height) && (((imgView.frame.minX <= originalFrame.minX) || (imgView.frame.maxX >= originalFrame.maxX)) || (imgView.frame.minY <= originalFrame.minY) || (imgView.frame.maxY >= originalFrame.maxY)) {
let newCenter = CGPoint(x: initialCenter.x + translation.x, y: initialCenter.y + translation.y)
print(newCenter)
piece.center = newCenter
}
} else {
// On cancellation, return the piece to its original location.
piece.center = initialCenter
}
}
捏手势
@IBAction func imgPinchGesture(_ sender: UIPinchGestureRecognizer) {
var newScale = sender.scale
if sender.state == .began {
lastScale = self.imgView.frame.width/self.imgView.bounds.size.width
}
newScale = newScale * lastScale
if newScale < minScale {
newScale = minScale
} else if newScale > maxScale {
newScale = maxScale
}
let currentScale = self.imgView.frame.width/self.imgView.bounds.size.width
self.imgView.transform = CGAffineTransform(scaleX: newScale, y: newScale)
print("last Scale: \(lastScale), current scale: \(currentScale), new scale: \(newScale), gestureRecognizer.scale: \(sender.scale)")
}
解决方案
lazy var pdfView: PDFView = {
let pdfView = PDFView()
pdfView.displaysPageBreaks = true
pdfView.enableDataDetectors = true
pdfView.subviews[0].backgroundColor = .clear
pdfView.maxScaleFactor = 4
return pdfView
}()
然后在声明 pdf 视图后,您应该添加一个将图像转换为 pdfdocument 的函数
func createPDF(image: UIImage) -> PDFDocument {
let document = PDFDocument()
guard let cgImage = image.cgImage else { return document }
let image = UIImage(cgImage: cgImage, scale: image.scale, orientation: .downMirrored)
guard let imagePDF = PDFPage(image: image) else { return document }
document.insert(imagePDF, at: document.pageCount)
return document
}
之后在 viewDidAppear 中 subview your pdf in view ...您可以将此 pdfDocument 分配给您的 pdf
pdfView.document = createPDF(image: "yourImage")
pdfView.autoScale = true
推荐阅读
- python - Mayavi Python 如何对每个 3D 顶点进行不同的染色
- matlab - MATLAB:fsolve 错误“输入参数不足”
- pdf - PDF 未将马拉地语数据正确发布到服务器
- spring - 使用 Spring Data JPA 时不显示 JSP 错误消息
- c# - 指向同一视图的多个链接,但根据值动态显示数据?
- python - pytest-django 找不到 Django 项目
- android - 在数组适配器中创建新片段
- node.js - 路线未正确定向
- javascript - 获取 td 值并使用 JQuery 与输入值进行比较
- javascript - 仅显示客户服务功能 页面底部的移动视图和滚动条