使用UIBezierPath快速裁剪图像
使用UIBezierPath快速裁剪图像
提问于 2018-04-16 16:47:26
我想从图像中裁剪bezier路径。由于某些原因，图像仍然是未剪裁的。我如何定位路径，使其被正确剪切？
extension UIImage {
func imageByApplyingMaskingBezierPath(_ path: UIBezierPath, _ pathFrame: CGFrame) -> UIImage {
UIGraphicsBeginImageContext(self.size)
let context = UIGraphicsGetCurrentContext()!
context.saveGState()
path.addClip()
draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
let maskedImage = UIGraphicsGetImageFromCurrentImageContext()!
context.restoreGState()
UIGraphicsEndImageContext()
return maskedImage
}
}
回答 3
Stack Overflow用户
发布于 2018-04-16 17:05:37
您需要将path.cgPath添加到当前上下文中，还需要删除context.saveGState()和context.restoreGState()
使用此代码
func imageByApplyingMaskingBezierPath(_ path: UIBezierPath, _ pathFrame: CGRect) -> UIImage {
UIGraphicsBeginImageContext(self.size)
let context = UIGraphicsGetCurrentContext()!
context.addPath(path.cgPath)
context.clip()
draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
let maskedImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return maskedImage
}使用it的
let testPath = UIBezierPath()
testPath.move(to: CGPoint(x: self.imageView.frame.width / 2, y: self.imageView.frame.height))
testPath.addLine(to: CGPoint(x: 0, y: 0))
testPath.addLine(to: CGPoint(x: self.imageView.frame.width, y: 0))
testPath.close()
self.imageView.image = UIImage(named:"Image")?.imageByApplyingMaskingBezierPath(testPath, self.imageView.frame)结果
Stack Overflow用户
发布于 2018-04-16 16:59:51
你可以试着这样做。
var path = UIBezierPath()
var shapeLayer = CAShapeLayer()
var cropImage = UIImage()
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first as UITouch?{
let touchPoint = touch.location(in: self.YourimageView)
print("touch begin to : \(touchPoint)")
path.move(to: touchPoint)
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first as UITouch?{
let touchPoint = touch.location(in: self.YourimageView)
print("touch moved to : \(touchPoint)")
path.addLine(to: touchPoint)
addNewPathToImage()
}
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first as UITouch?{
let touchPoint = touch.location(in: self.YourimageView)
print("touch ended at : \(touchPoint)")
path.addLine(to: touchPoint)
addNewPathToImage()
path.close()
}
}
func addNewPathToImage(){
shapeLayer.path = path.cgPath
shapeLayer.strokeColor = strokeColor.cgColor
shapeLayer.fillColor = UIColor.clear.cgColor
shapeLayer.lineWidth = lineWidth
YourimageView.layer.addSublayer(shapeLayer)
}
func cropImage(){
UIGraphicsBeginImageContextWithOptions(YourimageView.bounds.size, false, 1)
tempImageView.layer.render(in: UIGraphicsGetCurrentContext()!)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
self.cropImage = newImage!
}
@IBAction func btnCropImage(_ sender: Any) {
cropImage()
}在特定按钮操作上绘制路径后，只需调用您的imageByApplyingMaskingBezierPath
Stack Overflow用户
发布于 2021-01-02 05:42:38
以下是基于UIBezierPath从图像中获取剪辑的Swift代码，它的实现速度非常快。如果图像已经显示在屏幕上，则此方法有效，这种情况最常见。合成的图像将有一个透明的背景，这是大多数人在剪辑照片图像的一部分时想要的。您可以在本地使用得到的裁剪图像，因为您将把它放在我称为imageWithTransparentBackground的UIImage对象中。这段非常简单的代码还向您展示了如何将图像保存到相机胶卷，以及如何将其直接放到粘贴板中，以便用户可以直接将该图像粘贴到文本消息中，粘贴到便笺、电子邮件等中。请注意，为了将图像写入相机胶卷，您需要编辑info.plist并提供原因，以了解“隐私-图片库使用说明”
import Photos // Needed if you save to the camera roll提供用于裁剪的UIBezierPath。这是我对其中之一的声明。
let clipPath = UIBezierPath()使用一些命令组合，用您自己的一些逻辑填充clipPath。下面是我在绘图逻辑中使用的一些代码。为aPointOnScreen提供CGPoint等效项，等构建相对于主屏幕的路径，因为self.view是此应用程序的ViewController (对于此代码)，并且self.view.layer通过clipPath呈现。
clipPath.move(to: aPointOnScreen)
clipPath.addLine(to: otherPointOnScreen)
clipPath.addLine(to: someOtherPointOnScreen)
clipPath.close()此逻辑使用所有设备屏幕作为上下文大小。为此声明了一个CGSize。fullScreenX和fullScreenY是我已经捕获了设备宽度和高度的变量。如果你正在裁剪的照片已经放大，并且在整个屏幕上显示的大小足够大，那就更好了。你所看到的就是你所得到的。
let mainScreenSize = CGSize(width: fullScreenX, height: fullScreenY)
// Get an empty context
UIGraphicsBeginImageContext(mainScreenSize)
// Specify the clip path
clipPath.addClip()
// Render through the clip path from the whole of the screen.
self.view.layer.render(in: UIGraphicsGetCurrentContext()!)
// Get the clipped image from the context
let image : UIImage = UIGraphicsGetImageFromCurrentImageContext()!
// Done with the context, so end it.
UIGraphicsEndImageContext()
// The PNG data has the alpha channel for the transparent background
let imageData = image.pngData()
// Below is the local UIImage to use within your code
let imageWithTransparentBackground = UIImage.init(data: imageData!)
// Make the image available to the pasteboard.
UIPasteboard.general.image = imageWithTransparentBackground
// Save the image to the camera roll.
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAsset(from: imageWithTransparentBackground!)
}, completionHandler: { success, error in
if success {
//
}
else if let error = error {
//
}
else {
//
}
})页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/49853122
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