在previewLayer上绘图：AVCaptureVideoPreviewLayer
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我有一个小应用程序，一个显示实时（视频）预览的SimpleCamera，屏幕上有一个按钮可以拍照。然后显示照片，您可以保存或丢弃它。一切正常，我使用此代码在屏幕预览周围绘制一个灰色边框。这也很好。但是我可以在预览屏幕上绘制这些内容吗？我无法弄清楚如何添加第一个代码块下面显示的下一位代码？
// Provide a camera preview
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
view.layer.addSublayer(cameraPreviewLayer!)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
cameraPreviewLayer?.frame = view.layer.frame
//Add preview layer for drawing
let previewLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
previewLayer.frame = self.view.layer.frame
previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
self.view.layer.addSublayer(previewLayer)
//Add Rectangle
let cgRect = CGRect(x: 0, y: 0, width: self.view.bounds.width, height: self.view.bounds.height)
let myView = UIImageView()
myView.frame = cgRect
myView.backgroundColor = UIColor.clear
myView.isOpaque = false
myView.layer.cornerRadius = 10
myView.layer.borderColor = UIColor.lightGray.cgColor
myView.layer.borderWidth = 3
myView.layer.masksToBounds = true
previewLayer.addSublayer(myView.layer)
// Bring the camera button to front
view.bringSubview(toFront: cameraButton)
captureSession.startRunning()
无论我把这段代码放在哪里，它都不会显示出来。
//Add circles
let midX = screenWidth / 2
let midY = screenHeight / 2
let w = screenWidth
var circlePath = UIBezierPath(arcCenter: CGPoint(x: midX,y: midY), radius: CGFloat(w * 0.010), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let circleRads = [ 0.07, 0.13, 0.17, 0.22, 0.29, 0.36, 0.40, 0.48, 0.60, 0.75 ]
for pct in circleRads {
let rad = w * CGFloat(pct)
circlePath = UIBezierPath(arcCenter: CGPoint(x: midX, y: midY), radius: CGFloat(rad), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
circlePath.lineWidth = 2.5
circlePath.stroke()
}
// draw text time stamp on image
let now = Date()
let formatter = DateFormatter()
formatter.timeZone = TimeZone.current
formatter.dateFormat = "yyyy-MM-dd HH:mm"
let dateString = formatter.string(from: now)
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .center
let attrs = [NSAttributedStringKey.font: UIFont(name: "HelveticaNeue-Thin", size: 26)!, NSAttributedStringKey.paragraphStyle: paragraphStyle]
let string = dateString
string.draw(with: CGRect(x: 12, y: 38, width: 448, height: 448), options: .usesLineFragmentOrigin, attributes: attrs, context: nil)
答案
部分回答。我可以在整个屏幕上画一个边框。这是来自AppCoda Swift 4中级ios 11 Book的SimpleCamera应用程序。这是CameraController.swift文件的代码，在XCode中打开时，边框绘图部分是第176行到第192行。但我仍然无法弄清楚如何使评论部分绘制一组圆圈，并在图像上放置日期戳，并保存它。
//
// CameraController.swift
// Camera
//
// Created by Simon Ng on 16/10/2016.
// Copyright © 2016 AppCoda. All rights reserved.
//
import UIKit
import AVFoundation
import Foundation
class CameraController: UIViewController {
@IBOutlet var cameraButton:UIButton!
//===================================
@IBOutlet weak var navigationBar: UINavigationBar!
@IBOutlet weak var imgOverlay: UIImageView!
@IBOutlet weak var btnCapture: UIButton!
@IBOutlet weak var btnInfo: UIButton!
@IBOutlet weak var btnSocial: UIButton!
@IBOutlet weak var shapeLayer: UIView!
@IBOutlet weak var btnRed: UIButton!
@IBOutlet weak var btnGreen: UIButton!
@IBOutlet weak var btnBlue: UIButton!
@IBOutlet weak var btnYellow: UIButton!
@IBOutlet weak var btnWhite: UIButton!
//===================================
var backFacingCamera: AVCaptureDevice?
var frontFacingCamera: AVCaptureDevice?
var currentDevice: AVCaptureDevice!
var stillImageOutput: AVCapturePhotoOutput!
var stillImage: UIImage?
var cameraPreviewLayer: AVCaptureVideoPreviewLayer?
let captureSession = AVCaptureSession()
var toggleCameraGestureRecognizer = UISwipeGestureRecognizer()
var zoomInGestureRecognizer = UISwipeGestureRecognizer()
var zoomOutGestureRecognizer = UISwipeGestureRecognizer()
//===============================
//let stillImageOutput = AVCaptureStillImageOutput()
var previewLayer : AVCaptureVideoPreviewLayer?
let screenWidth = UIScreen.main.bounds.size.width
let screenHeight = UIScreen.main.bounds.size.height
var aspectRatio: CGFloat = 1.0
var viewFinderHeight: CGFloat = 0.0
var viewFinderWidth: CGFloat = 0.0
var viewFinderMarginLeft: CGFloat = 0.0
var viewFinderMarginTop: CGFloat = 0.0
var lineColor : UIColor?
var color: Int = 0
//==============================
override func viewDidLoad() {
super.viewDidLoad()
configure()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Action methods
@IBAction func capture(sender: UIButton) {
// Set photo settings
let photoSettings = AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])
photoSettings.isAutoStillImageStabilizationEnabled = true
photoSettings.isHighResolutionPhotoEnabled = true
photoSettings.flashMode = .off
stillImageOutput.isHighResolutionCaptureEnabled = true
stillImageOutput.capturePhoto(with: photoSettings, delegate: self)
}
// MARK: - Segues
@IBAction func unwindToCameraView(segue: UIStoryboardSegue) {
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
if segue.identifier == "showPhoto" {
let photoViewController = segue.destination as! PhotoViewController
photoViewController.image = stillImage
}
}
// MARK: - Helper methods
private func configure() {
// Preset the session for taking photo in full resolution
captureSession.sessionPreset = AVCaptureSession.Preset.photo
// Get the front and back-facing camera for taking photos
let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .unspecified)
for device in deviceDiscoverySession.devices {
if device.position == .back {
backFacingCamera = device
} else if device.position == .front {
frontFacingCamera = device
}
}
currentDevice = backFacingCamera
guard let captureDeviceInput = try? AVCaptureDeviceInput(device: currentDevice) else {
return
}
// Configure the session with the output for capturing still images
stillImageOutput = AVCapturePhotoOutput()
// Configure the session with the input and the output devices
captureSession.addInput(captureDeviceInput)
captureSession.addOutput(stillImageOutput)
// Provide a camera preview
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
view.layer.addSublayer(cameraPreviewLayer!)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
cameraPreviewLayer?.frame = view.layer.frame
//////////////
//Add circles
// red circles - radius in %
/*
let midX = screenWidth / 2
let midY = screenHeight / 2
let w = screenWidth
//let h = screenHeight
var circlePath = UIBezierPath(arcCenter: CGPoint(x: midX,y: midY), radius: CGFloat(w * 0.010), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let circleRads = [ 0.07, 0.13, 0.17, 0.22, 0.29, 0.36, 0.40, 0.48, 0.60, 0.75 ]
for pct in circleRads {
let rad = w * CGFloat(pct)
circlePath = UIBezierPath(arcCenter: CGPoint(x: midX, y: midY), radius: CGFloat(rad), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
circlePath.lineWidth = 2.5
circlePath.stroke()
}
// draw text time stamp on image
let now = Date()
let formatter = DateFormatter()
formatter.timeZone = TimeZone.current
formatter.dateFormat = "yyyy-MM-dd HH:mm"
let dateString = formatter.string(from: now)
// print(dateString)
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.alignment = .center
let attrs = [NSAttributedStringKey.font: UIFont(name: "HelveticaNeue-Thin", size: 26)!, NSAttributedStringKey.paragraphStyle: paragraphStyle]
let string = dateString
string.draw(with: CGRect(x: 22, y: 18, width: 448, height: 448), options: .usesLineFragmentOrigin, attributes: attrs, context: nil)
print("Did the date")
*/
//Add Rectangular border
let previewLayer: AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
previewLayer.frame = self.view.layer.frame
previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
self.view.layer.addSublayer(previewLayer)
let cgRect = CGRect(x: 0, y: 0, width: self.view.bounds.width, height: self.view.bounds.height)
let myView = UIImageView()
myView.frame = cgRect
myView.backgroundColor = UIColor.clear
myView.isOpaque = false
myView.layer.cornerRadius = 10
myView.layer.borderColor = UIColor.lightGray.cgColor
myView.layer.borderWidth = 3
myView.layer.masksToBounds = true
previewLayer.addSublayer(myView.layer)
///////////////
// Bring the camera button to front
view.bringSubview(toFront: cameraButton)
captureSession.startRunning()
print("so far 2")
// Toggle Camera recognizer
toggleCameraGestureRecognizer.direction = .up
toggleCameraGestureRecognizer.addTarget(self, action: #selector(toggleCamera))
view.addGestureRecognizer(toggleCameraGestureRecognizer)
// Zoom In recognizer
zoomInGestureRecognizer.direction = .right
zoomInGestureRecognizer.addTarget(self, action: #selector(zoomIn))
view.addGestureRecognizer(zoomInGestureRecognizer)
// Zoom Out recognizer
zoomOutGestureRecognizer.direction = .left
zoomOutGestureRecognizer.addTarget(self, action: #selector(zoomOut))
view.addGestureRecognizer(zoomOutGestureRecognizer)
}
@objc func toggleCamera() {
captureSession.beginConfiguration()
// Change the device based on the current camera
guard let newDevice = (currentDevice?.position == AVCaptureDevice.Position.back) ? frontFacingCamera : backFacingCamera else {
return
}
// Remove all inputs from the session
for input in captureSession.inputs {
captureSession.removeInput(input as! AVCaptureDeviceInput)
}
// Change to the new input
let cameraInput:AVCaptureDeviceInput
do {
cameraInput = try AVCaptureDeviceInput(device: newD以上是关于在previewLayer上绘图：AVCaptureVideoPreviewLayer的主要内容，如果未能解决你的问题，请参考以下文章