我正在使用自定义相机捕获图像。（我正在使用AVCaptureStillImageOutput jpegStillImageNSDataRepresentation将其转换为UIImage）。 我的目标是裁剪图像的特定区域。在我的图像捕获视图中，我绘制了一个具有动态大小的矩形，例如现在width：50px和height：30px，我只想捕获矩形内的区域。
我该怎么做？
答案 0 :(得分：0)
尝试使用此代码，我认为这会对您有所帮助
添加框架：
import GLKit
import CoreImage
//Extension for image
extension UIImage {
func crop( rect: CGRect) -> UIImage {
var rect = rect
rect.origin.x*=self.scale
rect.origin.y*=self.scale
rect.size.width*=self.scale
rect.size.height*=self.scale
let imageRef = self.cgImage!.cropping(to: rect)
let image = UIImage(cgImage: imageRef!, scale: self.scale, orientation: self.imageOrientation)
return image
}
}
extension UIImage {
func fixed() -> UIImage {
let ciContext = CIContext(options: nil)
let cgImg = ciContext.createCGImage(ciImage!, from: ciImage!.extent)
let image = UIImage(cgImage: cgImg!, scale: originalImage.scale, orientation: originalImage.imageOrientation)
return image
}
}
extension CIDetector {
static let rectangle: CIDetector? = {
let detector = CIDetector(ofType: CIDetectorTypeRectangle, context: nil, options: [:])
return detector
}()
static let text: CIDetector? = {
let detector = CIDetector(ofType: CIDetectorTypeText, context: nil, options: [:])
return detector
}()
static let face: CIDetector? = {
let detector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: [:])
return detector
}()
}
extension CIColor {
static let redTone: CIColor = {
return CIColor(red: 1.0, green: 0, blue: 0, alpha: 0.2)
}()
static let blueTone: CIColor = {
return CIColor(red: 0.0, green: 0, blue: 1.0, alpha: 0.3)
}()
}
extension CITextFeature: Measurable {}
extension CIRectangleFeature: Measurable {}
protocol Measurable {
var bounds: CGRect { get }
var topLeft: CGPoint { get }
var topRight: CGPoint { get }
var bottomLeft: CGPoint { get }
var bottomRight: CGPoint { get }
}
extension Measurable {
func perspectiveOverlay(on image: CIImage, with color: CIColor) -> CIImage? {
var overlay = CIImage(color: color)
overlay = overlay.cropped(to: bounds)
overlay = overlay.applyingFilter(
"CIPerspectiveTransformWithExtent",
parameters: [
"inputExtent": CIVector(cgRect: image.extent),
"inputTopLeft": CIVector(cgPoint: topLeft),
"inputTopRight": CIVector(cgPoint: topRight),
"inputBottomLeft": CIVector(cgPoint: bottomLeft),
"inputBottomRight": CIVector(cgPoint: bottomRight)])
return overlay
}
}
private var originalImage = UIImage()
class ViewController: UIViewController{
//Camera Capture requiered properties
var videoDataOutput: AVCaptureVideoDataOutput!
var videoDataOutputQueue: DispatchQueue!
var previewLayer:AVCaptureVideoPreviewLayer!
var captureDevice : AVCaptureDevice!
let session = AVCaptureSession()
var detector : CIDetector?;
var context: CIContext?;
private var rect: CIRectangleFeature = CIRectangleFeature()
var testimatch: CIImage!
fileprivate var testextent: CGRect!
fileprivate let glkView: GLKView = {
let view = GLKView(frame: .zero, context: EAGLContext(api: .openGLES2)!)
view.transform = CGAffineTransform(rotationAngle: .pi / 2)
return view
}()
var imatch: CIImage!
@IBOutlet weak var imageView: UIImageView!
var testMeasurable : Measurable!
private var cropedImage: UIImage!
fileprivate var extent: CGRect!
fileprivate var ciContextt: CIContext!
fileprivate var glContext: EAGLContext!
override func viewDidLoad() {
context = CIContext();
detector = CIDetector(ofType: CIDetectorTypeFace, context: context);
self.setupAVCapture()
}
}
// AVCaptureVideoDataOutputSampleBufferDelegate protocol and related methods
extension ViewController: AVCaptureVideoDataOutputSampleBufferDelegate{
func setupAVCapture(){
session.sessionPreset = AVCaptureSession.Preset.vga640x480
guard let device = AVCaptureDevice
.default(AVCaptureDevice.DeviceType.builtInWideAngleCamera,
for: .video,
position: AVCaptureDevice.Position.back) else {
return
}
captureDevice = device
beginSession()
}
func beginSession(){
var deviceInput: AVCaptureDeviceInput!
do {
deviceInput = try AVCaptureDeviceInput(device: captureDevice)
guard deviceInput != nil else {
print("error: cant get deviceInput")
return
}
if self.session.canAddInput(deviceInput){
self.session.addInput(deviceInput)
}
videoDataOutput = AVCaptureVideoDataOutput()
videoDataOutput.alwaysDiscardsLateVideoFrames=true
videoDataOutputQueue = DispatchQueue(label: "VideoDataOutputQueue")
videoDataOutput.setSampleBufferDelegate(self, queue:self.videoDataOutputQueue)
videoDataOutput!.videoSettings = [kCVPixelBufferPixelFormatTypeKey: Int(kCVPixelFormatType_32BGRA)] as [String : Any]
if session.canAddOutput(self.videoDataOutput){
session.addOutput(self.videoDataOutput)
}
videoDataOutput.connection(with: .video)?.isEnabled = true
// let connection = videoDataOutput.connection(with: .video)
// connection?.videoOrientation = .portrait
previewLayer = AVCaptureVideoPreviewLayer(session: self.session)
previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
let rootLayer :CALayer = self.view.layer
rootLayer.masksToBounds = true
previewLayer.frame = rootLayer.bounds
glkView.frame = rootLayer.bounds
glkView.bindDrawable()
glkView.isOpaque = false
glkView.layer.isOpaque = false
self.previewLayer.addSublayer(glkView.layer)
rootLayer.addSublayer(self.previewLayer)
ciContextt = CIContext(eaglContext: glkView.context)
extent = CGRect(x: -5, y: -60, width: glkView.drawableWidth + 20, height: glkView.drawableHeight + 120)
// extent = CGRect(x: 0, y: 0, width: glkView.drawableWidth , height: glkView.drawableHeight)
session.startRunning()
} catch let error as NSError {
deviceInput = nil
print("error: \(error.localizedDescription)")
}
}
func newimagerect(feature : Measurable) -> UIImage{
let cgimg = self.context?.createCGImage(self.imatch!, from: testimatch!.extent)
originalImage = UIImage(ciImage: self.imatch)
let newImage = UIImage(cgImage: cgimg!, scale: originalImage.scale, orientation: originalImage.imageOrientation)
self.imageView.image = newImage
self.imageView.image?.crop(rect: testextent)
let perspectiveCorrection = CIFilter(name: "CIPerspectiveCorrection")!
let docImage = self.imatch!
perspectiveCorrection.setValue(CIVector(cgPoint:feature.topLeft),
forKey: "inputTopLeft")
perspectiveCorrection.setValue(CIVector(cgPoint:feature.topRight),
forKey: "inputTopRight")
perspectiveCorrection.setValue(CIVector(cgPoint:feature.bottomRight),
forKey: "inputBottomRight")
perspectiveCorrection.setValue(CIVector(cgPoint:feature.bottomLeft),
forKey: "inputBottomLeft")
perspectiveCorrection.setValue(docImage,
forKey: kCIInputImageKey)
let outputImage = perspectiveCorrection.outputImage
let updatedImage = UIImage(ciImage: outputImage!, scale: originalImage.scale, orientation: originalImage.imageOrientation)
cropedImage = updatedImage.fixed()
return cropedImage
}
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
let pixelBuffer : CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!;
var image : CIImage = CIImage(cvPixelBuffer: pixelBuffer);
DispatchQueue.main.async {
self.imatch = image
let stDetect = CIDetector.rectangle?.features(in: image, options: [ CIDetectorAccuracy: CIDetectorAccuracyLow , CIDetectorTracking: true, CIDetectorMinFeatureSize : 0.2]).first.flatMap{ f in
if let feature = f as? Measurable {
feature.perspectiveOverlay(on: image, with: CIColor.redTone).flatMap{
image = $0
self.glkView.isHidden = false
self.testMeasurable = feature
self.draw(image: image)
}
}
}
if stDetect == nil{
self.glkView.isHidden = true
}
}
}
func draw(image: CIImage) {
DispatchQueue.main.async {
//Draw rect
self.glkView.bindDrawable()
if self.glkView.context != EAGLContext.current() {
EAGLContext.setCurrent(self.glkView.context)
}
glClearColor(0.0,0.0,0.0,0.0);
self.ciContextt.draw(image, in: self.extent, from: image.extent)
self.testimatch = image
self.testextent = self.extent
self.glkView.display()
}
}
// clean up AVCapture
func stopCamera(){
session.stopRunning()
}
}
仅通过调用即可从摄像机获取带有矩形的uiimage：
let image = self.newimagerect（feature：self.testMeasurable）