Представление CIRectangleFeature с UIBezierPath - Swift

Ответ 1

Я боролся с той же проблемой в течение нескольких дней, и именно так я преодолел проблему:

Я создал собственный класс для хранения точек и добавления вспомогательных функций:

//
//  ObyRectangleFeature.swift
//
//  Created by 4oby on 5/20/16.
//  Copyright © 2016 cvv. All rights reserved.
//

import Foundation
import UIKit

extension CGPoint {
    func scalePointByCeficient(ƒ_x: CGFloat, ƒ_y: CGFloat) -> CGPoint {
        return CGPoint(x: self.x/ƒ_x, y: self.y/ƒ_y) //original image
    }

    func reversePointCoordinates() -> CGPoint {
        return CGPoint(x: self.y, y: self.x)
    }

    func sumPointCoordinates(add: CGPoint) -> CGPoint {
        return CGPoint(x: self.x + add.x, y: self.y + add.y)
    }

    func substractPointCoordinates(sub: CGPoint) -> CGPoint {
        return CGPoint(x: self.x - sub.x, y: self.y - sub.y)
    }
}

class ObyRectangleFeature : NSObject {

    var topLeft: CGPoint!
    var topRight: CGPoint!
    var bottomLeft: CGPoint!
    var bottomRight: CGPoint!

    var centerPoint : CGPoint{
        get {
            let centerX = ((topLeft.x + bottomLeft.x)/2 + (topRight.x + bottomRight.x)/2)/2
            let centerY = ((topRight.y + topLeft.y)/2 + (bottomRight.y + bottomLeft.y)/2)/2
            return CGPoint(x: centerX, y: centerY)
        }

    }

    convenience init(_ rectangleFeature: CIRectangleFeature) {
        self.init()
        topLeft = rectangleFeature.topLeft
        topRight = rectangleFeature.topRight
        bottomLeft = rectangleFeature.bottomLeft
        bottomRight = rectangleFeature.bottomRight
    }

    override init() {
        super.init()
    }


    func rotate90Degree() -> Void {

        let centerPoint =  self.centerPoint

//        /rotate cos(90)=0, sin(90)=1
        topLeft = CGPoint(x: centerPoint.x + (topLeft.y - centerPoint.y), y: centerPoint.y + (topLeft.x - centerPoint.x))
        topRight = CGPoint(x: centerPoint.x + (topRight.y - centerPoint.y), y: centerPoint.y + (topRight.x - centerPoint.x))
        bottomLeft = CGPoint(x: centerPoint.x + (bottomLeft.y - centerPoint.y), y: centerPoint.y + (bottomLeft.x - centerPoint.x))
        bottomRight = CGPoint(x: centerPoint.x + (bottomRight.y - centerPoint.y), y: centerPoint.y + (bottomRight.x - centerPoint.x))
    }

    func  scaleRectWithCoeficient(ƒ_x: CGFloat, ƒ_y: CGFloat) -> Void {
        topLeft =  topLeft.scalePointByCeficient(ƒ_x, ƒ_y: ƒ_y)
        topRight = topRight.scalePointByCeficient(ƒ_x, ƒ_y: ƒ_y)
        bottomLeft = bottomLeft.scalePointByCeficient(ƒ_x, ƒ_y: ƒ_y)
        bottomRight = bottomRight.scalePointByCeficient(ƒ_x, ƒ_y: ƒ_y)
    }

    func correctOriginPoints() -> Void {

        let deltaCenter = self.centerPoint.reversePointCoordinates().substractPointCoordinates(self.centerPoint)

        let TL = topLeft
        let TR = topRight
        let BL = bottomLeft
        let BR = bottomRight

        topLeft = BL.sumPointCoordinates(deltaCenter)
        topRight = TL.sumPointCoordinates(deltaCenter)
        bottomLeft = BR.sumPointCoordinates(deltaCenter)
        bottomRight = TR.sumPointCoordinates(deltaCenter)
    }
}

И это код инициализации:

let scalatedRect : ObyRectangleFeature = ObyRectangleFeature(rectangleFeature)
        // fromSize -> Initial size of the CIImage
        // toSize -> the size of the scaled Image
        let ƒ_x = (fromSize.width/toSize.width)
        let ƒ_y = (fromSize.height/toSize.height)

        /*the coeficients are interchange intentionally cause of the different
        coordinate system used by CIImage and UIImage, you could rotate before 
        scaling, to preserve the order, but if you do, the result will be offCenter*/

        scalatedRect.scaleRectWithCoeficient(ƒ_y, ƒ_y: ƒ_x)
        scalatedRect.rotate90Degree()
        scalatedRect.correctOriginPoints()

В этот момент scaleRect готов к рисованию любым способом.

Ответ 2

Если вам нужно всего лишь отобразить путь, тогда немного проще нарисовать путь в CAShapeLayer.

• Добавить CAShapeLayer в изображение предварительного просмотра.
• Вычислить прямоугольник.
• Создайте UIBezierPath для этой функции.
• Преобразование пути в соответствие исходному изображению.
• Задайте путь к CAShapeLayer

Некоторые осложнения возникают на шаге 4, если вам нужно поддерживать масштабированные изображения или изображения с ориентацией (т.е. что-либо из пользовательской камеры).

Ниже приведен пример. Это поддерживает Этот код предполагает, что изображение отображается в UIImageView с contentMode AspectFit, AspectFill, ScaleToFill или Center. Он также поддерживает изображения с ориентацией вверх, вниз, вправо и влево.

// Extension for calculating the image scale in an image view.
// See: http://stackoverflow.com/questions/6856879/iphone-getting-the-size-of-an-image-after-aspectft
extension UIImageView {

    var imageScale: CGSize? {

        guard let image = image else {
            return nil
        }

        let sx = Double(self.frame.size.width / image.size.width)
        let sy = Double(self.frame.size.height / image.size.height)
        var s = 1.0
        switch (self.contentMode) {
        case .ScaleAspectFit:
            s = fmin(sx, sy)
            return CGSize (width: s, height: s)

        case .ScaleAspectFill:
            s = fmax(sx, sy)
            return CGSize(width:s, height:s)

        case .ScaleToFill:
            return CGSize(width:sx, height:sy)

        default:
            return CGSize(width:s, height:s)
        }
    }
}

// Extension which provides a transform to rotate the image based on it orientation metadata. 
extension UIImageView {

    var normalizedTransformForOrientation: CGAffineTransform? {

        guard let image = image else {
            return nil
        }

        let r: CGFloat

        switch image.imageOrientation {

        case .Up:
            r = 0

        case .Down:
            r = +1.0

        case .Left:
            r = -0.5

        case .Right:
            r = +0.5

        default:
            fatalError()
        }

        let cx = CGRectGetMidX(bounds)
        let cy = CGRectGetMidY(bounds)

        var transform = CGAffineTransformIdentity
        transform = CGAffineTransformTranslate(transform, cx, cy)
        transform = CGAffineTransformRotate(transform, CGFloat(M_PI) * r)
        transform = CGAffineTransformTranslate(transform, -cx, -cy)
        return transform
    }
}

class ViewController: UIViewController {

    // Shape layer for displaying the path.
    let pathLayer: CAShapeLayer = {
        let layer = CAShapeLayer()
        layer.fillColor = UIColor.greenColor().colorWithAlphaComponent(0.3).CGColor
        layer.strokeColor = UIColor.greenColor().colorWithAlphaComponent(0.9).CGColor
        layer.lineWidth = 2.0
        return layer
    }()

    // Image view where the preview and path overlay will be displayed.
    @IBOutlet var imageView: UIImageView?

    override func viewDidLoad() {

        super.viewDidLoad()

        // Add the path overlay to the image view.
        imageView?.layer.addSublayer(pathLayer)

        // Load a sample image from the assets.
        selectImage(UIImage(named: "sample"))
    }

    func selectImage(image: UIImage?) {

        imageView?.image = image

        if let image = image {
            processImage(image)
        }
    }

    // Detect rectangles in image, and draw the path on the screen.
    func processImage(input: UIImage) {

        let path = pathsForRectanglesInImage(input)

        let transform = pathTransformForImageView(imageView!)
        path?.applyTransform(transform)

        pathLayer.path = path?.CGPath
    }

    // Detect rectangles in an image and return a UIBezierPath.
    func pathsForRectanglesInImage(input: UIImage) -> UIBezierPath? {

        guard let sourceImage = CIImage(image: input) else {
            return nil
        }

        let features = performRectangleDetection(sourceImage)

        return pathForFeatures(features)
    }

    // Detect rectangles in image.
    func performRectangleDetection(image: CIImage) -> [CIFeature] {

        let detector:CIDetector = CIDetector(
            ofType: CIDetectorTypeRectangle,
            context: nil,
            options: [CIDetectorAccuracy : CIDetectorAccuracyHigh]
        )

        let features = detector.featuresInImage(image)

        return features
    }

    // Compose a UIBezierPath from CIRectangleFeatures. 
    func pathForFeatures(features: [CIFeature]) -> UIBezierPath {

        let path = UIBezierPath()

        for feature in features {

            guard let rect = feature as? CIRectangleFeature else {
                continue
            }

            path.moveToPoint(rect.topLeft)
            path.addLineToPoint(rect.topRight)
            path.addLineToPoint(rect.bottomRight)
            path.addLineToPoint(rect.bottomLeft)
            path.closePath()
        }

        return path
    }

    // Calculate the transform to orient the preview path to the image shown inside the image view.
    func pathTransformForImageView(imageView: UIImageView) -> CGAffineTransform {

        guard let image = imageView.image else {
            return CGAffineTransformIdentity
        }

        guard let imageScale = imageView.imageScale else {
            return CGAffineTransformIdentity
        }

        guard let imageTransform = imageView.normalizedTransformForOrientation else {
            return CGAffineTransformIdentity
        }

        let frame = imageView.frame

        let imageWidth = image.size.width * imageScale.width
        let imageHeight = image.size.height * imageScale.height

        var transform = CGAffineTransformIdentity

        // Rotate to match the image orientation.
        transform = CGAffineTransformConcat(imageTransform, transform)

        // Flip vertically (flipped in CIDetector).
        transform = CGAffineTransformTranslate(transform, 0, CGRectGetHeight(frame))
        transform = CGAffineTransformScale(transform, 1.0, -1.0)

        // Centre align.
        let tx: CGFloat = (CGRectGetWidth(frame) - imageWidth) * 0.5
        let ty: CGFloat = (CGRectGetHeight(frame) - imageHeight) * 0.5
        transform = CGAffineTransformTranslate(transform, tx, ty)

        // Scale to match UIImageView scaling.
        transform = CGAffineTransformScale(transform, imageScale.width, imageScale.height)

        return transform
    }
}

Ответ 3

Координаты прямоугольника, возвращаемые из CIDetector, относятся к CIImage, на котором он обнаруживает - это координаты изображения. Чтобы использовать эти координаты с UIBezierPath, нам нужно выполнить ряд преобразований.

Во-первых, мы должны найти отношение кадра предварительного просмотра камеры к размеру CIImage, который использует CIRectangleFeature.

Затем, с этим соотношением, мы должны перевернуть скорректированные координаты, так как Core Image (CIImage) использует другую систему координат, чем Core Animation (CALayer/UIBezierPath).

Итак:

 CGRect previewRect = self.frame;
 CGRect imageRect = image.extent;

 // find ratio between the video preview rect and the image rect; rectangle feature coordinates are relative to the CIImage
 CGFloat deltaX = CGRectGetWidth(previewRect)/CGRectGetWidth(imageRect);
 CGFloat deltaY = CGRectGetHeight(previewRect)/CGRectGetHeight(imageRect);

 // transform to UIKit coordinate system
 CGAffineTransform transform = CGAffineTransformMakeTranslation(0.f, CGRectGetHeight(previewRect));
 transform = CGAffineTransformScale(transform, 1, -1);
 // apply preview to image scaling
 transform = CGAffineTransformScale(transform, deltaX, deltaY);

 CGPoint points[4];
 points[0] = CGPointApplyAffineTransform(_borderDetectLastRectangleFeature.topLeft, transform);
 points[1] = CGPointApplyAffineTransform(_borderDetectLastRectangleFeature.topRight, transform);
 points[2] = CGPointApplyAffineTransform(_borderDetectLastRectangleFeature.bottomRight, transform);
 points[3] = CGPointApplyAffineTransform(_borderDetectLastRectangleFeature.bottomLeft, transform);


UIBezierPath *path = [UIBezierPath new];
[path moveToPoint:points[0]];
[path addLineToPoint:points[1]];
[path addLineToPoint:points[2]];
[path addLineToPoint:points[3]];
[path addLineToPoint:points[0]];
[path closePath];

CAShapeLayer *_shapeLayer = [CAShapeLayer layer];
_shapeLayer.fillColor = [UIColor colorWithRed:.5 green:1 blue:.5 alpha:.6f].CGColor;
_shapeLayer.strokeColor = [UIColor blackColor].CGColor;
_shapeLayer.lineWidth = 2;
_shapeLayer.path = path.CGPath;
[self.layer addSublayer:_shapeLayer];