问AVFoundation轻触以聚焦反馈矩形

EN

CameraFocusSquare.h

#import <UIKit/UIKit.h>
@interface CameraFocusSquare : UIView
@end


CameraFocusSquare.m

#import "CameraFocusSquare.h"
#import <QuartzCore/QuartzCore.h>

const float squareLength = 80.0f;
@implementation FBKCameraFocusSquare

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code

        [self setBackgroundColor:[UIColor clearColor]];
        [self.layer setBorderWidth:2.0];
        [self.layer setCornerRadius:4.0];
        [self.layer setBorderColor:[UIColor whiteColor].CGColor];

        CABasicAnimation* selectionAnimation = [CABasicAnimation
                                                animationWithKeyPath:@"borderColor"];
        selectionAnimation.toValue = (id)[UIColor blueColor].CGColor;
        selectionAnimation.repeatCount = 8;
        [self.layer addAnimation:selectionAnimation
                          forKey:@"selectionAnimation"];

    }
    return self;
}
@end

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchPoint = [touch locationInView:touch.view];
    [self focus:touchPoint];

    if (camFocus)
    {
        [camFocus removeFromSuperview];
    }
    if ([[touch view] isKindOfClass:[FBKVideoRecorderView class]])
    {
        camFocus = [[CameraFocusSquare alloc]initWithFrame:CGRectMake(touchPoint.x-40, touchPoint.y-40, 80, 80)];
        [camFocus setBackgroundColor:[UIColor clearColor]];
        [self addSubview:camFocus];
        [camFocus setNeedsDisplay];

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:1.5];
        [camFocus setAlpha:0.0];
        [UIView commitAnimations];
    }
}

- (void) focus:(CGPoint) aPoint;
{
    Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");
    if (captureDeviceClass != nil) {
        AVCaptureDevice *device = [captureDeviceClass defaultDeviceWithMediaType:AVMediaTypeVideo];
        if([device isFocusPointOfInterestSupported] &&
           [device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
            CGRect screenRect = [[UIScreen mainScreen] bounds];
            double screenWidth = screenRect.size.width;
            double screenHeight = screenRect.size.height;
            double focus_x = aPoint.x/screenWidth;
            double focus_y = aPoint.y/screenHeight;
            if([device lockForConfiguration:nil]) {
                [device setFocusPointOfInterest:CGPointMake(focus_x,focus_y)];
                [device setFocusMode:AVCaptureFocusModeAutoFocus];
                if ([device isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
                    [device setExposureMode:AVCaptureExposureModeAutoExpose];
                }
                [device unlockForConfiguration];
            }
        }
    }
}

@objc func didTapToFocus(gesture: UITapGestureRecognizer) {
    let pointInViewCoordinates = gesture.location(in: gesture.view)
    let pointInCameraCoordinates = cameraView.videoPreviewLayer.captureDevicePointConverted(fromLayerPoint: pointInViewCoordinates)
    camera.focusOn(pointInCameraCoordinates: pointInCameraCoordinates)
    cameraView.showFocusBox(at: pointInViewCoordinates)
}

final class CameraFocusBoxView: UIView {

    // MARK: - Instantiation

    init() {
        super.init(frame: .zero)

        backgroundColor = .clear
        layer.addSublayer(focusBoxLayer)
    }

    // MARK: - API

    /// This zooms/fades in a focus square and blinks it a few times, then slowly fades it out
    func showBox(at point: CGPoint) {
        focusBoxLayer.removeAllAnimations()
        let scaleKey = "zoom in focus box"
        let fadeInKey = "fade in focus box"
        let pulseKey = "pulse focus box"
        let fadeOutKey = "fade out focus box"
        guard focusBoxLayer.animation(forKey: scaleKey) == nil,
              focusBoxLayer.animation(forKey: fadeInKey) == nil,
              focusBoxLayer.animation(forKey: pulseKey) == nil,
              focusBoxLayer.animation(forKey: fadeOutKey) == nil
            else { return }

        CATransaction.begin()
        CATransaction.setDisableActions(true)
        focusBoxLayer.position = point
        CATransaction.commit()

        let scale = CABasicAnimation(keyPath: "transform.scale")
        scale.fromValue = 1
        scale.toValue = 0.375
        scale.duration = 0.3
        scale.isRemovedOnCompletion = false
        scale.fillMode = .forwards

        let opacityFadeIn = CABasicAnimation(keyPath: "opacity")
        opacityFadeIn.fromValue = 0
        opacityFadeIn.toValue = 1
        opacityFadeIn.duration = 0.3
        opacityFadeIn.isRemovedOnCompletion = false
        opacityFadeIn.fillMode = .forwards

        let pulsing = CABasicAnimation(keyPath: "borderColor")
        pulsing.toValue = UIColor(white: 1, alpha: 0.5).cgColor
        pulsing.repeatCount = 2
        pulsing.duration = 0.2
        pulsing.beginTime = CACurrentMediaTime() + 0.3 // wait for the fade in to occur

        let opacityFadeOut = CABasicAnimation(keyPath: "opacity")
        opacityFadeOut.fromValue = 1
        opacityFadeOut.toValue = 0
        opacityFadeOut.duration = 0.5
        opacityFadeOut.beginTime = CACurrentMediaTime() + 2 // seconds
        opacityFadeOut.isRemovedOnCompletion = false
        opacityFadeOut.fillMode = .forwards

        focusBoxLayer.add(scale, forKey: scaleKey)
        focusBoxLayer.add(opacityFadeIn, forKey: fadeInKey)
        focusBoxLayer.add(pulsing, forKey: pulseKey)
        focusBoxLayer.add(opacityFadeOut, forKey: fadeOutKey)
    }

    // MARK: - Private Properties

    private lazy var focusBoxLayer: CALayer = {
        let box = CALayer()
        box.bounds = CGRect(x: 0, y: 0, width: 200, height: 200)
        box.borderWidth = 2
        box.borderColor = UIColor.white.cgColor
        box.opacity = 0
        return box
    }()

    // MARK: - Unsupported Initializers

    required init?(coder aDecoder: NSCoder) { fatalError("init(coder:) has not been implemented") }

}