ios - 可以将类型 '__NSArray0' 的值转换为 'CIRectangleFeature'

Question

我一直在 Objective C 中使用一些代码，对在 AVCaptureStillImageOutput 中捕获的 CIImage 执行 CIDetector。我的目标是将其转换为 swift 3。我已将其全部转换为 swift 3，但我在我的 CIRectangleFeature 方法中收到了 this Could not cast 错误。所以我来这里寻求帮助，因为我已经为此工作好几天了，但无法做好。我确信这是我忽略的简单事情。

这是 Objective C 中的代码

- (CIRectangleFeature *)_biggestRectangleInRectangles:(NSArray     *)rectangles
{
if (!rectangles.count) return nil;

float halfPerimiterValue = 0;

CIRectangleFeature *biggestRectangle = rectangles.firstObject;

for (CIRectangleFeature *rect in rectangles)
{
    CGPoint p1 = rect.topLeft;
    CGPoint p2 = rect.topRight;
    CGFloat width = hypotf(p1.x - p2.x, p1.y - p2.y);

    CGPoint p3 = rect.topLeft;
    CGPoint p4 = rect.bottomLeft;
    CGFloat height = hypotf(p3.x - p4.x, p3.y - p4.y);

    CGFloat currentHalfPerimiterValue = height + width;

    if (halfPerimiterValue < currentHalfPerimiterValue)
    {
        halfPerimiterValue = currentHalfPerimiterValue;
        biggestRectangle = rect;
    }
}

return biggestRectangle;

}

这个函数被另一个函数调用，这里是 Objective C 中的

- (CIRectangleFeature *)biggestRectangleInRectangles:(NSArray *)rectangles
{
    CIRectangleFeature *rectangleFeature = [self _biggestRectangleInRectangles:rectangles];

现在，如果 if 像这样返回 true

if (self.isBorderDetectionEnabled)
{
    if (_borderDetectFrame)
    {
        _borderDetectLastRectangleFeature = [self biggestRectangleInRectangles:[[self highAccuracyRectangleDetector] featuresInImage:image]];
        _borderDetectFrame = NO;
    }

它也在另一种方法中被调用，该方法捕获图像并以基本相同的方式保存它们

现在我把它翻译成这样的 swift 3

func bigRectangle(rectangles: [Any]) -> CIRectangleFeature {


    var halfPerimiterValue: Float = 0
    var biggestRectangles: CIRectangleFeature? = rectangles.first as! CIRectangleFeature? // This is the line causing the casting error
    for rect: CIRectangleFeature in rectangles as! [CIRectangleFeature]{
        let p1: CGPoint = rect.topLeft
        let p2: CGPoint = rect.topRight
        let width: CGFloat = CGFloat(hypotf(Float(p1.x) - Float(p2.x), Float(p1.y) - Float(p2.y)))
        let p3: CGPoint = rect.topLeft
        let p4: CGPoint = rect.bottomLeft
        let height: CGFloat = CGFloat(hypotf(Float(p3.x) - Float(p4.x), Float(p3.y) - Float(p4.y)))
        let currentHalfPerimiterValue: CGFloat = height + width
        if halfPerimiterValue < Float(currentHalfPerimiterValue) {
            halfPerimiterValue = Float(currentHalfPerimiterValue)
            biggestRectangles = rect
        }
    }
    return biggestRectangles!
}

我在 swift 3 中调用它基本上与 Objective C 的方式相同

func biggestRectangle(rectangles: [Any]) -> CIRectangleFeature {
    let rectangleFeature: CIRectangleFeature? = self.bigRectangle(rectangles: rectangles)

该函数的调用方式与 Objective C 中的调用方式相同。

if self.isEnableBorderDetection == true{
        if self.borderDetectFrames == true {
            self.borderDetectLastRectangleFeature = self.biggestRectangle(rectangles: [self.highAccuracyRectangleDetector().features(in: image)])
            self.borderDetectFrames = false
        }

从函数内部 func captureOutput(_ captureOutput: AVCaptureOutput, didOutputSampleBuffer SampleBuffer: CMSampleBuffer?, from connection: AVCaptureConnection) {}

现在我尝试在两个函数中将数组类型从 [Any] 更改为 [CIRectangleFeature]，但随后我遇到了 CIFeature 问题是一个不相关的类型。

希望有人能看一下这个并为我指出正确的方向。预先感谢您的帮助。

Answer 1

UPD

您在数组中使用双重包装:

let rectangleFeature: CIRectangleFeature? = self.biggestRectangle(rectangles: [self.highAccuracyRectangleDetector().features(in: enhancedImage!)])