ios - 如何在 Mapbox 3.6 中旋转汽车标记图像？

我想根据路线方向旋转标记图像。我已经使用 Map box SDK 实现了 map 。坐标和方向是通过网络服务获取的。 我尝试了 imageForMarker 但它没有用。实现如下

func mapView(_ mapView: MGLMapView, imageFor annotation: MGLAnnotation) -> MGLAnnotationImage? {

    let img = imageRotatedByDegrees(oldImage: UIImage(named: "car")!, deg: CGFloat(self.bearing))

    return MGLAnnotationImage(image: img, reuseIdentifier: "car")
}
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage
{
    let size = oldImage.size

    UIGraphicsBeginImageContext(size)

    let bitmap: CGContext = UIGraphicsGetCurrentContext()!
    //Move the origin to the middle of the image so we will rotate and scale around the center.
    bitmap.translateBy(x: size.width / 2, y: size.height / 2)
    //Rotate the image context
    bitmap.rotate(by: (degrees * CGFloat(Double.pi / 180)))
    //Now, draw the rotated/scaled image into the context
    bitmap.scaleBy(x: 1.0, y: -1.0)

    let origin = CGPoint(x: -size.width / 2, y: -size.width / 2)

    bitmap.draw(oldImage.cgImage!, in: CGRect(origin: origin, size: size))

    let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return newImage
}

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Best Answer-推荐答案

尝试使用自定义重用标识符，如下所示:

func mapView(_ mapView: MGLMapView, imageFor annotation: MGLAnnotation) -> MGLAnnotationImage? {
    let annotation = annotation as! CustomMapAnnotation

    var annotationImage = mapView.dequeueReusableAnnotationImage(withIdentifier: annotation.id)

    if annotationImage == nil {
        var image = UIImage(named: "taxi")!

        if let heading = annotation.heading {
            image = image.imageRotatedByDegrees(degrees: heading)
        }
        image = image.withAlignmentRectInsets(UIEdgeInsets(top: 0, left: 0, bottom: image.size.height/2, right: 0))

        annotationImage = MGLAnnotationImage(image: image, reuseIdentifier: annotation.id)
    }

    return annotationImage
}

关于ios - 如何在 Mapbox 3.6 中旋转汽车标记图像？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45907301/