0

我正在使用MKMapSnapshotter.

我在图像上画线UIGraphicsGetCurrentContext()用于显示多边形，

我可以设置线条颜色，但无法为多边形设置填充颜色。

下面是代码

private func drawLineOnImage(snapshot: MKMapSnapshotter.Snapshot, coordinates: [CLLocationCoordinate2D]) -> UIImage {
    let image = snapshot.image

    UIGraphicsBeginImageContextWithOptions(getMapFrameSize(), true, 0)

    image.draw(at: CGPoint.zero)

    let context = UIGraphicsGetCurrentContext()
    context!.setLineWidth(2.0)
    context!.setStrokeColor(UIColor.red.cgColor)
    context!.move(to: snapshot.point(for: coordinates[0]))
    for i in 0...coordinates.count-1 {
        context!.addLine(to: snapshot.point(for: coordinates[i]))
        context!.move(to: snapshot.point(for: coordinates[i]))
    }
    context!.strokePath()
    context!.setFillColor(UIColor.green.cgColor)
    context!.fillPath()

    let resultImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return resultImage!
}

我怎样才能做到这一点？

解决方案：

private func drawLineOnImage(snapshot: MKMapSnapshotter.Snapshot, coordinates: [CLLocationCoordinate2D]) -> UIImage {
    let image = snapshot.image

    UIGraphicsBeginImageContextWithOptions(getMapFrameSize(), true, 0)

    image.draw(at: CGPoint.zero)

    let context = UIGraphicsGetCurrentContext()!

    context.setLineWidth(2.0)
    context.setStrokeColor(annotationColor.cgColor)
    context.setFillColor(annotationColor.withAlphaComponent(0.5).cgColor)

    var coordinates = coordinates
    if let firstPoint = coordinates.first { context.move(to: snapshot.point(for: firstPoint)) }
    context.move(to: snapshot.point(for: coordinates[0]))
    coordinates.removeFirst()
    coordinates.forEach { context.addLine(to: snapshot.point(for: $0)) }

    context.drawPath(using: .fillStroke)
    context.fillPath()

    let resultImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return resultImage!
}
4

1 回答 1

3

strokePath来自和的文档fillPath

调用此函数的副作用是清除当前路径。

这意味着在调用之后strokePath，路径会被清除，所以当你调用时就不会注意到要绘制fillPath

相反，你应该打电话context!.drawPath(using: .fillStroke)

于 2019-06-20T19:18:55.843 回答