如何在 swift 中为路径设置 fillColor 和 strokColor

Question

我正在使用 MKMapSnapshotter 获取特定区域的图像。

我使用 UIGraphicsGetCurrentContext() 在图像上绘制线条以显示多边形，

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: [=12=])) }

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

    let resultImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return resultImage!
}

Answer 1

来自 strokePath 和 fillPath

的文档

The current path is cleared as a side effect of calling this function.

意思是调用strokePath后，路径被清空，所以调用fillPath时没有注意绘制

你应该调用 context!.drawPath(using: .fillStroke)

如何在 swift 中为路径设置 fillColor 和 strokColor

How to set fillColor and strokColor for path in swift

uigraphicscontext

mkmapsnapshotter

swift