CODEWITHSUNDEEP
swiftuigraphicscontextmkmapsnapshotter
Anirudha Mahale
Anirudha Mahale

Reputation: 2596

How to set fillColor and strokColor for path in swift

I am getting image of certain area using MKMapSnapshotter.

I draw lines on the image using UIGraphicsGetCurrentContext() to show polygon,

I can set the lines colour but I am unable to set fill color to the polygon.

Below is the code

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!
}

How can I achieve this?

SOLUTION:

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!
}

Upvotes: 1

Views: 1154

Answers (1)

Craig Siemens
Craig Siemens

Reputation: 13296

From the docs for strokePath and fillPath

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

That means that after calling strokePath, the path is cleared so there is noting to draw when you call fillPath

Instead you should call context!.drawPath(using: .fillStroke)

Upvotes: 4

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