Crop Rectangle view with shape SwiftUI

Question

I am trying to make the center portion of the view transparent like a camera overlay. As shown in the below picture where the center portion is transparent while the remaining area is black colored with opacity.

I tried the below code.

Rectangle()
    .fill(Color.red.opacity(0.5))
    .mask(
        Ellipse()
            .fill(
                Color.green.opacity(0.5)
            )
            .padding()
    )
}

but the output is this.

Any help will be appreciated.

Thanks

Check this out: https://stackoverflow.com/a/59659733/14351818 — aheze, May 01 '21 at 05:06

score 5 · Accepted Answer · answered May 01 '21 at 05:06

This is adapted from @Asperi's answer here: https://stackoverflow.com/a/59659733/560942

struct MaskShape : Shape {
    var inset : UIEdgeInsets
    
    func path(in rect: CGRect) -> Path {
        var shape = Rectangle().path(in: rect)
        shape.addPath(Ellipse().path(in: rect.inset(by: inset)))
        return shape
    }
}

struct ContentView : View {

    var body: some View {
        ZStack {
            Image("2")
                .resizable()
                .aspectRatio(contentMode: .fill)
            GeometryReader { geometry in
                Color.black.opacity(0.6)
                .mask(
                    MaskShape(
                        inset: UIEdgeInsets(top: geometry.size.height / 6,
                                          left: geometry.size.width / 6,
                                          bottom: geometry.size.height / 6,
                                          right: geometry.size.width / 6)
                    ).fill(style: FillStyle(eoFill: true))
                )
            }
        }
    }
}

The ZStack sets up the image and then a semi-transparent black overlay on the top. The overlay is cut away with a mask with eoFill set to true. I added some code to provide insets for the mask, as I'm assuming this might be a variably-sized mask.

Lots of minutiae that can be changed (like the image aspect ratio, the insets, etc), but it should get you started.

Crop Rectangle view with shape SwiftUI

1 Answers1