SwiftUI - Add Border to One Edge of an Image

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说谎
说谎 2021-02-04 09:07

It\'s a pretty straight-forward question - how does one apply a border effect to only the wanted edges of an Image with SwiftUI?

For example, I only want to apply a borde

3条回答
  •  陌清茗
    陌清茗 (楼主)
    2021-02-04 09:49

    Demo


    Implementation

    You can use this modifier on any View:

    .border(width: 5, edges: [.top, .leading], color: .yellow)
    

    With the help of this simple extension:

    extension View {
        func border(width: CGFloat, edges: [Edge], color: Color) -> some View {
            overlay(EdgeBorder(width: width, edges: edges).foregroundColor(color))
        }
    }
    

    And here is the magic struct behind this:

    struct EdgeBorder: Shape {
    
        var width: CGFloat
        var edges: [Edge]
    
        func path(in rect: CGRect) -> Path {
            var path = Path()
            for edge in edges {
                var x: CGFloat {
                    switch edge {
                    case .top, .bottom, .leading: return rect.minX
                    case .trailing: return rect.maxX - width
                    }
                }
    
                var y: CGFloat {
                    switch edge {
                    case .top, .leading, .trailing: return rect.minY
                    case .bottom: return rect.maxY - width
                    }
                }
    
                var w: CGFloat {
                    switch edge {
                    case .top, .bottom: return rect.width
                    case .leading, .trailing: return self.width
                    }
                }
    
                var h: CGFloat {
                    switch edge {
                    case .top, .bottom: return self.width
                    case .leading, .trailing: return rect.height
                    }
                }
                path.addPath(Path(CGRect(x: x, y: y, width: w, height: h)))
            }
            return path
        }
    }
    

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