piterwilson/framespy

A family of objects that can be used to "spy" on a SwiftUI `View` and collect its `frame` (a `CGRect` describing position and size) relative to a coordinate space.

FrameSpy

A family of objects that can be used to "spy" on a View and collect its frame (a CGRect describing position and size) relative to a coordinate space.

How to use

1. Give a name to your coordinate space using the .coordinateSpace(name:) ViewModifier.

import FrameSpy

struct ContentView: View {
    var body: some View {
        VStack(spacing: 10.0) {
            Text("Text 1")
        }
        .coordinateSpace(name: "ContentView") // the coordinate space is now named "ContentView".
    }
}

2. Declare a "bag" to collect spied frames.

import FrameSpy

struct ContentView: View {
    @State var spiedFrames: SpiedFramesBag = SpiedFramesBag() // spied frames will be collected here.
    var body: some View {
        VStack(spacing: 10.0) {
            Text("Text 1")
        }
        .coordinateSpace(name: "ContentView")
    }
}

3. Spy the Views frame(s) using .spyFrame(named:inCoordinateSpaceNamed:).

import FrameSpy

struct ContentView: View {
    @State var spiedFrames: SpiedFramesBag = SpiedFramesBag()
    var body: some View {
        VStack(spacing: 10.0) {
            Text("Text 1")
               .spyFrame(named: "text-1", inCoordinateSpaceNamed: "ContentView")  // This `Text`s frame is now "spied" in the coordinate space "ContentView". The spied frame's name is "text-1"
        }
        .coordinateSpace(name: "ContentView")
    }
}

4. Collect the spied frame(s) in the bag declared in step 1 using the .collectSpiedFrames(into:) ViewModifier.

import FrameSpy

struct ContentView: View {
    @State var spiedFrames: SpiedFramesBag = SpiedFramesBag()
    var body: some View {
        VStack(spacing: 10.0) {
            Text("Text 1")
                .spyFrame(named: "text-1", inCoordinateSpaceNamed: "ContentView")
        }
        .coordinateSpace(name: "ContentView")
        .collectSpiedFrames(into: $spiedFrames) // The spied frames will be collected into `$spiedFrames`
    }
}

The frame for the Text will be available as spiedFrames["text-1"]. Remember this value is Optional and might not be always available.