Crash when wrapping items to try the package.

[matthewkrom]

Interesting library! On my first attempt, wrapping three GroupBoxes that dynamically appear on model load, I saw

Thread 1: Fatal error: view origin is invalid: (407.25, nan), UnitPoint(x: 0.0, y: 0.0), (297.5, inf)

Apologies, I may not spend a lot of time debugging this, but I hope this stack trace and error report might be useful.

Text version, with ** starred line:

    private func alignAndPlace(
        _ item: Line.Element,
        in line: Lines.Element,
        at target: Size
    ) {
        var position = target
        let lineDepth = line.size.depth
        let size = Size(breadth: item.size.breadth, depth: lineDepth)
        let proposedSize = ProposedViewSize(size: size, axis: axis)
        let itemDepth = item.size.depth
        if itemDepth > 0 {
            let dimensions = item.item.subview.dimensions(proposedSize)
            let alignedPosition = alignmentOnDepth(dimensions)
            position.depth += (alignedPosition / itemDepth) * (lineDepth - itemDepth)
        }
        let point = CGPoint(size: position, axis: axis)
**        item.item.subview.place(at: point, anchor: .topLeading, proposal: proposedSize)
    }

Stack trace:

[tevelee]

Thank you for reporting! Do you have some example code of the callsite where you've used the GroupBoxes inside HFlow? That would be really helpful for me to diagnose what causes the nan value?

[matthewkrom]

Thanks! OK, I have one, and I'm cleaning it up and will submit. It'll be a single SwiftUI View — shall I email it to you, or attach to Github? Thx, Matt

…

On Mon, Jan 20, 2025 at 10:06 AM Laszlo Teveli ***@***.***> wrote: Thank you for reporting! Do you have some example code of the callsite where you've used the GroupBoxes inside HFlow? That would be really helpful for me to diagnose what causes the nan value? — Reply to this email directly, view it on GitHub <#24 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADALEYYHIKENNMAXWFO62D2LUGHZAVCNFSM6AAAAABVML6RPKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDMMBSGY2TQMRQHE> . You are receiving this because you authored the thread.Message ID: ***@***.***>

-- Matthew Krom MW Krom LLC / Web+mobile product design, development, engineering, experience Cambridge, MA USA Tel/Text +1 617 852 5130 http://www.mwkrom.com

[matthewkrom]

Here you are! When I initially reported it, I wasn't sure if I was invested enough to create an isolated example. But since you wrote back right away, I went for it. I'm sure this could be simplified even more and still illustrate the problem, but I'm equally sure this is a terrific starting point for you to pinpoint the issue.

//
//  ContentView.swift
//  SwiftUIFlowTester
//
//  Created by Matthew Krom on 1/20/25.
//

import SwiftUI
import Flow

struct ContentView: View {
  
  var body: some View {
    
    VStack {
      Text("Flow Testing")
        .font(.title)
      HFlow(alignment: .top) {
        GroupBox {
          Text("A")
        }
        GroupBox {
          Text("B")
          
        }
        GroupBox {
          Text("C")
          Text("...")
          Text("...")
          Text("...")
          Text("...")
          Text("...")
        }
        /* The reason we have multiple frame/fixedSize here is that in the real
         project, there are subviews (container views) which provide these
         .frame modifiers — we don't have them all in one place, if you see what I mean. */
        .frame(
          maxWidth: .infinity,
          maxHeight: .infinity,
          alignment: .topLeading
        )
        .padding(.bottom)
        .padding(.horizontal)
        .fixedSize(horizontal: true, vertical: false)
      }
    }
    .frame(maxWidth: .infinity)
  }
}

#Preview {
  ContentView()
}

[tevelee]

Much appreciated! I can fix it now using this example

[tevelee]

Please check out version 3.0.1 whether your crash has been resolved.

The setting .frame(maxHeight: .infinity) can cause the view to be distorted, but at least it won't crash now.

[matthewkrom]

Thank you! That did (of course) fix the crash!

In the process of trying again in my large project, I developed another crash test case, which I'll post as a separate issue for you.