A SwiftUI view modifier to limit the content size category of a view to a specified maximum size.

ContentSizeCategoryModifier.swift

import SwiftUI

fileprivate struct ContentSizeCategoryModifier: ViewModifier {
    
    // MARK:- Properties
    
    /// The preferred size of the content.
    @Environment(\.sizeCategory) private var sizeCategory
    
    /// The maximum permitted content size category.
    let sizeCategoryLimit: ContentSizeCategory
    
    // MARK:- Methods
    
    func body(content: Content) -> some View {
        content.environment(\.sizeCategory, sizeCategory > sizeCategoryLimit ? sizeCategoryLimit : sizeCategory)
    }
    
}

extension View {
    
    /// Limits the content size category of the view to the specified value.
    ///
    /// - Parameters:
    ///   - sizeCategoryLimit: The maximum permitted content size category.
    func contentSizeCategoryLimited(to sizeCategoryLimit: ContentSizeCategory) -> some View {
        modifier(ContentSizeCategoryModifier(sizeCategoryLimit: sizeCategoryLimit))
    }
    
}