Welcome to issue #31 of the iOS Coffee Break Newsletter 📬.

When I first started posting on Twitter, I wasn't happy with how my newsletter posts displayed, so I built an automated system using SwiftUI and GitHub Actions to generate dynamic preview images for my weekly issues. This approach saves time and ensures each post has a unique, professional look when shared online.

This automated system is out the scope of this week's issue, but if you are curious on how I did it, I recommend checking out the article I wrote on this topic. It walks you through the entire process step by step!

This week, I am diving into the key class that made it all possible 🎉 — ImageRenderer. I will show you how it works and how you can easily integrate it into your apps!

Overview

ImageRenderer is a straightforward tool that can convert a SwiftUI view into various image formats such as CGImage, NSImage or UIImage.

Using it is easy — just create an instance, give it some content and request an image output.

let renderer = ImageRenderer(content: view)
self.image = renderer.uiImage

To see how the renderer works in a working example, here I am creating an image preview for my weekly issues given some properties such as the issue title and number.

@main
struct IssuePreview: AsyncParsableCommand {
    [...]
 
    @MainActor mutating func run() async throws {
        [...]
 
        let view = IssueView(
            colors: colors,
            foregroundColor: foreground,
            title: issue.title,
            date: date,
            issueNumber: issue.number
        )
        .frame(width: 1280, height: 640)
 
        guard let image = ImageRenderer(content: view).nsImage else { throw Error.invalidImageData }
        guard let imageData = image.asPNGData else { throw Error.imageCreationFailed }
 
        let folderURL = URL(fileURLWithPath: "issues")
        let fileURL = folderURL.appendingPathComponent("\(issue.number).png")
        try imageData.write(to: fileURL)
    }
}

The Output

Although I am (still considering) to make some adjustments and improvements, here is what I have got so far:

iOS Coffee Break Newsletter issue #15 with custom preview image!

CURATED FROM THE COMMUNITY

🍎📱💻 Multiplatform Development for Apple Devices

Are you working to make your app run across multiple Apple platforms?

In his first blog post of 2025, Darryl walks through the process of bringing his side project to the Vision Pro. If you are working on making your own apps compatible with new Apple devices, this is definitely worth a read!

🦺 Container relative frames in SwiftUI

If you have encountered performance issues from overusing GeometryReader in your SwiftUI apps, you might want to check out Majid's article!

He explains how to use the containerRelativeFrame view modifier, which allows you to define a view’s size relative to its parent without relying on GeometryReader. This can help simplify your layouts and improve performance.

🎙️ Dev Conversations #6: Krzysztof Zabłocki

Dev Conversations is a monthly series where Swift Toolkit features people who contribute to the Swift community!

In episode #6, Natan interviews Krzysztof, the creator of Sourcery, to discuss his career, open-source contributions, and his decision to leave a full-time job to become independent. It is a great talk that might just inspire you to go full indie 🚀!