Creating Thumbnail Images in Swift using UIKit

#swift #ios #uikit #development

📱 Creating Thumbnail Images in Swift using UIKit

Creating thumbnail images is a great way to improve performance in iOS apps—especially when you're working with UITableView or UICollectionView. This post shows how to generate a resized and compressed version of a UIImage using UIKit.

✂️ Why Use Thumbnail Images?

Performance: Smaller images load faster and reduce memory usage.
User Experience: Helps keep your UI smooth and responsive.
Storage: Reduces app size and bandwidth when uploading/downloading images.

🛠 The Code

Here's a simple function to create a thumbnail from a UIImage while preserving its aspect ratio and compressing the result:


swift
import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var tableView: UITableView!

    func createThumbnailImage(image: UIImage, size: CGSize) -> UIImage? {
        let scale = max(size.width/image.size.width, size.height/image.size.height)
        let width = image.size.width * scale
        let height = image.size.height * scale
        let newSize = CGSize(width: width, height: height)
        UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
        image.draw(in: CGRect(origin: CGPoint.zero, size: newSize))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        if let jpegData = newImage?.jpegData(compressionQuality: 0.8) {
            return UIImage(data: jpegData)
        } else {
            return nil
        }
    }
}

DEV Community

Creating Thumbnail Images in Swift using UIKit

📱 Creating Thumbnail Images in Swift using UIKit

✂️ Why Use Thumbnail Images?

🛠 The Code

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