//
//  ViewController.swift
//  UIGraphicsImageRendererIssue
//
//  Created by Thibault POUJAT on 18/08/2025.
//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // Create a layer filled with a regular UIColor
        let layerWithRegularUIColor = CAShapeLayer()
        layerWithRegularUIColor.frame = CGRect(x: 50, y: 100, width: 100, height: 100)
        layerWithRegularUIColor.path = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 100, height: 100)).cgPath
        layerWithRegularUIColor.fillColor = UIColor.red.cgColor
        view.layer.addSublayer(layerWithRegularUIColor)

        // Create a layer filled with a UIColor(patternImage:)
        let layerWithUIGraphicsImageRendererColor = CAShapeLayer()
        layerWithUIGraphicsImageRendererColor.frame = CGRect(x: 200, y: 100, width: 100, height: 100)
        layerWithUIGraphicsImageRendererColor.path = UIBezierPath(rect: CGRect(x: 0, y: 0, width: 100, height: 100)).cgPath
        layerWithUIGraphicsImageRendererColor.fillColor = UIColor.yellow.patternStripes(color2: UIColor.green).cgColor
        view.layer.addSublayer(layerWithUIGraphicsImageRendererColor)

        view.backgroundColor = UIColor.lightGray

        // Those two layers are displayed correctly on iOS 18.2 and earlier
        // The second one is a pattern color created with UIGraphicsImageRenderer, and is not displayed as expected for iOS 26.0 (23A5318f)
        // Instead of the expected pattern, we get a white/blank rectangle.
    }
}

extension UIColor {
    func patternStripes(color2: UIColor = .clear, barThickness: CGFloat = 5.0) -> UIColor {
        let dim: CGFloat = barThickness * 2.0 * sqrt(2.0)

        let img = UIGraphicsImageRenderer(size: .init(width: dim, height: dim)).image { context in

            // What we do in there does not affect the main issue : we have a blank view with iOS 26

            // rotate the context and shift up
            context.cgContext.rotate(by: CGFloat.pi / 4.0)
            context.cgContext.translateBy(x: 0.0, y: -2.0 * barThickness)

            let bars: [(UIColor, UIBezierPath)] = [
                (self, UIBezierPath(rect: .init(x: -0.0, y: 0.0, width: dim * 2.0, height: barThickness * 1.5))),
                (color2, UIBezierPath(rect: .init(x: -0.0, y: barThickness * 1.5, width: dim * 2.0, height: barThickness * 0.5)))
            ]

            bars.forEach { $0.0.setFill(); $0.1.fill() }

            // move down and paint again
            context.cgContext.translateBy(x: 0.0, y: 2.0 * barThickness)
            bars.forEach { $0.0.setFill(); $0.1.fill() }
        }

        return UIColor(patternImage: img)
    }
}