Yattee v2 rewrite

Yattee/Extensions/PlatformImage+Cropping.swift

@@ -0,0 +1,61 @@
+//
+//  PlatformImage+Cropping.swift
+//  Yattee
+//
+//  Cross-platform image cropping for extracting thumbnails from sprite sheets.
+//
+
+import Foundation
+import CoreGraphics
+
+#if os(macOS)
+import AppKit
+
+extension NSImage {
+    /// Crops the image to the specified rect.
+    /// - Parameter rect: The rect to crop in image coordinates (origin at top-left)
+    /// - Returns: The cropped image, or nil if cropping fails
+    func cropped(to rect: CGRect) -> NSImage? {
+        // Get CGImage representation
+        guard let cgImage = self.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
+            return nil
+        }
+
+        // NSImage coordinates have origin at bottom-left, but CGImage has origin at top-left
+        // The rect is already in top-left coordinate system, so use it directly
+        guard let croppedCGImage = cgImage.cropping(to: rect) else {
+            return nil
+        }
+
+        return NSImage(cgImage: croppedCGImage, size: rect.size)
+    }
+}
+
+#else
+import UIKit
+
+extension UIImage {
+    /// Crops the image to the specified rect.
+    /// - Parameter rect: The rect to crop in image coordinates (origin at top-left)
+    /// - Returns: The cropped image, or nil if cropping fails
+    func cropped(to rect: CGRect) -> UIImage? {
+        guard let cgImage = self.cgImage else { return nil }
+
+        // Scale rect for image scale (Retina displays)
+        let scale = self.scale
+        let scaledRect = CGRect(
+            x: rect.origin.x * scale,
+            y: rect.origin.y * scale,
+            width: rect.width * scale,
+            height: rect.height * scale
+        )
+
+        guard let croppedCGImage = cgImage.cropping(to: scaledRect) else {
+            return nil
+        }
+
+        return UIImage(cgImage: croppedCGImage, scale: scale, orientation: .up)
+    }
+}
+
+#endif