Rotate image

2 files changed, 70 insertions, 4 deletions

diff --git a/Sources/SwiftyCrop/Models/CropViewModel.swift b/Sources/SwiftyCrop/Models/CropViewModel.swift
index a9557ac..9d5e16d 100644
--- a/Sources/SwiftyCrop/Models/CropViewModel.swift
+++ b/Sources/SwiftyCrop/Models/CropViewModel.swift
@@ -123,6 +123,47 @@ class CropViewModel: ObservableObject {
     }
 
     /**
+     Rotates the image to the angle that is rotated inside the view.
+     - Parameters:
+        - image: The UIImage to rotate
+        - angle: The Angle to rotate to
+     - Returns: A rotated UIImage if the rotating operation is successful; otherwise nil.
+     */
+    func rotate(_ image: UIImage, _ angle: Angle) -> UIImage? {
+        guard let orientedImage = image.correctlyOriented else {
+            return nil
+        }
+
+        guard let cgImage = orientedImage.cgImage else {
+            return nil
+        }
+
+        let ciImage = CIImage(cgImage: cgImage)
+
+        // Prepare filter
+        let filter = CIFilter.straightenFilter(
+            image: ciImage,
+            radians: angle.radians
+        )
+
+        // Get output image
+        guard let output = filter?.outputImage else {
+            return nil
+        }
+
+        // Create resulting image
+        let context = CIContext()
+        guard let result = context.createCGImage(
+            output,
+            from: output.extent
+        ) else {
+            return nil
+        }
+
+        return UIImage(cgImage: result)
+    }
+
+    /**
      Calculates the rectangle to crop.
      - Parameters:
         - image: The UIImage to calculate the rectangle to crop for
@@ -178,3 +219,23 @@ private extension UIImage {
         return normalizedImage
     }
 }
+
+private extension CIFilter {
+    /**
+     Creates the straighten filter.
+     - Parameters:
+        - inputImage: The CIImage to use as an input image
+        - radians: An angle in radians
+     - Returns: A generated CIFilter.
+     */
+    static func straightenFilter(image: CIImage, radians: Double) -> CIFilter? {
+        let angle: Double = radians != 0 ? -radians : 0
+        guard let filter = CIFilter(name: "CIStraightenFilter") else {
+            return nil
+        }
+        filter.setDefaults()
+        filter.setValue(image, forKey: kCIInputImageKey)
+        filter.setValue(angle, forKey: kCIInputAngleKey)
+        return filter
+    }
+}
diff --git a/Sources/SwiftyCrop/View/CropView.swift b/Sources/SwiftyCrop/View/CropView.swift
index c76f7f8..9619efb 100644
--- a/Sources/SwiftyCrop/View/CropView.swift
+++ b/Sources/SwiftyCrop/View/CropView.swift
@@ -64,7 +64,7 @@ struct CropView: View {
             .onEnded { _ in
                 viewModel.lastOffset = viewModel.offset
             }
-        
+
         let rotationGesture = RotationGesture()
             .onChanged { value in
                 viewModel.angle = value
@@ -138,10 +138,15 @@ struct CropView: View {
     }
 
     private func cropImage() -> UIImage? {
-        if maskShape == .circle && configuration.cropImageCircular {
-            return viewModel.cropToCircle(image)
+        if let rotatedImage: UIImage = viewModel.rotate(image, viewModel.lastAngle) {
+            if maskShape == .circle && configuration.cropImageCircular {
+                return viewModel.cropToCircle(rotatedImage)
+            } else {
+                return viewModel.cropToSquare(rotatedImage)
+            }
+            return rotatedImage
         } else {
-            return viewModel.cropToSquare(image)
+            return nil
         }
     }