Merge pull request #23 from MohammadRezaAnsari/imageOrientation

Add fixedOrientationToUp for UIImage

Sources/ExtensionKit/UIExtensions/UIImage/UIImage+Orientation.swift

@@ -0,0 +1,75 @@
+//
+//  UIImage+Orientation.swift
+//  
+//
+//  Created by Mahshid Sharif on 12/22/21.
+//
+
+import UIKit
+
+extension UIImage {
+
+    func fixedOrientationToUp() -> UIImage? {
+
+        guard imageOrientation != UIImage.Orientation.up else {
+            // This is default orientation, don't need to do anything
+            return self.copy() as? UIImage
+        }
+
+        guard let cgImage = self.cgImage else {
+            // CGImage is not available
+            return nil
+        }
+
+        guard let colorSpace = cgImage.colorSpace, let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: cgImage.bitsPerComponent, bytesPerRow: 0, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
+            return nil // Not able to create CGContext
+        }
+
+        var transform: CGAffineTransform = CGAffineTransform.identity
+
+        switch imageOrientation {
+        case .down, .downMirrored:
+            transform = transform.translatedBy(x: size.width, y: size.height)
+            transform = transform.rotated(by: CGFloat.pi)
+        case .left, .leftMirrored:
+            transform = transform.translatedBy(x: size.width, y: 0)
+            transform = transform.rotated(by: CGFloat.pi / 2.0)
+        case .right, .rightMirrored:
+            transform = transform.translatedBy(x: 0, y: size.height)
+            transform = transform.rotated(by: CGFloat.pi / -2.0)
+        case .up, .upMirrored:
+            break
+        @unknown default:
+            fatalError("Missing...")
+            break
+        }
+
+        // Flip image one more time if needed to, this is to prevent flipped image
+        switch imageOrientation {
+        case .upMirrored, .downMirrored:
+            transform = transform.translatedBy(x: size.width, y: 0)
+            transform = transform.scaledBy(x: -1, y: 1)
+        case .leftMirrored, .rightMirrored:
+            transform = transform.translatedBy(x: size.height, y: 0)
+            transform = transform.scaledBy(x: -1, y: 1)
+        case .up, .down, .left, .right:
+            break
+        @unknown default:
+            fatalError("Missing...")
+            break
+        }
+
+        ctx.concatenate(transform)
+
+        switch imageOrientation {
+        case .left, .leftMirrored, .right, .rightMirrored:
+            ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
+        default:
+            ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
+            break
+        }
+
+        guard let newCGImage = ctx.makeImage() else { return nil }
+        return UIImage.init(cgImage: newCGImage, scale: 1, orientation: .up)
+    }
+}