Fix converting to color space.

Vernissage.xcodeproj/project.pbxproj

@@ -1059,7 +1059,7 @@
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 41;
+				CURRENT_PROJECT_VERSION = 42;
 				DEVELOPMENT_ASSET_PATHS = "\"Vernissage/Preview Content\"";
 				DEVELOPMENT_TEAM = B2U9FEKYP8;
 				ENABLE_PREVIEWS = YES;
@@ -1096,7 +1096,7 @@
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 41;
+				CURRENT_PROJECT_VERSION = 42;
 				DEVELOPMENT_ASSET_PATHS = "\"Vernissage/Preview Content\"";
 				DEVELOPMENT_TEAM = B2U9FEKYP8;
 				ENABLE_PREVIEWS = YES;

Vernissage/Extensions/UIImage+Size.swift

@@ -6,10 +6,83 @@
     
 import UIKit
 
-extension UIImage {
-    func resized(to size: CGSize) -> UIImage {
-        UIGraphicsImageRenderer(size: size).image { _ in
-            draw(in: CGRect(origin: .zero, size: size))
+extension UIImage.Orientation {
+    var exifOrientation: Int32 {
+        switch self {
+        case .up: return 1
+        case .down: return 3
+        case .left: return 8
+        case .right: return 6
+        case .upMirrored: return 2
+        case .downMirrored: return 4
+        case .leftMirrored: return 5
+        case .rightMirrored: return 7
+        @unknown default: return 1
         }
     }
 }
+
+extension UIImage {
+    func resized(to targetSize: CGSize) -> UIImage {
+        guard let sourceImage = CIImage(image: self, options: [.applyOrientationProperty: true]) else {
+            return self
+        }
+        
+        // We have to store correct image orientation.
+        let orientedImage = sourceImage.oriented(forExifOrientation: self.imageOrientation.exifOrientation)
+        
+        // Filter.
+        let resizeFilter = CIFilter(name:"CILanczosScaleTransform")!
+        
+        // Compute scale.
+        let scale = targetSize.width / orientedImage.extent.width
+
+        // Apply resizing
+        resizeFilter.setValue(orientedImage, forKey: kCIInputImageKey)
+        resizeFilter.setValue(scale, forKey: kCIInputScaleKey)
+        resizeFilter.setValue(1.0, forKey: kCIInputAspectRatioKey)
+
+        guard let result = resizeFilter.value(forKey: kCIOutputImageKey) as? CIImage else {
+            return self
+        }
+
+        guard let resizedCGImage = CIContext(options: nil).createCGImage(result, from: result.extent) else {
+            return self
+        }
+        
+        return UIImage(cgImage: resizedCGImage)
+    }
+    
+    func convertToExtendedSRGBJpeg() -> Data? {
+        guard let sourceImage = CIImage(image: self, options: [.applyOrientationProperty: true]) else {
+            return self.jpegData(compressionQuality: 0.9)
+        }
+        
+        // We have to store correct image orientation.
+        let orientedImage = sourceImage.oriented(forExifOrientation: self.imageOrientation.exifOrientation)
+        
+        // We dont have to convert images which already are in sRGB color space.
+        if orientedImage.colorSpace?.name == CGColorSpace.sRGB || orientedImage.colorSpace?.name == CGColorSpace.extendedSRGB {
+            return self.jpegData(compressionQuality: 0.9)
+        }
+                
+        guard let colorSpace = CGColorSpace(name: CGColorSpace.extendedSRGB) else {
+            return self.jpegData(compressionQuality: 0.9)
+        }
+
+        guard let displayP3 = CGColorSpace(name: CGColorSpace.displayP3) else {
+            return self.jpegData(compressionQuality: 0.9)
+        }
+
+        // Create Core Image context (with working color space).
+        let ciContext = CIContext(options: [CIContextOption.workingColorSpace: orientedImage.colorSpace ?? displayP3])
+        
+        // Creating image with new color space (and preserving colors).
+        guard let converted = ciContext.jpegRepresentation(of: orientedImage, colorSpace: colorSpace) else {
+            return self.jpegData(compressionQuality: 0.9)
+        }
+        
+        // Returning successfully converted image.
+        return converted
+    }
+}

Vernissage/Views/ComposeView/ComposeView.swift

@@ -572,18 +572,26 @@ struct ComposeView: View {
     }
     
     private func getJpegData(image: UIImage) -> Data? {
+#if targetEnvironment(simulator)
+        // For testing purposes.
+        let converted = image.convertToExtendedSRGBJpeg()
+        let filePath = URL.temporaryDirectory.appending(path: "\(UUID().uuidString).jpg")
+        try? converted?.write(to: filePath)
+        print(filePath.string)
+#endif
+        
         // API don't support images over 5K.
         if image.size.height > 10_000 || image.size.width > 10_000 {
             return image
                 .resized(to: .init(width: image.size.width / 4, height: image.size.height / 4))
-                .jpegData(compressionQuality: 0.90)
+                .convertToExtendedSRGBJpeg()
         } else if image.size.height > 5000 || image.size.width > 5000 {
             return image
                 .resized(to: .init(width: image.size.width / 2, height: image.size.height / 2))
-                .jpegData(compressionQuality: 0.90)
+                .convertToExtendedSRGBJpeg()
         } else {
             return image
-                .jpegData(compressionQuality: 0.90)
+                .convertToExtendedSRGBJpeg()
         }
     }