Add image adapters and tests

Sources/GoogleAI/PartsRepresentable.swift

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import Foundation
+import UniformTypeIdentifiers
 #if canImport(UIKit)
   import UIKit // For UIImage extensions.
 #elseif canImport(AppKit)
@@ -77,3 +78,42 @@ extension [any PartsRepresentable]: PartsRepresentable {
     }
   }
 #endif
+
+extension CGImage: PartsRepresentable {
+  public var partsValue: [ModelContent.Part] {
+    let output = NSMutableData()
+    guard let imageDestination = CGImageDestinationCreateWithData(
+      output, UTType.jpeg.identifier as CFString, 1, nil
+    ) else {
+      Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CGImage.")
+      return []
+    }
+    CGImageDestinationAddImage(imageDestination, self, nil)
+    CGImageDestinationSetProperties(imageDestination, [
+      kCGImageDestinationLossyCompressionQuality: 0.8,
+    ] as CFDictionary)
+    if CGImageDestinationFinalize(imageDestination) {
+      return [.data(mimetype: "image/jpeg", output as Data)]
+    }
+    Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CGImage.")
+    return []
+  }
+}
+
+extension CIImage: PartsRepresentable {
+  public var partsValue: [ModelContent.Part] {
+    let context = CIContext()
+    let jpegData = (colorSpace ?? CGColorSpace(name: CGColorSpace.sRGB))
+      .flatMap {
+        // The docs specify kCGImageDestinationLossyCompressionQuality as a supported option, but
+        // Swift's type system does not allow this.
+        // [kCGImageDestinationLossyCompressionQuality: 0.8]
+        context.jpegRepresentation(of: self, colorSpace: $0, options: [:])
+      }
+    if let jpegData = jpegData {
+      return [.data(mimetype: "image/jpeg", jpegData)]
+    }
+    Logging.default.error("[GoogleGenerativeAI] Couldn't create JPEG from CIImage.")
+    return []
+  }
+}

Tests/GoogleAITests/PartsRepresentableTests.swift

@@ -0,0 +1,53 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import XCTest
+
+final class PartsRepresentableTests: XCTestCase {
+  let imageURL = Bundle.main.url(forResource: "logo", withExtension: "png")!
+
+  func testModelContentFromCGImageIsNotEmpty() throws {
+    guard let dataProvider = CGDataProvider(url: imageURL as CFURL) else {
+      XCTFail("Could not find data for url: \(imageURL)")
+      return
+    }
+    guard let image = CGImage(pngDataProviderSource: dataProvider,
+                              decode: nil,
+                              shouldInterpolate: false,
+                              intent: .defaultIntent) else {
+      XCTFail("Could not construct CGImage from URL: \(imageURL)")
+      return
+    }
+    let modelContent = image.partsValue
+    XCTAssert(modelContent.count > 0, "Expected non-empty model content for CGImage: \(image)")
+  }
+
+  func testModelContentFromCIImageIsNotEmpty() throws {
+    guard let image = CIImage(contentsOf: imageURL) else {
+      XCTFail("Could not construct CIImage from URL: \(imageURL)")
+      return
+    }
+    let modelContent = image.partsValue
+    XCTAssert(modelContent.count > 0, "Expected non-empty model content for CGImage: \(image)")
+  }
+
+  func testModelContentFromUIImageIsNotEmpty() throws {
+    guard let image = UIImage(named: "logo.png") else {
+      XCTFail("Could not find image named logo.png.")
+      return
+    }
+    let modelContent = image.partsValue
+    XCTAssert(modelContent.count > 0, "Expected non-empty model content for UIImage: \(image)")
+  }
+}