Migrate UIImage APIs to using UIImageAsset on iOS13 (#82)

* Mark DMTraitCollection.current as deprecated

* System built-in support for dark/light mode UIImage

FluentDarkModeKit.xcodeproj/project.pbxproj

@@ -55,6 +55,7 @@
 		8CE066D0239E5586002CE16D /* UIImage+DarkModeKit.m in Sources */ = {isa = PBXBuildFile; fileRef = 8CC8D8722398E7A30043276A /* UIImage+DarkModeKit.m */; };
 		EA2EA50024A1CBF2001AE312 /* SceneDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA2EA4FE24A1CAD5001AE312 /* SceneDelegate.swift */; };
 		EA7316F1248F5055009AE037 /* UILabelVC.swift in Sources */ = {isa = PBXBuildFile; fileRef = EA7316EF248F5050009AE037 /* UILabelVC.swift */; };
+		EAE6065624A9DA1B001304D1 /* UIImageViewVC.swift in Sources */ = {isa = PBXBuildFile; fileRef = EAE6065324A9D9E0001304D1 /* UIImageViewVC.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -149,6 +150,7 @@
 		8CDA628B2366DAA9004895B5 /* DMDynamicColor.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DMDynamicColor.h; sourceTree = "<group>"; };
 		EA2EA4FE24A1CAD5001AE312 /* SceneDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneDelegate.swift; sourceTree = "<group>"; };
 		EA7316EF248F5050009AE037 /* UILabelVC.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = UILabelVC.swift; sourceTree = "<group>"; };
+		EAE6065324A9D9E0001304D1 /* UIImageViewVC.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UIImageViewVC.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -289,6 +291,7 @@
 				8C63F64123A36B0900D93CF4 /* UIButtonVC.swift */,
 				8C63F64423A374CF00D93CF4 /* UIPageControlVC.swift */,
 				EA7316EF248F5050009AE037 /* UILabelVC.swift */,
+				EAE6065324A9D9E0001304D1 /* UIImageViewVC.swift */,
 				8CAFD9DD23715FAB001A63B8 /* Assets.xcassets */,
 				8CAFD9DF23715FAB001A63B8 /* LaunchScreen.storyboard */,
 				8CAFD9E223715FAB001A63B8 /* Info.plist */,
@@ -576,6 +579,7 @@
 				8C7B250C23A22A80002E2558 /* UIActivityIndicatorViewVC.swift in Sources */,
 				8CAFD9D923715FAA001A63B8 /* ViewController.swift in Sources */,
 				8C63F64323A36B2700D93CF4 /* UIButtonVC.swift in Sources */,
+				EAE6065624A9DA1B001304D1 /* UIImageViewVC.swift in Sources */,
 				EA7316F1248F5055009AE037 /* UILabelVC.swift in Sources */,
 				8CAFD9ED2371606D001A63B8 /* NavigationController.swift in Sources */,
 				EA2EA50024A1CBF2001AE312 /* SceneDelegate.swift in Sources */,

Sources/DarkModeCore/DMDynamicColor.m

@@ -22,7 +22,7 @@
 }
 
 - (UIColor *)resolvedColor {
-  return [self resolvedColorWithTraitCollection:DMTraitCollection.currentTraitCollection];
+  return [self resolvedColorWithTraitCollection:DMTraitCollection.overrideTraitCollection];
 }
 
 - (UIColor *)resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {

Sources/DarkModeCore/DMDynamicImage.m

@@ -37,7 +37,7 @@
 }
 
 - (UIImage *)resolvedImage {
-  if (DMTraitCollection.currentTraitCollection.userInterfaceStyle == DMUserInterfaceStyleDark) {
+  if (DMTraitCollection.overrideTraitCollection.userInterfaceStyle == DMUserInterfaceStyleDark) {
     return self.darkImage;
   } else {
     return self.lightImage;

Sources/DarkModeCore/DMTraitCollection.h

@@ -17,7 +17,7 @@ typedef NS_ENUM(NSInteger, DMUserInterfaceStyle) {
 
 @interface DMTraitCollection : NSObject
 
-@property (class, nonatomic, readonly) DMTraitCollection *currentTraitCollection;
+@property (class, nonatomic, readonly) DMTraitCollection *currentTraitCollection API_DEPRECATED("Use overrideTraitCollection instead.", ios(11.0, 11.0));
 @property (class, nonatomic, readonly) DMTraitCollection *overrideTraitCollection;
 
 + (DMTraitCollection *)traitCollectionWithUserInterfaceStyle:(DMUserInterfaceStyle)userInterfaceStyle;

Sources/DarkModeCore/DMTraitCollection.m

@@ -45,7 +45,7 @@
 
 @implementation DMTraitCollection
 
-static DMTraitCollection *_overrideTraitCollection = nil; // This is set manually in setCurrentTraitCollection:animated
+static DMTraitCollection *_overrideTraitCollection = nil; // This is set manually in setOverrideTraitCollection:animated
 static void (^_userInterfaceStyleChangeHandler)(DMTraitCollection *, BOOL) = nil;
 static BOOL _isObservingNewWindowAddNotification = NO;
 
@@ -68,8 +68,8 @@ static BOOL _isObservingNewWindowAddNotification = NO;
   return [DMTraitCollection traitCollectionWithUITraitCollection:UIScreen.mainScreen.traitCollection];
 }
 
-+ (void)setOverrideTraitCollection:(DMTraitCollection *)currentTraitCollection animated:(BOOL)animated {
-  _overrideTraitCollection = currentTraitCollection;
++ (void)setOverrideTraitCollection:(DMTraitCollection *)overrideTraitCollection animated:(BOOL)animated {
+  _overrideTraitCollection = overrideTraitCollection;
   [self syncImmediatelyAnimated:animated];
 }
 

Sources/DarkModeCore/UIImage+DarkModeKit.m

@@ -5,6 +5,7 @@
 
 #import "UIImage+DarkModeKit.h"
 #import "DMDynamicImage.h"
+#import "DMTraitCollection.h"
 
 @import ObjectiveC;
 
@@ -36,6 +37,22 @@
 }
 
 + (UIImage *)dm_imageWithLightImage:(UIImage *)lightImage darkImage:(UIImage *)darkImage {
+  if (@available(iOS 13, *)) {
+    UIImageAsset *imageAsset = [[UIImageAsset alloc] init];
+
+    // Always specify a displayScale otherwise a default of 1.0 is assigned
+    [imageAsset registerImage:lightImage withTraitCollection:[UITraitCollection traitCollectionWithTraitsFromCollections:@[
+      [UITraitCollection traitCollectionWithUserInterfaceStyle:UIUserInterfaceStyleLight],
+      [UITraitCollection traitCollectionWithDisplayScale:lightImage.scale]
+    ]]];
+    [imageAsset registerImage:darkImage withTraitCollection:[UITraitCollection traitCollectionWithTraitsFromCollections:@[
+      [UITraitCollection traitCollectionWithUserInterfaceStyle:UIUserInterfaceStyleDark],
+      [UITraitCollection traitCollectionWithDisplayScale:darkImage.scale]
+    ]]];
+
+    return [imageAsset imageWithTraitCollection:DMTraitCollection.overrideTraitCollection.uiTraitCollection];
+  }
+
   return (UIImage *)[[DMDynamicImageProxy alloc] initWithLightImage:lightImage darkImage:darkImage];
 }
 

Sources/FluentDarkModeKit/Extensions/UILabel+DarkModeKit.swift

@@ -19,8 +19,8 @@ extension UILabel {
     class_replaceMethod(UILabel.self, selector, imp_implementationWithBlock({ (self: UILabel) -> Void in
         let oldIMP = unsafeBitCast(imp, to: (@convention(c) (UILabel, Selector) -> Void).self)
         oldIMP(self, selector)
-        if self.currentUserInterfaceStyle != DMTraitCollection.current.userInterfaceStyle {
-          self.currentUserInterfaceStyle = DMTraitCollection.current.userInterfaceStyle
+        if self.currentUserInterfaceStyle != DMTraitCollection.override.userInterfaceStyle {
+          self.currentUserInterfaceStyle = DMTraitCollection.override.userInterfaceStyle
           self.dmTraitCollectionDidChange(nil)
         }
       } as @convention(block) (UILabel) -> Void), method_getTypeEncoding(method))

Sources/FluentDarkModeKit/Extensions/UIScrollView+DarkModeKit.swift

@@ -14,7 +14,7 @@ extension UIScrollView {
     dm_updateDynamicColors()
 
     indicatorStyle = {
-      if DMTraitCollection.current.userInterfaceStyle == .dark {
+      if DMTraitCollection.override.userInterfaceStyle == .dark {
         return .white
       }
       else {

Sources/FluentDarkModeKit/Extensions/UITextField+DarkModeKit.swift

@@ -18,7 +18,7 @@ extension UITextField {
     }
 
     keyboardAppearance = {
-      if DMTraitCollection.current.userInterfaceStyle == .dark {
+      if DMTraitCollection.override.userInterfaceStyle == .dark {
         return .dark
       }
       else {

Sources/FluentDarkModeKit/Extensions/UITextView+DarkModeKit.swift

@@ -14,7 +14,7 @@ extension UITextView {
     dm_updateDynamicColors()
 
     keyboardAppearance = {
-      if DMTraitCollection.current.userInterfaceStyle == .dark {
+      if DMTraitCollection.override.userInterfaceStyle == .dark {
         return .dark
       }
       else {

Sources/FluentDarkModeKitExample/MainViewController.swift

@@ -18,7 +18,8 @@ final class MainViewController: ViewController {
     Row(name: "UIActivityIndicatorView", vcType: UIActivityIndicatorViewVC.self),
     Row(name: "UIButton", vcType: UIButtonVC.self),
     Row(name: "UILabel", vcType: UILabelVC.self),
-    Row(name: "UIPageControl", vcType: UIPageControlVC.self)
+    Row(name: "UIPageControl", vcType: UIPageControlVC.self),
+    Row(name: "UIImageView", vcType: UIImageViewVC.self),
   ]
 
   lazy var tableView: UITableView = {

Sources/FluentDarkModeKitExample/UIImageViewVC.swift

@@ -0,0 +1,39 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License.
+//
+
+import FluentDarkModeKit
+
+private extension UIColor {
+  var demoImage: UIImage {
+    let size = CGSize(width: 50, height: 50)
+    return UIGraphicsImageRenderer(size: size).image { context in
+      setFill()
+      context.fill(CGRect(origin: .zero, size: size))
+    }
+  }
+}
+
+final class UIImageViewVC: ViewController {
+  let imageView: UIImageView = {
+    let imageView = UIImageView()
+    imageView.image = UIImage(.dm, light: UIColor.red.demoImage, dark: UIColor.green.demoImage)
+    return imageView
+  }()
+
+  override func viewDidLoad() {
+    super.viewDidLoad()
+
+    view.backgroundColor = UIColor(.dm, light: .white, dark: .black)
+
+    view.addSubview(imageView)
+  }
+
+  override func viewDidLayoutSubviews() {
+    super.viewDidLayoutSubviews()
+
+    imageView.sizeToFit()
+    imageView.center = view.center
+  }
+}

Tests/FluentDarkModeKitUITests/DarkModeKitUITests.swift

@@ -32,9 +32,21 @@ final class DarkModeKitUITests: XCTestCase {
     _test("UIPageControl")
   }
 
+  func testUILabel() {
+    _test("UILabel")
+  }
+
+  func testUIImageView() {
+    _test("UIImageView")
+  }
+
   func _test(_ className: String) {
     let app = XCUIApplication()
-    let refreshButton = app.navigationBars["FluentDarkModeKitExample.MainView"].buttons["Refresh"]
+    let navigationBarIdentifier = "0" // Current window index is used as navigation bar title
+    let refreshButtonIdentifier = "Refresh"
+    let compareNavigatonBarTitle = "FluentDarkModeKitExample.View"
+
+    let refreshButton = app.navigationBars[navigationBarIdentifier].buttons[refreshButtonIdentifier]
     refreshButton.tap() // light mode
     refreshButton.tap() // dark mode
 
@@ -45,14 +57,15 @@ final class DarkModeKitUITests: XCTestCase {
 
     let screenshot1 = app.screenshot()
 
-    app.navigationBars["FluentDarkModeKitExample.\(className)VC"].buttons["Back"].tap()
+    let backButtonTitle = navigationBarIdentifier
+    app.navigationBars[navigationBarIdentifier].buttons[backButtonTitle].tap()
     refreshButton.tap() // unspecified
     refreshButton.tap() // light mode
     uiviewStaticText.tap()
 
     let tabBarsQuery = app.tabBars
     tabBarsQuery.children(matching: .button).element(boundBy: 1).tap()
-    app.navigationBars["FluentDarkModeKitExample.View"].buttons["Refresh"].tap()
+    app.navigationBars[compareNavigatonBarTitle].buttons[refreshButtonIdentifier].tap()
     tabBarsQuery.children(matching: .button).element(boundBy: 0).tap() // dark mode
 
     let screenshot2 = app.screenshot()