Dynamic color implementation (#76)

Sources/DarkModeCore/DMDynamicColor.h

@@ -4,6 +4,11 @@
 //
 
 @import UIKit;
+#ifdef SWIFT_PACKAGE
+#import "DMTraitCollection.h"
+#else
+#import <FluentDarkModeKit/DMTraitCollection.h>
+#endif
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -14,6 +19,7 @@ NS_SWIFT_NAME(DynamicColor)
 @property (nonatomic, readonly) UIColor *darkColor;
 
 - (instancetype)initWithLightColor:(UIColor *)lightColor darkColor:(UIColor *)darkColor;
+- (instancetype)initWithDynamicProvider:(UIColor * (^)(DMTraitCollection *traitCollection))dynamicProvider;
 
 @end
 

Sources/DarkModeCore/DMDynamicColor.m

@@ -4,12 +4,11 @@
 //
 
 #import "DMDynamicColor.h"
-#import "DMTraitCollection.h"
+#import "DMNamespace.h"
 
 @interface DMDynamicColorProxy : NSProxy <NSCopying>
 
-@property (nonatomic, strong) UIColor *lightColor;
-@property (nonatomic, strong) UIColor *darkColor;
+@property (nonatomic, strong) UIColor *(^dynamicProvider)(DMTraitCollection *);
 
 @property (nonatomic, readonly) UIColor *resolvedColor;
 
@@ -19,25 +18,48 @@
 
 // TODO: We need a more generic initializer.
 - (instancetype)initWithLightColor:(UIColor *)lightColor darkColor:(UIColor *)darkColor {
-  self.lightColor = lightColor;
-  self.darkColor = darkColor;
+  return [self initWithDynamicProvider:^(DMTraitCollection *traitCollection){
+    return traitCollection.userInterfaceStyle == DMUserInterfaceStyleDark ? darkColor : lightColor;
+  }];
+}
 
+- (instancetype)initWithDynamicProvider:(UIColor * (^)(DMTraitCollection *traitCollection))dynamicProvider {
+  self.dynamicProvider = dynamicProvider;
   return self;
 }
 
 - (UIColor *)resolvedColor {
-  if (DMTraitCollection.currentTraitCollection.userInterfaceStyle == DMUserInterfaceStyleDark) {
-    return self.darkColor;
-  } else {
-    return self.lightColor;
-  }
+  return [self resolvedColorWithTraitCollection:DMTraitCollection.currentTraitCollection];
+}
+
+- (UIColor *)resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {
+  return self.dynamicProvider(traitCollection);
 }
 
 // MARK: UIColor
 
 - (UIColor *)colorWithAlphaComponent:(CGFloat)alpha {
-  return [[DMDynamicColor alloc] initWithLightColor:[self.lightColor colorWithAlphaComponent:alpha]
-                                          darkColor:[self.darkColor colorWithAlphaComponent:alpha]];
+  return [[DMDynamicColor alloc] initWithDynamicProvider:^UIColor *(DMTraitCollection *traitCollection) {
+    return [self.dynamicProvider(traitCollection) colorWithAlphaComponent:alpha];
+  }];
+}
+
+// MARK: Methods that do not need forwarding
+
+- (UIColor *)lightColor {
+  return [self resolvedColorWithTraitCollection:[DMTraitCollection traitCollectionWithUserInterfaceStyle:DMUserInterfaceStyleLight]];
+}
+
+- (UIColor *)darkColor {
+  return [self resolvedColorWithTraitCollection:[DMTraitCollection traitCollectionWithUserInterfaceStyle:DMUserInterfaceStyleDark]];
+}
+
+- (UIColor *)dm_resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {
+  return [self resolvedColorWithTraitCollection:traitCollection];;
+}
+
+- (UIColor *)dm_namespace:(DMNamespace)namespace resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {
+  return [self dm_resolvedColorWithTraitCollection:traitCollection];
 }
 
 // MARK: NSProxy
@@ -68,7 +90,7 @@
 }
 
 - (id)copyWithZone:(NSZone *)zone {
-  return [[DMDynamicColorProxy alloc] initWithLightColor:self.lightColor darkColor:self.darkColor];
+  return [[DMDynamicColorProxy alloc] initWithDynamicProvider:[self.dynamicProvider copy]];
 }
 
 @end
@@ -81,6 +103,10 @@
   return (DMDynamicColor *)[[DMDynamicColorProxy alloc] initWithLightColor:lightColor darkColor:darkColor];
 }
 
+- (instancetype)initWithDynamicProvider:(UIColor * _Nonnull (^)(DMTraitCollection * _Nonnull))dynamicProvider {
+  return (DMDynamicColor *)[[DMDynamicColorProxy alloc] initWithDynamicProvider:dynamicProvider];
+}
+
 - (UIColor *)lightColor {
   NSAssert(NO, @"This should never be called");
   return nil;

Sources/DarkModeCore/UIColor+DarkModeKit.h

@@ -6,8 +6,10 @@
 #import <UIKit/UIKit.h>
 #ifdef SWIFT_PACKAGE
 #import "DMNamespace.h"
+#import "DMTraitCollection.h"
 #else
 #import <FluentDarkModeKit/DMNamespace.h>
+#import <FluentDarkModeKit/DMTraitCollection.h>
 #endif
 
 NS_ASSUME_NONNULL_BEGIN
@@ -16,11 +18,18 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (UIColor *)dm_colorWithLightColor:(UIColor *)lightColor darkColor:(UIColor *)darkColor
 NS_SWIFT_UNAVAILABLE("Use init(_:light:dark:) instead.");
++ (UIColor *)dm_colorWithDynamicProvider:(UIColor * (^)(DMTraitCollection *traitCollection))dynamicProvider
+NS_SWIFT_UNAVAILABLE("Use init(_:dynamicProvider:) instead.");
+- (UIColor *)dm_resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection
+NS_SWIFT_UNAVAILABLE("Use resolvedColor(_:with:) instead.");
 
 #if __swift__
 + (UIColor *)dm_namespace:(DMNamespace)namespace
       colorWithLightColor:(UIColor *)lightColor
                 darkColor:(UIColor *)darkColor NS_SWIFT_NAME(init(_:light:dark:));
++ (UIColor *)dm_namespace:(DMNamespace)namespace
+          dynamicProvider:(UIColor *(^)(DMTraitCollection *traitCollection))dynamicProvider NS_SWIFT_NAME(init(_:dynamicProvider:));
+- (UIColor *)dm_namespace:(DMNamespace)namespace resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection NS_SWIFT_NAME(resolvedColor(_:with:));
 #endif
 
 @end

Sources/DarkModeCore/UIColor+DarkModeKit.m

@@ -18,4 +18,23 @@
   return [UIColor dm_colorWithLightColor:lightColor darkColor:darkColor];
 }
 
++ (UIColor *)dm_colorWithDynamicProvider:(UIColor *(^)(DMTraitCollection *))dynamicProvider {
+  return (UIColor *)[[DMDynamicColor alloc] initWithDynamicProvider:dynamicProvider];
+}
+
++ (UIColor *)dm_namespace:(DMNamespace)namespace dynamicProvider:(UIColor *(^)(DMTraitCollection *))dynamicProvider {
+  return [self dm_colorWithDynamicProvider:dynamicProvider];
+}
+
+- (UIColor *)dm_resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {
+  // Here we just need to take care of UIColor that is not DMDynamicColor
+  // since DMDynamicColor methods are all forwarded, simply return self
+  // before we need to bridge iOS 13's color mechanism
+  return self;
+}
+
+- (UIColor *)dm_namespace:(DMNamespace)namespace resolvedColorWithTraitCollection:(DMTraitCollection *)traitCollection {
+  return [self dm_resolvedColorWithTraitCollection:traitCollection];
+}
+
 @end

Tests/FluentDarkModeKitTests/DarkModeKitTests.swift

@@ -29,6 +29,22 @@ final class DarkModeKitTests: XCTestCase {
     _ = UIImage(.dm, light: lightImage, dark: darkImage)
   }
 
+  func testDynamicColor() {
+    let color = UIColor(.dm) {
+      $0.userInterfaceStyle == .dark ? UIColor.black : UIColor.white
+    }
+
+    DMTraitCollection.current = DMTraitCollection(userInterfaceStyle: .light)
+    XCTAssertEqual(color.rgba, UIColor.white.rgba)
+
+    DMTraitCollection.current = DMTraitCollection(userInterfaceStyle: .dark)
+    XCTAssertEqual(color.rgba, UIColor.black.rgba)
+
+    // Test color fetched from specific trait collections
+    XCTAssertEqual(color.resolvedColor(.dm, with: DMTraitCollection(userInterfaceStyle: .dark)).rgba, UIColor.black.rgba)
+    XCTAssertEqual(color.resolvedColor(.dm, with: DMTraitCollection(userInterfaceStyle: .light)).rgba, UIColor.white.rgba)
+  }
+
   func testColorPropertySetters() {
     let color = UIColor(.dm, light: .white, dark: .black)