fix: parse hexadecimal and 8-bit .colorset color components (#146)

Sources/SkipUI/SkipUI/Color/Color.swift

@@ -623,15 +623,46 @@ private struct ColorSet : Decodable {
         let alpha: String?
 
         var color: Color {
-            let redValue = Double(red ?? "") ?? 0.0
-            let greenValue = Double(green ?? "") ?? 0.0
-            let blueValue = Double(blue ?? "") ?? 0.0
-            let alphaValue = Double(alpha ?? "") ?? 1.0
+            let redValue = parseColorComponent(red, defaultValue: 0.0)
+            let greenValue = parseColorComponent(green, defaultValue: 0.0)
+            let blueValue = parseColorComponent(blue, defaultValue: 0.0)
+            let alphaValue = parseColorComponent(alpha, defaultValue: 1.0)
             return Color(red: redValue, green: greenValue, blue: blueValue, opacity: alphaValue)
         }
     }
 }
 
+/// Parse a single `.colorset` channel, covering all of Xcode's numeric "Input Method" variants:
+/// Floating Point ("0.945", passed through unchanged), 8-bit Hexadecimal ("0xF1" / "#F1"), and
+/// 8-bit (0-255) ("241"). Hex bytes and 0-255 integers are normalized to 0...1 by dividing by 255.
+/// Malformed or empty input falls back to `defaultValue`. See https://github.com/skiptools/skip-ui/issues/146
+///
+/// The hex prefix is detected explicitly rather than relying on `Double(_:)` to reject it: Swift
+/// parses `Double("0xF1")` as `241.0`, whereas the transpiled Kotlin `"0xF1".toDoubleOrNull()` is
+/// `null`. A "try Double first" approach would therefore behave differently once transpiled (and is
+/// the reason #146 manifests only on Android). Checking the prefix keeps both platforms identical.
+/// Hex digits are parsed with Kotlin's `toIntOrNull(radix:)` because Swift's `Int(_:radix:)` does not
+/// transpile. This is a free function rather than a method on `ColorComponents` because adding a
+/// `static` member to that `Decodable` type breaks Skip's reflection-based JSON decoding of `ColorSet`.
+private func parseColorComponent(_ string: String?, defaultValue: Double) -> Double {
+    guard let string, !string.isEmpty else { return defaultValue }
+    if string.hasPrefix("0x") || string.hasPrefix("0X") {
+        let byte: Int? = String(string.dropFirst(2)).toIntOrNull(radix: 16)
+        if let byte { return Double(byte) / 255.0 }
+        return defaultValue
+    }
+    if string.hasPrefix("#") {
+        let byte: Int? = String(string.dropFirst(1)).toIntOrNull(radix: 16)
+        if let byte { return Double(byte) / 255.0 }
+        return defaultValue
+    }
+    // Floating Point emits a decimal ("0.580"); the "8-bit (0-255)" method emits a bare integer ("148").
+    if !string.contains("."), let intValue = Int(string) {
+        return Double(intValue) / 255.0
+    }
+    return Double(string) ?? defaultValue
+}
+
 #endif
 
 /*

Tests/SkipUITests/ColorTests.swift

@@ -14,6 +14,42 @@ final class ColorTests: XCSnapshotTestCase {
         XCTAssertEqual("F", try render(compact: 1, view: Color.white.frame(width: 1.0, height: 1.0)).pixmap)
     }
 
+    // Issue #146: a custom .colorset authored with Xcode's "8-bit Hexadecimal" input method (channels
+    // like "0xF1") rendered as pure black on Android, because Double("0xF1") returned nil and every
+    // channel fell back to 0.0. These tests render fixtures from the test bundle and are guarded to the
+    // transpiled (SKIP) side: on Apple platforms Color(_:bundle:) defers to SwiftUI's own asset loader,
+    // so the buggy parsing path only exists under SKIP.
+
+    // The two tests below validate the issue #146 fix end-to-end by rendering custom `.colorset` assets.
+    // They are DISABLED-prefixed (this file's convention for tests that don't run in the standard pass)
+    // because decoding a bundled component `.colorset` currently fails under the Robolectric *unit* runner:
+    // `JSONDecoder().decode(ColorSet.self, …)` throws a kotlin-reflect `IllegalAccessException` on the JVM.
+    // It works on a real Android device — which is where #146 was reported (hex colorsets rendered *black*,
+    // i.e. decode succeeded and only the parse was wrong). The failure is independent of this fix: it occurs
+    // in `ColorSet` decoding, before `parseColorComponent` is ever reached. Run these on an emulator/device
+    // to validate; the parsing algorithm itself is covered by the contribution's standalone logic harness.
+
+    func DISABLEDtestHexColorset() throws {
+        // 0x04/0xF1/0x88 must render the real color (#04F188), not black (pre-fix it rendered "0").
+        #if SKIP
+        XCTAssertEqual("04F188", try render(compact: 1, view: Color("HexColor", bundle: .module).frame(width: 1.0, height: 1.0)).pixmap)
+        #endif
+    }
+
+    func DISABLEDtestFloatColorset() throws {
+        // The identical color authored as floats must render the same #04F188 (hex path == float path).
+        #if SKIP
+        XCTAssertEqual("04F188", try render(compact: 1, view: Color("FloatColor", bundle: .module).frame(width: 1.0, height: 1.0)).pixmap)
+        #endif
+    }
+
+    func DISABLEDtestIntColorset() throws {
+        // The identical color authored with the "8-bit (0-255)" method (4/241/136) must render #04F188.
+        #if SKIP
+        XCTAssertEqual("04F188", try render(compact: 1, view: Color("IntColor", bundle: .module).frame(width: 1.0, height: 1.0)).pixmap)
+        #endif
+    }
+
     // Disabled tests (due to slow performance when running against emulator)
 
     func DISABLEDtestColorClearDark() throws {

Tests/SkipUITests/Resources/Assets.xcassets/FloatColor.colorset/Contents.json

@@ -0,0 +1,20 @@
+{
+  "colors" : [
+    {
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "1.000",
+          "blue" : "0.533333",
+          "green" : "0.945098",
+          "red" : "0.015686"
+        }
+      },
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Tests/SkipUITests/Resources/Assets.xcassets/HexColor.colorset/Contents.json

@@ -0,0 +1,20 @@
+{
+  "colors" : [
+    {
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "1.000",
+          "blue" : "0x88",
+          "green" : "0xF1",
+          "red" : "0x04"
+        }
+      },
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

Tests/SkipUITests/Resources/Assets.xcassets/IntColor.colorset/Contents.json

@@ -0,0 +1,20 @@
+{
+  "colors" : [
+    {
+      "color" : {
+        "color-space" : "srgb",
+        "components" : {
+          "alpha" : "255",
+          "blue" : "136",
+          "green" : "241",
+          "red" : "4"
+        }
+      },
+      "idiom" : "universal"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}