Add colorInvert modifier. (#188)

Part of #51.

Sources/Slipstream/Documentation.docc/Guides/SlipstreamForTailwindCSSDevelopers.md

@@ -185,7 +185,7 @@ Tailwind utility | Slipstream modifier
 [Drop Shadow](https://tailwindcss.com/docs/drop-shadow) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
 [Grayscale](https://tailwindcss.com/docs/grayscale) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
 [Hue Rotate](https://tailwindcss.com/docs/hue-rotate) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
-[Invert](https://tailwindcss.com/docs/invert) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
+[Invert](https://tailwindcss.com/docs/invert) | ``View/colorInvert(condition:)``
 [Saturate](https://tailwindcss.com/docs/saturate) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
 [Sepia](https://tailwindcss.com/docs/sepia) | [Not implemented yet](https://github.com/jverkoey/slipstream/issues/51)
 [Backdrop Blur](https://tailwindcss.com/docs/backdrop-blur) | ``View/background(_:condition:)-89gyc``

Sources/Slipstream/Documentation.docc/Guides/SlipstreamforSwiftUIDevelopers.md

@@ -105,6 +105,19 @@ struct MyView: View {
 }
 ```
 
+## Filters
+
+SwiftUI and Slipstream both provide the ability to invert colors.
+
+### Offset
+
+```swift
+var body: some View {
+  Text("Inverted text")
+    .colorInvert()
+}
+```
+
 ## Layout
 
 SwiftUI and Slipstream both provide the ability to affect the layout of views.

Sources/Slipstream/Documentation.docc/TailwindCSS/TailwindCSS-Utilities.md

@@ -60,6 +60,7 @@ Slipstream implementations of Tailwind CSS's utility classes.
 ### Filters
 
 - <doc:Filters-BackdropBlur>
+- ``View/colorInvert(condition:)``
 
 ### Transitions and animations
 

Sources/Slipstream/TailwindCSS/Filters/View+colorInvert.swift

@@ -0,0 +1,11 @@
+extension View {
+  /// Inverts all of the colors in a view so that each color displays as its complementary color.
+  ///
+  /// For example, blue converts to yellow, and white converts to black.
+  ///
+  /// - SeeAlso: Tailwind CSS' [invert](https://tailwindcss.com/docs/invert) documentation.
+  @available(iOS 17.0, macOS 14.0, *)
+  public func colorInvert(condition: Condition? = nil) -> some View {
+    return modifier(TailwindClassModifier(add: "invert", condition: condition))
+  }
+}

Tests/SlipstreamTests/TailwindCSS/Filters/ColorInvertTests.swift

@@ -0,0 +1,8 @@
+import Testing
+import Slipstream
+
+struct ColorInvertTests {
+  @Test func applies() throws {
+    try #expect(renderHTML(Div {}.colorInvert()) == #"<div class="invert"></div>"#)
+  }
+}