Swiftui Colors API

Colors & ShapeStyle API Reference

Lifecycle Position

Phase 3 API Reference — load during implementation when working with colors, gradients, or tints. Dispatched from autonomous-ui-workflow Phase 2 research table.

Foreground Styling

.foregroundStyle(.teal)                          // single
.foregroundStyle(.blue, .gray)                   // primary + secondary
.foregroundStyle(.blue, .gray, .gray.opacity(0.5))  // + tertiary

Hierarchical: .primary, .secondary, .tertiary, .quaternary

System Colors

.black, .blue, .brown, .clear, .cyan, .gray, .green, .indigo, .mint, .orange, .pink, .purple, .red, .teal, .white, .yellow

Tint

Button("Answer") { }.tint(.green)
Gauge(value: 75, in: 0...100) { }.tint(Gradient(colors: [.blue, .red]))

Background

.background(.regularMaterial)
.backgroundStyle(.blue.gradient)
Image(systemName: "swift").padding().background(in: Circle()).backgroundStyle(.blue.gradient)

Gradients

.linearGradient(colors: [.yellow, .blue], startPoint: .top, endPoint: .bottom)
.radialGradient(Gradient(colors: [.yellow, .red]), center: .topLeading, startRadius: 15, endRadius: 80)
Color.blue.gradient  // standard gradient from color

Color Modifiers

Color.blue.opacity(0.5)
Color.red.mix(with: .blue, by: 0.5)

Custom ShapeStyle

struct MyStyle: ShapeStyle {
    func resolve(in environment: EnvironmentValues) -> some ShapeStyle {
        environment.colorScheme == .light ? Color.red.blendMode(.lighten) : Color.red.blendMode(.darken)
    }
}

When to Use Which

Common Mistakes

1. Using Color.black/Color.white instead of .primary/semantic colors — breaks in dark mode
2. Hardcoding hex colors instead of asset catalog — no dark mode variant, no accessibility
3. Using foregroundColor() instead of foregroundStyle() — deprecated API
4. Applying .tint() and .foregroundStyle() together — tint overrides foregroundStyle on controls
5. Missing .opacity() consideration — semantic colors already have built-in opacity levels

Before (incorrect):

Text("Hello")
    .foregroundColor(.black)  // deprecated, breaks dark mode

After (correct):

Text("Hello")
    .foregroundStyle(.primary)  // adapts to dark mode automatically

Before (incorrect):

Color(hex: "#FF3B30")  // hardcoded, no dark mode variant

After (correct):

Color("BrandRed")  // defined in asset catalog with Light/Dark variants

Checklist

• No hardcoded Color.black/Color.white for text or backgrounds
• Using foregroundStyle() not foregroundColor()
• Brand colors defined in asset catalog with dark mode variants
• Gradient direction matches reading direction (leading → trailing)
• Color contrast meets WCAG AA (4.5:1 for normal text, 3:1 for large text)

Cross-References

• swiftui-effects-api — blur, shadow, opacity effects that interact with colors
• swiftui-material-api — material backgrounds that adapt to underlying colors
• swiftui-ui-patterns — modern API checklist includes foregroundStyle() migration