# ViewModifier A modifier that you apply to a view or another view modifier, producing a different version of the original value. ``` @MainActor @preconcurrency protocol ViewModifier ``` ## Overview Adopt the [`ViewModifier`](/documentation/SwiftUI/ViewModifier) protocol when you want to create a reusable modifier that you can apply to any view. The example below combines several modifiers to create a new modifier that you can use to create blue caption text surrounded by a rounded rectangle: ``` struct BorderedCaption: ViewModifier { func body(content: Content) -> some View { content .font(.caption2) .padding(10) .overlay( RoundedRectangle(cornerRadius: 15) .stroke(lineWidth: 1) ) .foregroundColor(Color.blue) } } ``` You can apply [`modifier(_:)`](/documentation/SwiftUI/View/modifier(_:)) directly to a view, but a more common and idiomatic approach uses [`modifier(_:)`](/documentation/SwiftUI/View/modifier(_:)) to define an extension to [`View`](/documentation/SwiftUI/View) itself that incorporates the view modifier: ``` extension View { func borderedCaption() -> some View { modifier(BorderedCaption()) } } ``` You can then apply the bordered caption to any view, similar to this: ``` Image(systemName: "bus") .resizable() .frame(width:50, height:50) Text("Downtown Bus") .borderedCaption() ```  A type conforming to this protocol inherits `@preconcurrency @MainActor` isolation from the protocol if the conformance is included in the type’s base declaration: ``` struct MyCustomType: Transition { // `@preconcurrency @MainActor` isolation by default } ``` Isolation to the main actor is the default, but it’s not required. Declare the conformance in an extension to opt out of main actor isolation: ``` extension MyCustomType: Transition { // `nonisolated` by default } ``` ## Topics ### Creating a view modifier [`body(content:)`](/documentation/SwiftUI/ViewModifier/body(content:)) Gets the current body of the caller. [`Body`](/documentation/SwiftUI/ViewModifier/Body) The type of view representing the body. [`ViewModifier.Content`](/documentation/SwiftUI/ViewModifier/Content) The content view type passed to `body()`. ### Adding animations to a view [`animation(_:)`](/documentation/SwiftUI/ViewModifier/animation(_:)) Returns a new version of the modifier that will apply `animation` to all animatable values within the modifier. [`concat(_:)`](/documentation/SwiftUI/ViewModifier/concat(_:)) Returns a new modifier that is the result of concatenating `self` with `modifier`. ### Handling view taps and gestures [`transaction(_:)`](/documentation/SwiftUI/ViewModifier/transaction(_:)) Returns a new version of the modifier that will apply the transaction mutation function `transform` to all transactions within the modifier. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)