Highlight

Cross-platform text highlighting and syntax highlighting for Compose and View, using regular expressions.

Objective

Facilitate the creation of dynamic highlights using regular expressions, ideal for code editors or text editors with custom formatting.

Supported Platforms

Platform	Support
Android with Jetpack Compose	✅
Android with View	✅
Compose for Desktop	✅
Compose for Web	✅
Compose for iOS	❌

Quick Start

The main class is Highlight, which generates formatted text in types like SpannedString or AnnotatedString, depending on the platform.

You can pass a list of schemes directly through the constructor.

Usage Example

val highlight = Highlight(
    TextColorScheme(
        regex = "\\bcolor\\b".toRegex(),
        match = Match.fully(UiColor.Black)
    )
)

// Jetpack Compose
val annotatedString = highlight.toAnnotatedString("Foreground color example.")

// View-based
val spannedString = highlight.toSpannedString("Foreground color example.")

Or use the builder scope to create patterns:

val highlight = Highlight {
    textColor {
        fully(
            regex = "\\bcolor\\b".toRegex(),
            value = UiColor.Black
        )
    }
}

// Jetpack Compose
val annotatedString = highlight.toAnnotatedString("Foreground color example.")

// View-based
val spannedString = highlight.toSpannedString("Foreground color example.")

Compose

In Compose environments, use rememberAnnotatedString to integrate highlighting into a Text component.

Usage Example

val highlight = rememberHighlight {
    spanStyle {
        fully(
            regex = "\\bstyled\\b".toRegex(),
            value = SpanStyle(
                color = Color.White,
                background = Color.Black,
                fontStyle = FontStyle.Italic,
            )
        )
    }
}

Text(
    text = highlight.rememberAnnotatedString(
        "Example of styled text."
    )
)

Or use rememberTextFieldValue for TextFieldValue:

val textFieldValue = rememberSaveable { mutableStateOf(TextFieldValue()) }

BasicTextField(
    value = highlight.rememberTextFieldValue(
        textFieldValue.value
    ).copy(
        composition = null
    ),
    onValueChange = {
        textFieldValue.value = it
    }
)

View-Based

In View-based environments, use toSpannedString, or apply to apply highlights.

Usage Example

val highlight = Highlight {
    backgroundColor {
        fully(
            regex = "\\bcolor\\b".toRegex(),
            value = UiColor.Blue
        )
    }
    textColor {
        fully(
            regex = "\\bcolor\\b".toRegex(),
            value = UiColor.White
        )
    }
}

// TextView
binding.tvExample.text = highlight.toSpannedString(
    "Background color example."
)

// EditText (Editable or Spannable)
highlight.apply(binding.etExample)

Groups

Instead of applying the highlight to the entire match using Match.fully(..), you can separate it by groups, allowing for more complex and specific highlights.

Usage Example

val highlight = rememberHighlight {
    textColor {
        groups(
            regex = "(\\w+)\\s*=\\s*(\\w+)".toRegex(),
            UiColor.Blue,
            UiColor.Green
        )
    }
}

Text(
    text = highlight.rememberAnnotatedString("name = Highlight")
)

Screenshots

Simple example	Code highlight

Installation

To integrate the Highlight library into your project, you can add it directly from the Maven Central repository.

Gradle (Kotlin DSL)

Add the following dependencies to your build.gradle.kts file:

dependencies {
    // For highlighting in Views
    implementation("com.neoutils.highlight:highlight-view:2.2.0")
    
    // For highlighting in Compose
    implementation("com.neoutils.highlight:highlight-compose:2.2.0")
}