Printing

A library for using Compose to generated printed documents, using Android's printing services.

Gradle

dependencies {
  implementation "com.halilibo.compose-richtext:printing:${richtext_version}"
}

Usage

There are multiple entry points into this library. See their kdoc for usage and parameter documentation, and take a look at the samples for example code.

Printable

This is the simplest entry point. It's a composable function that displays its children on screen, but can also print itself. Printing is triggered by the PrintableController passed to Printable. PrintableController is a hoisted state type, just like ScrollState, created by calling rememberPrintableController.

val printController = rememberPrintableController()
Printable(printController) {
  ScrollableColumn {
    Card { … }
    Card { … }
    Button(onClick = { printController.print("sales report") }) { … }
  }
}

ComposePrintAdapter

This is a PrintDocumentAdapter that can be used directly with Android's printing APIs to print any composable function. It takes, at minimum, the ComponentActivity that owns the print adapter (as required by Android's printing framework), a string name for the document, and the composable function that defines the content to print. See the linked API documentation for more details.

Paged

This is another composable, but doesn't actually have anything to do with printing. Conceptually it's similar to a ScrollableColumn – it lays its contents out at full height, then can display them at various vertical offsets. However, it also tries to ensure that no composables are clipped at the bottom, by measuring where all the leaf composables (those without any children) are located clipping the content before them. It is used by the printing APIs to try to ensure that composable content looks decent when split into printer pages.

See the PagedSample for more information.

Demo

The DocumentSample tries to match the style of one of the Google Docs templates. It looks great on small phone screens, but also prints: