PDF Viewer library for Kotlin Multiplatform and Compose Multiplatform.

This library wraps libpdfium (the Chromium PDF engine). The pre-compiled pdfium files are taken from here and bundled into this library.

Supported targets

• Android
• JVM Desktop
  • Linux x64, ARM64
  • Windows X64
  • MacOS X64, ARM64
• iOS
  • x64 (simulator)
  • arm64
  • arm64Simulator

Usage

Add the dependency

implementation("com.dshatz.pdfmp:pdfmp-compose:1.0.9")

pdfmp = { module = "com.dshatz.pdfmp:pdfmp-compose", version = "1.0.9" }

Load the pdf

From bytes

  val pdf = PdfSource.PdfBytes(byteArray)

From path

val pdf = PdfSource.PdfPath(Path("~/Download/sample.pdf")

From Compose Resources

You can use this helper.

val bytes: PdfBytes? by asyncPdfResource { 
    Res.readBytes("files/doc.pdf")
}

Display the document.

To create a PdfState, you need only an instance of PdfSource.

Additionally, you can pass some optional parameters:

• pageRange: IntRange - range of pages to include. Zero-indexed, inclusive range.
• pageSpacing: Dp - spacing between pages, in DP.

@Composable
fun ShowDoc(state: PdfState) {
    val state = rememberPdfState(pdf, pageSpacing = 100.dp)
    PdfView(state, Modifier.fillMaxSize())
}

Observing document state

Use val displayState by state.displayState to get the document state.

sealed class DisplayState {
    data object Initializing: DisplayState()
    data object Active: DisplayState()
    data class Error(val error: Throwable): DisplayState()
}

You can use this to display a loading indicator or an error dialog.

Controlling the document view

You can read and change various view parameters.

val layoutInfo by state.layoutInfo()
// It will be null if the document did not load yet.
layoutInfo?.apply {
    // Below is some of the available state

    val visiblePages: State<List<VisiblePageInfo>>
    val mostVisiblePage: State<VisiblePageInfo?>
    val totalPages: State<Int>
    val pageRange: State<IntRange>
    val documentHeight: State<Float>

    // Scroll related
    var offsetY: Float
    fun scrollTo(pageIdx: Int)
    suspend fun animateScrollTo(pageIdx: Int)

    // Zoom related
    val zoom: State<Float>
    fun setZoom(newZoom: Float)
    suspend fun animateSetZoom(newZoom: Float)
}

Features

Feature	Supported	Notes
Loading from bytes	✅
Loading from path	✅	May not work on Android, depending on permissions and path. Please report.
Loading from compose resources	❌	Does not work directly because native code does not have access to it. See above for how to do it.
Zooming and scrolling	✅	Loading the high-res image is debounced by 100ms. On desktop, horizontal scrolling can only be done with Shift+Vertical scroll.
Filtering pages	✅	Pass page range to rememberPdfState