pdfrx 0.4.13

Yet another PDF renderer for Flutter using PDFium.

pdfrx

pdfrx is a PDF viewer implementation built on the top of pdfium. The plugin currently supports Android, iOS, Windows, macOS, Linux, and Web.

Please note that "Web" is not shown in pub.dev's platform list, but IT DOES SUPPORT Web.

• A demo site using Flutter Web

Getting Started

The following fragment illustrates the easiest way to show a PDF file in assets:

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Pdfrx example'),
        ),
        body: PdfViewer.asset('assets/hello.pdf'),
      ),
    );
  }
}

Installation

Add this to your package's pubspec.yaml file and execute flutter pub get:

dependencies:
  pdfrx: ^0.4.13

Windows

• Ensure your Windows installation enables Developer Mode

  The build process internally uses symblic link and it requires Developer Mode to be enabled. Without this, you may encounter errors like this.

Web

For Web, you should add the following <script> block to your index.html just before <script src="main.dart.js"... </script> to load PDF.js:

<!-- IMPORTANT: load pdfjs files -->
<script
  src="https://cdn.jsdelivr.net/npm/pdfjs-dist@3.11.174/build/pdf.min.js"
  type="text/javascript"
></script>
<script type="text/javascript">
  pdfjsLib.GlobalWorkerOptions.workerSrc =
    "https://cdn.jsdelivr.net/npm/pdfjs-dist@3.11.174/build/pdf.worker.min.js";
  pdfRenderOptions = {
    // where cmaps are downloaded from
    cMapUrl: "https://cdn.jsdelivr.net/npm/pdfjs-dist@3.11.174/cmaps/",
    // The cmaps are compressed in the case
    cMapPacked: true,
    // any other options for pdfjsLib.getDocument.
    // params: {}
  };
</script>

Please check example's code for the actual usage.

Please note that; with pdf.js 4.0 series, they changed the way to load pdfjsLib, it does not simply work with the current code. We need further investigation to support them.

macOS

For macOS, Flutter app restrict its capability by enabling App Sandbox by default. You can change the behavior by editing your app's entitlements files depending on your configuration. See the discussion below.

• macos/Runner/Release.entitlements
• macos/Runner/DebugProfile.entitlements

Deal with App Sandbox

The easiest option to access files on your disk, set com.apple.security.app-sandbox to false on your entitlements file though it is not recommended for releasing apps because it completely disables App Sandbox.

Another option is to use com.apple.security.files.user-selected.read-only along with file_selector_macos. The option is better in security than the previous option.

Anyway, the example code for the plugin illustrates how to download and preview internet hosted PDF file. It uses com.apple.security.network.client along with flutter_cache_manager:

<dict>
  <key>com.apple.security.app-sandbox</key>
  <true/>
  <key>com.apple.security.network.client</key>
  <true/>
</dict>

Customizations

You can customize the behaviour and visual by configuring PdfViewerParams.

Horizontal Scroll View

By default, the pages are layed out vertically. You can customize the layout logic by PdfViewerParams.layoutPages:

layoutPages: (pages, params) {
  final height =
      pages.fold(0.0, (prev, page) => max(prev, page.height)) +
          params.margin * 2;
  final pageLayouts = <Rect>[];
  double x = params.margin;
  for (var page in pages) {
    pageLayouts.add(
      Rect.fromLTWH(
        x,
        (height - page.height) / 2, // center vertically
        page.width,
        page.height,
      ),
    );
    x += page.width + params.margin;
  }
  return PdfPageLayout(
    pageLayouts: pageLayouts,
    documentSize: Size(x, height),
  );
},

Showing Scroll Thumbs

By default, the viewer does never show any scroll bars nor scroll thumbs. You can add scroll thumbs by using PdfViewerParams.viewerOverlayBuilder:

viewerOverlayBuilder: (context, size) => [
  // Add vertical scroll thumb on viewer's right side
  PdfViewerScrollThumb(
    controller: controller,
    orientation: ScrollbarOrientation.right,
    thumbSize: const Size(40, 25),
    thumbBuilder:
        (context, thumbSize, pageNumber, controller) =>
            Container(
      color: Colors.black,
      // Show page number on the thumb
      child: Center(
        child: Text(
          pageNumber.toString(),
          style: const TextStyle(color: Colors.white),
        ),
      ),
    ),
  ),
  // Add horizontal scroll thumb on viewer's bottom
  PdfViewerScrollThumb(
    controller: controller,
    orientation: ScrollbarOrientation.bottom,
    thumbSize: const Size(80, 30),
    thumbBuilder:
        (context, thumbSize, pageNumber, controller) =>
            Container(
      color: Colors.red,
    ),
  ),
],

Adding Page Number on Page Bottom

If you want to add page number on each page, you can do that by PdfViewerParams.pageOverlayBuilder:

pageOverlayBuilder: (context, pageRect, page) {
  return Align(
    alignment: Alignment.bottomCenter,
    child: Text(page.pageNumber.toString(),
    style: const TextStyle(color: Colors.red)));
},