flutter_desktop_scanner

Making scanning with physical scanners on desktop a breeze!

Getting Started

Because this plugin depends on some system libraries (SANE, WIA) you have to set up them up for linking in your flutter project.

Linux

Here's how to setup linking

In ./linux/CMakeLists.txt under:

apply_standard_settings(${BINARY_NAME})

add:

set(LINKER_FLAGS "-lsane")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${LINKER_FLAGS}")

Windows

Nothing to do here! WIA is generally available as a header file.

MacOS

Nothing to do here! MacOS uses the ImagCaptureCore framework which should be available since 10.14.

Using the plugin

Because the scanning process for devices, as well as the literal scanning, takes some time the plugin is based on EventChannels. EventChannels are like MethodChannels but for streams, which allow for getting data from native platforms via a stream. Because of that you always have to get a stream reference before initiating an action.

Here's how to get devices:

final _flutterDesktopScannerPlugin = FlutterDesktopScannerPlugin();

...

// always get the stream first
final scannerStream = _flutterDesktopScannerPlugin.getDevicesStream();

scannerStream.listen((scanners) {
    setState(() {
    _scanners = scanners;
    _loading = false;
    });
});

// then call the init method
await _flutterDesktopScannerPlugin.initGetDevices();

And here how you can initiate a scan:

final _flutterDesktopScannerPlugin = FlutterDesktopScannerPlugin();

...

// again get the stream first;
// imageReprStream returns a Image class that can be
// encoded into any image format
final stream = _flutterDesktopScannerPlugin.imageReprStream();

stream.listen((image) {
    setState(() {
    if (image != null) {
        _imgBytes = img.encodePng(image);
    }
    _imgLoading = false;
    });
});

// and then init the scan
await _flutterDesktopScannerPlugin.initScan(scanner);

Scan representations

imageReprStream: This stream returns an Image class that can be encoded into any image format (JPG, PNG, ...) for a full list see here

rawBytesStream: This stream returns a Uint8List containing the raw image bytes.
The format is different on each platform:

For linux it's PNM.
For windows it's (most likely) one of BMP / TIFF.
For MacOS it's PNG.