Rework SaveConfig for web & multi sensors

[apalala-dev]

Description

This PR intends to give more informations about which picture was taken (which sensor took it). It should also provide a better web support with the use of the cross_file package.

• Instead of a FilePathBuilder, it now takes CaptureRequestBuilder
  • It takes a List<Sensor> as argument
  • It returns a either a SingleCaptureRequest or a MultipleCaptureRequest depending on the number of sensors required
• SaveConfig has a default value for CaptureRequestBuilder. Medias will be saved at [temporary directory]/camerawesome/[time in millis].jpg
• A CaptureRequest uses XFile instead of String to better support Web (e.g.: file property for a SingleCaptureRequest)
• On Web, the files may be null since the XFile will be built by the camera implementation without a real path.
• The MediaCapture object now contains a CaptureRequest instead of a path (String).
  • It it was a success, the file(s) it contains should not be null.
• Since a CaptureRequest can either be a SingleCaptureRequest or a MultipleCaptureRequest, a when operator is introduced to deal with these without explicit casting on the dev side.
• A dependency to XFile may be added to let users specify their own path in the SaveConfig with the current implementation. An alternative would be to create our own File class and convert it to XFile when we want to work with it.

Checklist

Before creating any Pull Request, confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).

• [x] 📕 I read the Contributing page.
• [x] 🤝 I match the actual coding style.
• [x] ✅ I ran flutter analyze without any issues.

Breaking Change

• [x] 🛠 My feature contain breaking change.

Introduction of the CaptureRequest concept to deal with multiple pictures and ease the CamerAwesome web implementation.

[g-apparence]

Nice refactor ! How can we force download to

• custom path
• download folder
• application folder

[apalala-dev]

Nice refactor ! How can we force download to

• custom path
• download folder
• application folder

Here is an example for the download folder, with a different name for each picture on multicam:

CameraAwesomeBuilder.awesome(
    saveConfig: SaveConfig.photoAndVideo(
      initialCaptureMode: CaptureMode.photo,
      photoPathBuilder: (sensors) async {
        final Directory? extDir = await getDownloadsDirectory();
        final testDir = await Directory(
          '${extDir!.path}/camerawesome',
        ).create(recursive: true);
        if (sensors.length == 1) {
          final String filePath =
              '${testDir.path}/${DateTime.now().millisecondsSinceEpoch}.jpg';
          return SingleCaptureRequest(XFile(filePath), sensors.first);
        } else {
          // Separate pictures taken with front and back camera
          return MultipleCaptureRequest({
            for (final sensor in sensors)
              sensor: XFile(
                '${testDir.path}/${sensor.position == SensorPosition.front ? 'front_' : "back_"}${DateTime.now().millisecondsSinceEpoch}.jpg',
              )
          });
        }
      },
    ),
);

One downside of this solution is that the app using CamerAwesome must also add a cross_file and a path_provider dependency to set a custom save path.

[g-apparence]

Maybe we could make this simpler ?

[apalala-dev]

Maybe we could make this simpler ?

I don't think we can simplify the part to specify the path (retrieving the directory, creating it if it doesn't exist, building the filePath). After that, I separated as an example if there was one or more sensors taking pictures, but in most cases it will only use the first part. However, the need to build an XFile (and by doing so, adding a dependancy in the client side to cross_file) does not seem very nice to me. We probably could just pass the path and build an XFile in the lib.

Feel free to share any other idea 😅