Enhancement: Direct Filter Application Without Controller

[alodevloper]

Description: I would like to request a feature or modification that would allow applying filters directly to an image without needing to use the FlutterDocumentScannerController. Currently, the filter application is tied to the controller, but it would be very useful if we could apply filters directly by passing the image in Uint8List format and selecting the filter type (e.g., grayscale, invert).

Proposed Feature:

Allow direct image manipulation via the applyFilter method without requiring a controller.
The method should accept Uint8List as the input image and return the processed image (also as Uint8List).
This would allow for easier integration of the filter functionality in scenarios where the controller isn't needed.
Use Case:

I want to apply filters to an image before displaying it or processing it further, but I don't need to interact with the scanning features of the controller.