feat: Add document scanner package

packages/paperless_document_scanner/lib/modules/edge_detection.dart

@@ -0,0 +1,87 @@
+import 'dart:ffi';
+import 'dart:io';
+import 'dart:typed_data';
+import 'dart:ui';
+
+import 'package:ffi/ffi.dart';
+import 'package:paperless_document_scanner/types/edge_detection_result.dart';
+
+final DynamicLibrary _nativeInteropLib = Platform.isAndroid
+    ? DynamicLibrary.open("libnative_edge_detection.so")
+    : DynamicLibrary.process();
+
+class EdgeDetection {
+  static Future<EdgeDetectionResult> detectEdgesFromFile(String path) async {
+    final detectEdges = _nativeInteropLib
+        .lookup<NativeFunction<_c_detect_edges_from_file>>(
+            "detect_edges_from_file")
+        .asFunction<_dart_detect_edges_from_file>();
+
+    NativeEdgeDetectionResult detectionResult =
+        detectEdges(path.toNativeUtf8()).ref;
+
+    return EdgeDetectionResult(
+        topLeft: Offset(
+            detectionResult.topLeft.ref.x, detectionResult.topLeft.ref.y),
+        topRight: Offset(
+            detectionResult.topRight.ref.x, detectionResult.topRight.ref.y),
+        bottomLeft: Offset(
+            detectionResult.bottomLeft.ref.x, detectionResult.bottomLeft.ref.y),
+        bottomRight: Offset(detectionResult.bottomRight.ref.x,
+            detectionResult.bottomRight.ref.y));
+  }
+
+  static Future<EdgeDetectionResult> detectEdges(Uint8List bytes) async {
+    final detectEdges = _nativeInteropLib
+        .lookup<NativeFunction<_c_detect_edges>>("detect_edges")
+        .asFunction<_dart_detect_edges>();
+
+    Pointer<Uint8> imgBuffer = malloc.allocate<Uint8>(bytes.lengthInBytes);
+    Uint8List buffer = imgBuffer.asTypedList(bytes.lengthInBytes);
+    buffer.setAll(0, bytes);
+
+    NativeEdgeDetectionResult detectionResult = detectEdges(
+      imgBuffer,
+      buffer.lengthInBytes,
+    ).ref;
+
+    final result = EdgeDetectionResult(
+      topLeft: Offset(
+        detectionResult.topLeft.ref.x,
+        detectionResult.topLeft.ref.y,
+      ),
+      topRight: Offset(
+        detectionResult.topRight.ref.x,
+        detectionResult.topRight.ref.y,
+      ),
+      bottomLeft: Offset(
+        detectionResult.bottomLeft.ref.x,
+        detectionResult.bottomLeft.ref.y,
+      ),
+      bottomRight: Offset(
+        detectionResult.bottomRight.ref.x,
+        detectionResult.bottomRight.ref.y,
+      ),
+    );
+    return result;
+  }
+}
+
+typedef _c_detect_edges_from_file = Pointer<NativeEdgeDetectionResult> Function(
+  Pointer<Utf8> imagePath,
+);
+
+typedef _c_detect_edges = Pointer<NativeEdgeDetectionResult> Function(
+  Pointer<Uint8> bytes,
+  Int32 byteSize,
+);
+
+typedef _dart_detect_edges_from_file = Pointer<NativeEdgeDetectionResult>
+    Function(
+  Pointer<Utf8> imagePath,
+);
+
+typedef _dart_detect_edges = Pointer<NativeEdgeDetectionResult> Function(
+  Pointer<Uint8> bytes,
+  int byteSize,
+);

packages/paperless_document_scanner/lib/modules/image_processing.dart

@@ -0,0 +1,112 @@
+import 'dart:ffi';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:ffi/ffi.dart';
+import 'package:paperless_document_scanner/types/edge_detection_result.dart';
+
+final DynamicLibrary _nativeInteropLib = Platform.isAndroid
+    ? DynamicLibrary.open("libnative_edge_detection.so")
+    : DynamicLibrary.process();
+
+class ImageProcessing {
+  static Future<bool> processImageFromFile(
+    String path,
+    EdgeDetectionResult result,
+  ) async {
+    final processImage = _nativeInteropLib
+        .lookup<NativeFunction<_c_process_image_from_file>>(
+            "process_image_from_file")
+        .asFunction<_dart_process_image_from_file>();
+
+    return processImage(
+          path.toNativeUtf8(),
+          result.topLeft.dx,
+          result.topLeft.dy,
+          result.topRight.dx,
+          result.topRight.dy,
+          result.bottomLeft.dx,
+          result.bottomLeft.dy,
+          result.bottomRight.dx,
+          result.bottomRight.dy,
+        ) ==
+        1;
+  }
+
+  static Future<bool> processImage(
+    Uint8List bytes,
+    EdgeDetectionResult result,
+  ) async {
+    final processImage = _nativeInteropLib
+        .lookup<NativeFunction<_c_process_image>>("process_image")
+        .asFunction<_dart_process_image>();
+
+    final imgBuffer = malloc.allocate<Uint8>(bytes.lengthInBytes);
+    Uint8List buffer = imgBuffer.asTypedList(bytes.lengthInBytes);
+    buffer.setAll(0, bytes);
+
+    return processImage(
+          imgBuffer,
+          bytes.lengthInBytes,
+          result.topLeft.dx,
+          result.topLeft.dy,
+          result.topRight.dx,
+          result.topRight.dy,
+          result.bottomLeft.dx,
+          result.bottomLeft.dy,
+          result.bottomRight.dx,
+          result.bottomRight.dy,
+        ) ==
+        1;
+  }
+}
+
+typedef _c_process_image_from_file = Int8 Function(
+  Pointer<Utf8> imagePath,
+  Double topLeftX,
+  Double topLeftY,
+  Double topRightX,
+  Double topRightY,
+  Double bottomLeftX,
+  Double bottomLeftY,
+  Double bottomRightX,
+  Double bottomRightY,
+);
+
+typedef _c_process_image = Int8 Function(
+  Pointer<Uint8> imagePath,
+  Int32 byteSize,
+  Double topLeftX,
+  Double topLeftY,
+  Double topRightX,
+  Double topRightY,
+  Double bottomLeftX,
+  Double bottomLeftY,
+  Double bottomRightX,
+  Double bottomRightY,
+);
+
+typedef _dart_process_image_from_file = int Function(
+  Pointer<Utf8> imagePath,
+  double topLeftX,
+  double topLeftY,
+  double topRightX,
+  double topRightY,
+  double bottomLeftX,
+  double bottomLeftY,
+  double bottomRightX,
+  double bottomRightY,
+);
+
+typedef _dart_process_image = int Function(
+  Pointer<Uint8> imagePath,
+  int byteSize,
+  double topLeftX,
+  double topLeftY,
+  double topRightX,
+  double topRightY,
+  double bottomLeftX,
+  double bottomLeftY,
+  double bottomRightX,
+  double bottomRightY,
+);

packages/paperless_document_scanner/lib/paperless_document_scanner.dart

@@ -0,0 +1,2 @@
+export 'modules/edge_detection.dart';
+export 'modules/image_processing.dart';

packages/paperless_document_scanner/lib/types/edge_detection_result.dart

@@ -0,0 +1,49 @@
+import 'dart:ui';
+
+import 'package:ffi/ffi.dart';
+import 'dart:ffi';
+
+class Coordinate extends Struct {
+  @Double()
+  external double x;
+
+  @Double()
+  external double y;
+
+  factory Coordinate.allocate(double x, double y) => malloc<Coordinate>().ref
+    ..x = x
+    ..y = y;
+}
+
+class NativeEdgeDetectionResult extends Struct {
+  external Pointer<Coordinate> topLeft;
+  external Pointer<Coordinate> topRight;
+  external Pointer<Coordinate> bottomLeft;
+  external Pointer<Coordinate> bottomRight;
+
+  factory NativeEdgeDetectionResult.allocate(
+    Pointer<Coordinate> topLeft,
+    Pointer<Coordinate> topRight,
+    Pointer<Coordinate> bottomLeft,
+    Pointer<Coordinate> bottomRight,
+  ) =>
+      malloc<NativeEdgeDetectionResult>().ref
+        ..topLeft = topLeft
+        ..topRight = topRight
+        ..bottomLeft = bottomLeft
+        ..bottomRight = bottomRight;
+}
+
+class EdgeDetectionResult {
+  final Offset topLeft;
+  final Offset topRight;
+  final Offset bottomLeft;
+  final Offset bottomRight;
+
+  EdgeDetectionResult({
+    required this.topLeft,
+    required this.topRight,
+    required this.bottomLeft,
+    required this.bottomRight,
+  });
+}