feat: Add document scanner package

packages/paperless_document_scanner/android/.gitignore

@@ -0,0 +1,9 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+.cxx

packages/paperless_document_scanner/android/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.6.0)
+include_directories(../include)
+add_library(lib_opencv SHARED IMPORTED)
+set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION ${CMAKE_CURRENT_SOURCE_DIR}/src/main/jniLibs/${ANDROID_ABI}/libopencv_java4.so)
+set(EDGE_DETECTION_DIR "../ios/Classes")
+set(SOURCES
+    ${EDGE_DETECTION_DIR}/native_edge_detection.cpp
+    ${EDGE_DETECTION_DIR}/edge_detector.cpp
+    ${EDGE_DETECTION_DIR}/image_processor.cpp
+    ${EDGE_DETECTION_DIR}/conversion_utils.cpp
+)
+add_library(native_edge_detection SHARED ${SOURCES})
+target_link_libraries(native_edge_detection lib_opencv)

packages/paperless_document_scanner/android/build.gradle

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+group 'de.astubenbord.paperless_document_scanner'
+version '1.0-SNAPSHOT'
+
+buildscript {
+    ext.kotlin_version = '1.7.10'
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:7.2.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion 31
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
+        main {
+            jniLibs.srcDirs = ['jniLibs']
+        }
+    }
+
+    defaultConfig {
+        minSdkVersion 21
+    }
+
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+
+    externalNativeBuild {
+        cmake {
+            path "CMakeLists.txt"
+        }
+    }
+
+    defaultConfig {
+        externalNativeBuild {
+            cmake {
+                cppFlags '-frtti -fexceptions -std=c++11'
+                arguments "-DANDROID_STL=c++_shared"
+            }
+        }
+    }
+}

packages/paperless_document_scanner/android/settings.gradle

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+rootProject.name = 'paperless_document_scanner'

packages/paperless_document_scanner/android/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="de.astubenbord.paperless_document_scanner">
+</manifest>

packages/paperless_document_scanner/android/src/main/kotlin/de/astubenbord/paperless_document_scanner/PaperlessDocumentScannerPlugin.kt

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+package de.astubenbord.paperless_document_scanner
+
+import androidx.annotation.NonNull
+
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler
+import io.flutter.plugin.common.MethodChannel.Result
+
+/** PaperlessDocumentScannerPlugin */
+class PaperlessDocumentScannerPlugin: FlutterPlugin, MethodCallHandler {
+  /// The MethodChannel that will the communication between Flutter and native Android
+  ///
+  /// This local reference serves to register the plugin with the Flutter Engine and unregister it
+  /// when the Flutter Engine is detached from the Activity
+  private lateinit var channel : MethodChannel
+
+  override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
+    channel = MethodChannel(flutterPluginBinding.binaryMessenger, "paperless_document_scanner")
+    channel.setMethodCallHandler(this)
+  }
+
+  override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
+    if (call.method == "getPlatformVersion") {
+      result.success("Android ${android.os.Build.VERSION.RELEASE}")
+    } else {
+      result.notImplemented()
+    }
+  }
+
+  override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
+    channel.setMethodCallHandler(null)
+  }
+}