Merge pull request #411 from juliansteenbakker/feature/scan-window

feat: add scan window overlay and area

Merge pull request #411 from juliansteenbakker/feature/scan-window
feat: add scan window overlay and area
Julian Steenbakker · GitHub
Commit 1003c483d9f509baab6a3548bec64b2ab86cfc33 1003c483 2 parents 06668019 6b88d63c
Showing 11 changed files with 554 additions and 8 deletions
android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
example/ios/Runner.xcodeproj/project.pbxproj
example/lib/barcode_scanner_window.dart
example/lib/main.dart
ios/Classes/SwiftMobileScannerPlugin.swift
lib/src/barcode_utility.dart
lib/src/mobile_scanner.dart
lib/src/mobile_scanner_controller.dart
lib/src/objects/barcode_capture.dart
macos/Classes/MobileScannerPlugin.swift
--- a/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
View file @1003c48
+++ b/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt
View file @1003c48
@@ -3,9 +3,11 @@ package dev.steenbakker.mobile_scanner
 import android.Manifest
 import android.app.Activity
 import android.content.pm.PackageManager
+import android.graphics.Rect
 import android.net.Uri
 import android.os.Handler
 import android.os.Looper
+import android.util.Log
 import android.view.Surface
 import androidx.camera.core.*
 import androidx.camera.lifecycle.ProcessCameraProvider
@@ -14,18 +16,23 @@ import androidx.core.content.ContextCompat
 import androidx.lifecycle.LifecycleOwner
 import com.google.mlkit.vision.barcode.BarcodeScannerOptions
 import com.google.mlkit.vision.barcode.BarcodeScanning
+import com.google.mlkit.vision.barcode.common.Barcode
 import com.google.mlkit.vision.common.InputImage
 import dev.steenbakker.mobile_scanner.objects.DetectionSpeed
 import dev.steenbakker.mobile_scanner.objects.MobileScannerStartParameters
 import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.PluginRegistry
 import io.flutter.view.TextureRegistry
-typealias MobileScannerCallback = (barcodes: List<Map<String, Any?>>, image: ByteArray?) -> Unit
+import kotlin.math.roundToInt
+
+
+typealias MobileScannerCallback = (barcodes: List<Map<String, Any?>>, image: ByteArray?, width: Int?, height: Int?) -> Unit
 typealias AnalyzerCallback = (barcodes: List<Map<String, Any?>>?) -> Unit
 typealias MobileScannerErrorCallback = (error: String) -> Unit
 typealias TorchStateCallback = (state: Int) -> Unit
 typealias MobileScannerStartedCallback = (parameters: MobileScannerStartParameters) -> Unit
+
 class NoCamera : Exception()
 class AlreadyStarted : Exception()
 class AlreadyStopped : Exception()
@@ -53,6 +60,7 @@ class MobileScanner(
     private var pendingPermissionResult: MethodChannel.Result? = null
     private var preview: Preview? = null
     private var textureEntry: TextureRegistry.SurfaceTextureEntry? = null
+    var scanWindow: List<Float>? = null
     private var detectionSpeed: DetectionSpeed = DetectionSpeed.NO_DUPLICATES
     private var detectionTimeout: Long = 250
@@ -138,12 +146,27 @@ class MobileScanner(
                     lastScanned = newScannedBarcodes
                 }
-                val barcodeMap = barcodes.map { barcode -> barcode.data }
+                val barcodeMap: MutableList<Map<String, Any?>> = mutableListOf()
+
+                for ( barcode in barcodes) {
+                    if(scanWindow != null) {
+                        val match = isbarCodeInScanWindow(scanWindow!!, barcode, imageProxy)
+                        if(!match) {
+                            continue
+                        } else {
+                            barcodeMap.add(barcode.data)
+                        }
+                    } else {
+                        barcodeMap.add(barcode.data)
+                    }
+                }
                 if (barcodeMap.isNotEmpty()) {
                     mobileScannerCallback(
                         barcodeMap,
-                        if (returnImage) mediaImage.toByteArray() else null
+                        if (returnImage) mediaImage.toByteArray() else null,
+                        if (returnImage) mediaImage.width else null,
+                        if (returnImage) mediaImage.height else null
                     )
                 }
             }
@@ -162,6 +185,23 @@ class MobileScanner(
         }
     }
+    // scales the scanWindow to the provided inputImage and checks if that scaled
+    // scanWindow contains the barcode
+    private fun isbarCodeInScanWindow(scanWindow: List<Float>, barcode: Barcode, inputImage: ImageProxy): Boolean {
+        val barcodeBoundingBox = barcode.boundingBox ?: return false
+
+        val imageWidth = inputImage.height
+        val imageHeight = inputImage.width
+
+        val left = (scanWindow[0] * imageWidth).roundToInt()
+        val top = (scanWindow[1] * imageHeight).roundToInt()
+        val right = (scanWindow[2] * imageWidth).roundToInt()
+        val bottom = (scanWindow[3] * imageHeight).roundToInt()
+
+        val scaledScanWindow = Rect(left, top, right, bottom)
+        return scaledScanWindow.contains(barcodeBoundingBox)
+    }
+
     /**
      * Start barcode scanning by initializing the camera and barcode scanner.
      */
@@ -244,7 +284,7 @@ class MobileScanner(
             // Enable torch if provided
             camera!!.cameraControl.enableTorch(torch)
-            val resolution = preview!!.resolutionInfo!!.resolution
+            val resolution = analysis.resolutionInfo!!.resolution
             val portrait = camera!!.cameraInfo.sensorRotationDegrees % 180 == 0
             val width = resolution.width.toDouble()
             val height = resolution.height.toDouble()
--- a/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
View file @1003c48
+++ b/android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerPlugin.kt
View file @1003c48
@@ -25,12 +25,14 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
     private var analyzerResult: MethodChannel.Result? = null
-    private val callback: MobileScannerCallback = { barcodes: List<Map<String, Any?>>, image: ByteArray? ->
+    private val callback: MobileScannerCallback = { barcodes: List<Map<String, Any?>>, image: ByteArray?, width: Int?, height: Int? ->
         if (image != null) {
             barcodeHandler.publishEvent(mapOf(
                 "name" to "barcode",
                 "data" to barcodes,
-                "image" to image
+                "image" to image,
+                "width" to width!!.toDouble(),
+                "height" to height!!.toDouble()
             ))
         } else {
             barcodeHandler.publishEvent(mapOf(
@@ -77,6 +79,7 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
             "torch" -> toggleTorch(call, result)
             "stop" -> stop(result)
             "analyzeImage" -> analyzeImage(call, result)
+            "updateScanWindow" -> updateScanWindow(call)
             else -> result.notImplemented()
         }
     }
@@ -215,4 +218,8 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
             result.error("MobileScanner", "Called toggleTorch() while stopped!", null)
         }
     }
+
+    private fun updateScanWindow(call: MethodCall) {
+        handler!!.scanWindow = call.argument<List<Float>>("rect")
+    }
 }
--- a/example/ios/Runner.xcodeproj/project.pbxproj
View file @1003c48
+++ b/example/ios/Runner.xcodeproj/project.pbxproj
View file @1003c48
@@ -354,6 +354,8 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_IDENTITY = "Apple Development";
+				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = "$(FLUTTER_BUILD_NUMBER)";
 				DEVELOPMENT_TEAM = 75Y2P2WSQQ;
 				ENABLE_BITCODE = NO;
@@ -364,6 +366,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = dev.steenbakker.mobileScanner;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_VERSION = 5.0;
 				VERSIONING_SYSTEM = "apple-generic";
@@ -483,6 +486,8 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_IDENTITY = "Apple Development";
+				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = "$(FLUTTER_BUILD_NUMBER)";
 				DEVELOPMENT_TEAM = 75Y2P2WSQQ;
 				ENABLE_BITCODE = NO;
@@ -493,6 +498,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = dev.steenbakker.mobileScanner;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				SWIFT_VERSION = 5.0;
@@ -506,6 +512,8 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_ENABLE_MODULES = YES;
+				CODE_SIGN_IDENTITY = "Apple Development";
+				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = "$(FLUTTER_BUILD_NUMBER)";
 				DEVELOPMENT_TEAM = 75Y2P2WSQQ;
 				ENABLE_BITCODE = NO;
@@ -516,6 +524,7 @@
 				);
 				PRODUCT_BUNDLE_IDENTIFIER = dev.steenbakker.mobileScanner;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_VERSION = 5.0;
 				VERSIONING_SYSTEM = "apple-generic";
--- a/example/lib/barcode_scanner_window.dart 0 → 100644
View file @1003c48
+++ b/example/lib/barcode_scanner_window.dart 0 → 100644
View file @1003c48
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+
+class BarcodeScannerWithScanWindow extends StatefulWidget {
+  const BarcodeScannerWithScanWindow({Key? key}) : super(key: key);
+
+  @override
+  _BarcodeScannerWithScanWindowState createState() =>
+      _BarcodeScannerWithScanWindowState();
+}
+
+class _BarcodeScannerWithScanWindowState
+    extends State<BarcodeScannerWithScanWindow> {
+  late MobileScannerController controller = MobileScannerController();
+  Barcode? barcode;
+  BarcodeCapture? capture;
+
+  Future<void> onDetect(BarcodeCapture barcode) async {
+    capture = barcode;
+    setState(() => this.barcode = barcode.barcodes.first);
+  }
+
+  MobileScannerArguments? arguments;
+
+  @override
+  Widget build(BuildContext context) {
+    final scanWindow = Rect.fromCenter(
+      center: MediaQuery.of(context).size.center(Offset.zero),
+      width: 200,
+      height: 200,
+    );
+    return Scaffold(
+      backgroundColor: Colors.black,
+      body: Builder(
+        builder: (context) {
+          return Stack(
+            fit: StackFit.expand,
+            children: [
+              MobileScanner(
+                fit: BoxFit.contain,
+                scanWindow: scanWindow,
+                controller: controller,
+                onScannerStarted: (arguments) {
+                  setState(() {
+                    this.arguments = arguments;
+                  });
+                },
+                onDetect: onDetect,
+              ),
+              if (barcode != null &&
+                  barcode?.corners != null &&
+                  arguments != null)
+                CustomPaint(
+                  painter: BarcodeOverlay(
+                    barcode!,
+                    arguments!,
+                    BoxFit.contain,
+                    MediaQuery.of(context).devicePixelRatio,
+                    capture!,
+                  ),
+                ),
+              CustomPaint(
+                painter: ScannerOverlay(scanWindow),
+              ),
+              Align(
+                alignment: Alignment.bottomCenter,
+                child: Container(
+                  alignment: Alignment.bottomCenter,
+                  height: 100,
+                  color: Colors.black.withOpacity(0.4),
+                  child: Row(
+                    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                    children: [
+                      Center(
+                        child: SizedBox(
+                          width: MediaQuery.of(context).size.width - 120,
+                          height: 50,
+                          child: FittedBox(
+                            child: Text(
+                              barcode?.displayValue ?? 'Scan something!',
+                              overflow: TextOverflow.fade,
+                              style: Theme.of(context)
+                                  .textTheme
+                                  .headline4!
+                                  .copyWith(color: Colors.white),
+                            ),
+                          ),
+                        ),
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+}
+
+class ScannerOverlay extends CustomPainter {
+  ScannerOverlay(this.scanWindow);
+
+  final Rect scanWindow;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final backgroundPath = Path()..addRect(Rect.largest);
+    final cutoutPath = Path()..addRect(scanWindow);
+
+    final backgroundPaint = Paint()
+      ..color = Colors.black.withOpacity(0.5)
+      ..style = PaintingStyle.fill
+      ..blendMode = BlendMode.dstOut;
+
+    final backgroundWithCutout = Path.combine(
+      PathOperation.difference,
+      backgroundPath,
+      cutoutPath,
+    );
+    canvas.drawPath(backgroundWithCutout, backgroundPaint);
+  }
+
+  @override
+  bool shouldRepaint(covariant CustomPainter oldDelegate) {
+    return false;
+  }
+}
+
+class BarcodeOverlay extends CustomPainter {
+  BarcodeOverlay(
+    this.barcode,
+    this.arguments,
+    this.boxFit,
+    this.devicePixelRatio,
+    this.capture,
+  );
+
+  final BarcodeCapture capture;
+  final Barcode barcode;
+  final MobileScannerArguments arguments;
+  final BoxFit boxFit;
+  final double devicePixelRatio;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    if (barcode.corners == null) return;
+    final adjustedSize = applyBoxFit(boxFit, arguments.size, size);
+
+    double verticalPadding = size.height - adjustedSize.destination.height;
+    double horizontalPadding = size.width - adjustedSize.destination.width;
+    if (verticalPadding > 0) {
+      verticalPadding = verticalPadding / 2;
+    } else {
+      verticalPadding = 0;
+    }
+
+    if (horizontalPadding > 0) {
+      horizontalPadding = horizontalPadding / 2;
+    } else {
+      horizontalPadding = 0;
+    }
+
+    final ratioWidth =
+        (Platform.isIOS ? capture.width! : arguments.size.width) /
+            adjustedSize.destination.width;
+    final ratioHeight =
+        (Platform.isIOS ? capture.height! : arguments.size.height) /
+            adjustedSize.destination.height;
+
+    final List<Offset> adjustedOffset = [];
+    for (final offset in barcode.corners!) {
+      adjustedOffset.add(
+        Offset(
+          offset.dx / ratioWidth + horizontalPadding,
+          offset.dy / ratioHeight + verticalPadding,
+        ),
+      );
+    }
+    final cutoutPath = Path()..addPolygon(adjustedOffset, true);
+
+    final backgroundPaint = Paint()
+      ..color = Colors.red.withOpacity(0.3)
+      ..style = PaintingStyle.fill
+      ..blendMode = BlendMode.dstOut;
+
+    canvas.drawPath(cutoutPath, backgroundPaint);
+  }
+
+  @override
+  bool shouldRepaint(covariant CustomPainter oldDelegate) {
+    return false;
+  }
+}
--- a/example/lib/main.dart
View file @1003c48
+++ b/example/lib/main.dart
View file @1003c48
@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:mobile_scanner_example/barcode_list_scanner_controller.dart';
 import 'package:mobile_scanner_example/barcode_scanner_controller.dart';
 import 'package:mobile_scanner_example/barcode_scanner_returning_image.dart';
+import 'package:mobile_scanner_example/barcode_scanner_window.dart';
 import 'package:mobile_scanner_example/barcode_scanner_without_controller.dart';
 void main() => runApp(const MaterialApp(home: MyHome()));
@@ -44,6 +45,16 @@ class MyHome extends StatelessWidget {
               onPressed: () {
                 Navigator.of(context).push(
                   MaterialPageRoute(
+                    builder: (context) => const BarcodeScannerWithScanWindow(),
+                  ),
+                );
+              },
+              child: const Text('MobileScanner with ScanWindow'),
+            ),
+            ElevatedButton(
+              onPressed: () {
+                Navigator.of(context).push(
+                  MaterialPageRoute(
                     builder: (context) => const BarcodeScannerReturningImage(),
                   ),
                 );
--- a/ios/Classes/SwiftMobileScannerPlugin.swift
View file @1003c48
+++ b/ios/Classes/SwiftMobileScannerPlugin.swift
View file @1003c48
@@ -2,6 +2,7 @@ import Flutter
 import MLKitVision
 import MLKitBarcodeScanning
 import AVFoundation
+import UIKit
 public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
@@ -11,14 +12,45 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
     /// The handler sends all information via an event channel back to Flutter
     private let barcodeHandler: BarcodeHandler
+    static var scanWindow: [CGFloat]?
+    
+    private static func isBarcodeInScanWindow(barcode: Barcode, imageSize: CGSize) -> Bool {
+        let scanwindow = SwiftMobileScannerPlugin.scanWindow!
+        let barcodeminX = barcode.cornerPoints![0].cgPointValue.x
+        let barcodeminY = barcode.cornerPoints![1].cgPointValue.y
+        
+        let barcodewidth = barcode.cornerPoints![2].cgPointValue.x - barcodeminX
+        let barcodeheight = barcode.cornerPoints![3].cgPointValue.y - barcodeminY
+        let barcodeBox = CGRect(x: barcodeminX, y: barcodeminY, width: barcodewidth, height: barcodeheight)
+
+        
+        let minX = scanwindow[0] * imageSize.width
+        let minY = scanwindow[1] * imageSize.height
+
+        let width = (scanwindow[2] * imageSize.width)  - minX
+        let height = (scanwindow[3] * imageSize.height) - minY
+
+        let scaledWindow =  CGRect(x: minX, y: minY, width: width, height: height)
+        
+        return scaledWindow.contains(barcodeBox)
+    }
+    
     init(barcodeHandler: BarcodeHandler, registry: FlutterTextureRegistry) {
         self.mobileScanner = MobileScanner(registry: registry, mobileScannerCallback: { barcodes, error, image in
             if barcodes != nil {
-                let barcodesMap = barcodes!.map { barcode in
+                let barcodesMap = barcodes!.compactMap { barcode in
+                    if (SwiftMobileScannerPlugin.scanWindow != nil) {
+                        if (SwiftMobileScannerPlugin.isBarcodeInScanWindow(barcode: barcode, imageSize: image.size)) {
                             return barcode.data
+                        } else {
+                            return nil
+                        }
+                    } else {
+                        return barcode.data
+                    }
                 }
                 if (!barcodesMap.isEmpty) {
-                    barcodeHandler.publishEvent(["name": "barcode", "data": barcodesMap, "image": FlutterStandardTypedData(bytes: image.jpegData(compressionQuality: 0.8)!)])
+                    barcodeHandler.publishEvent(["name": "barcode", "data": barcodesMap, "image": FlutterStandardTypedData(bytes: image.jpegData(compressionQuality: 0.8)!), "width": image.size.width, "height": image.size.height])
                 }
             } else if (error != nil){
                 barcodeHandler.publishEvent(["name": "error", "data": error!.localizedDescription])
@@ -49,6 +81,8 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
             toggleTorch(call, result)
         case "analyzeImage":
             analyzeImage(call, result)
+        case "updateScanWindow":
+            updateScanWindow(call, result)
         default:
             result(FlutterMethodNotImplemented)
         }
@@ -123,6 +157,28 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
         result(nil)
     }
+    /// Toggles the torch
+    func updateScanWindow(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
+        let scanWindowData: Array? = (call.arguments as? [String: Any])?["rect"] as? [CGFloat]
+        SwiftMobileScannerPlugin.scanWindow = scanWindowData
+
+        result(nil)
+    }
+    
+    static func arrayToRect(scanWindowData: [CGFloat]?) -> CGRect? {
+        if (scanWindowData == nil) {
+            return nil
+        }
+
+        let minX = scanWindowData![0]
+        let minY = scanWindowData![1]
+
+        let width = scanWindowData![2]  - minX
+        let height = scanWindowData![3] - minY
+
+        return CGRect(x: minX, y: minY, width: width, height: height)
+    }
+    
     /// Analyzes a single image
     private func analyzeImage(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         let uiImage = UIImage(contentsOfFile: call.arguments as? String ?? "")
--- a/lib/src/barcode_utility.dart
View file @1003c48
+++ b/lib/src/barcode_utility.dart
View file @1003c48
+import 'dart:math' as math;
+
 import 'package:flutter/material.dart';
 import 'package:mobile_scanner/mobile_scanner.dart';
@@ -147,3 +149,79 @@ WiFi? toWiFi(Map? data) {
     return null;
   }
 }
+
+Size applyBoxFit(BoxFit fit, Size input, Size output) {
+  if (input.height <= 0.0 ||
+      input.width <= 0.0 ||
+      output.height <= 0.0 ||
+      output.width <= 0.0) {
+    return Size.zero;
+  }
+
+  Size destination;
+
+  final inputAspectRatio = input.width / input.height;
+  final outputAspectRatio = output.width / output.height;
+
+  switch (fit) {
+    case BoxFit.fill:
+      destination = output;
+      break;
+    case BoxFit.contain:
+      if (outputAspectRatio > inputAspectRatio) {
+        destination = Size(
+          input.width * output.height / input.height,
+          output.height,
+        );
+      } else {
+        destination = Size(
+          output.width,
+          input.height * output.width / input.width,
+        );
+      }
+      break;
+
+    case BoxFit.cover:
+      if (outputAspectRatio > inputAspectRatio) {
+        destination = Size(
+          output.width,
+          input.height * (output.width / input.width),
+        );
+      } else {
+        destination = Size(
+          input.width * (output.height / input.height),
+          output.height,
+        );
+      }
+      break;
+    case BoxFit.fitWidth:
+      destination = Size(
+        output.width,
+        input.height * (output.width / input.width),
+      );
+      break;
+    case BoxFit.fitHeight:
+      destination = Size(
+        input.width * (output.height / input.height),
+        output.height,
+      );
+      break;
+    case BoxFit.none:
+      destination = Size(
+        math.min(input.width, output.width),
+        math.min(input.height, output.height),
+      );
+      break;
+    case BoxFit.scaleDown:
+      destination = input;
+      if (destination.height > output.height) {
+        destination = Size(output.height * inputAspectRatio, output.height);
+      }
+      if (destination.width > output.width) {
+        destination = Size(output.width, output.width / inputAspectRatio);
+      }
+      break;
+  }
+
+  return destination;
+}
--- a/lib/src/mobile_scanner.dart
View file @1003c48
+++ b/lib/src/mobile_scanner.dart
View file @1003c48
@@ -34,6 +34,13 @@ class MobileScanner extends StatefulWidget {
   /// If this is null, a black [ColoredBox] is used as placeholder.
   final Widget Function(BuildContext, Widget?)? placeholderBuilder;
+  /// if set barcodes will only be scanned if they fall within this [Rect]
+  /// useful for having a cut-out overlay for example. these [Rect]
+  /// coordinates are relative to the widget size, so by how much your
+  /// rectangle overlays the actual image can depend on things like the
+  /// [BoxFit]
+  final Rect? scanWindow;
+
   /// Create a new [MobileScanner] using the provided [controller]
   /// and [onBarcodeDetected] callback.
   const MobileScanner({
@@ -43,6 +50,7 @@ class MobileScanner extends StatefulWidget {
     @Deprecated('Use onScannerStarted() instead.') this.onStart,
     this.onScannerStarted,
     this.placeholderBuilder,
+    this.scanWindow,
     super.key,
   });
@@ -117,8 +125,64 @@ class _MobileScannerState extends State<MobileScanner>
     }
   }
+  /// the [scanWindow] rect will be relative and scaled to the [widgetSize] not the texture. so it is possible,
+  /// depending on the [fit], for the [scanWindow] to partially or not at all overlap the [textureSize]
+  ///
+  /// since when using a [BoxFit] the content will always be centered on its parent. we can convert the rect
+  /// to be relative to the texture.
+  ///
+  /// since the textures size and the actuall image (on the texture size) might not be the same, we also need to
+  /// calculate the scanWindow in terms of percentages of the texture, not pixels.
+  Rect calculateScanWindowRelativeToTextureInPercentage(
+    BoxFit fit,
+    Rect scanWindow,
+    Size textureSize,
+    Size widgetSize,
+  ) {
+    /// map the texture size to get its new size after fitted to screen
+    final fittedTextureSize = applyBoxFit(fit, textureSize, widgetSize);
+
+    /// create a new rectangle that represents the texture on the screen
+    final minX = widgetSize.width / 2 - fittedTextureSize.destination.width / 2;
+    final minY =
+        widgetSize.height / 2 - fittedTextureSize.destination.height / 2;
+    final textureWindow = Offset(minX, minY) & fittedTextureSize.destination;
+
+    /// create a new scan window and with only the area of the rect intersecting the texture window
+    final scanWindowInTexture = scanWindow.intersect(textureWindow);
+
+    /// update the scanWindow left and top to be relative to the texture not the widget
+    final newLeft = scanWindowInTexture.left - textureWindow.left;
+    final newTop = scanWindowInTexture.top - textureWindow.top;
+    final newWidth = scanWindowInTexture.width;
+    final newHeight = scanWindowInTexture.height;
+
+    /// new scanWindow that is adapted to the boxfit and relative to the texture
+    final windowInTexture = Rect.fromLTWH(newLeft, newTop, newWidth, newHeight);
+
+    /// get the scanWindow as a percentage of the texture
+    final percentageLeft =
+        windowInTexture.left / fittedTextureSize.destination.width;
+    final percentageTop =
+        windowInTexture.top / fittedTextureSize.destination.height;
+    final percentageRight =
+        windowInTexture.right / fittedTextureSize.destination.width;
+    final percentagebottom =
+        windowInTexture.bottom / fittedTextureSize.destination.height;
+
+    /// this rectangle can be send to native code and used to cut out a rectangle of the scan image
+    return Rect.fromLTRB(
+      percentageLeft,
+      percentageTop,
+      percentageRight,
+      percentagebottom,
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
+    return LayoutBuilder(
+      builder: (context, constraints) {
         return ValueListenableBuilder<MobileScannerArguments?>(
           valueListenable: _controller.startArguments,
           builder: (context, value, child) {
@@ -127,6 +191,16 @@ class _MobileScannerState extends State<MobileScanner>
                   const ColoredBox(color: Colors.black);
             }
+            if (widget.scanWindow != null) {
+              final window = calculateScanWindowRelativeToTextureInPercentage(
+                widget.fit,
+                widget.scanWindow!,
+                value.size,
+                Size(constraints.maxWidth, constraints.maxHeight),
+              );
+              _controller.updateScanWindow(window);
+            }
+
             return ClipRect(
               child: LayoutBuilder(
                 builder: (_, constraints) {
@@ -148,6 +222,8 @@ class _MobileScannerState extends State<MobileScanner>
             );
           },
         );
+      },
+    );
   }
   @override
--- a/lib/src/mobile_scanner_controller.dart
View file @1003c48
+++ b/lib/src/mobile_scanner_controller.dart
View file @1003c48
@@ -126,6 +126,15 @@ class MobileScannerController {
     arguments['speed'] = detectionSpeed.index;
     arguments['timeout'] = detectionTimeoutMs;
+    /*    if (scanWindow != null) {
+      arguments['scanWindow'] = [
+        scanWindow!.left,
+        scanWindow!.top,
+        scanWindow!.right,
+        scanWindow!.bottom,
+      ];
+    } */
+
     if (formats != null) {
       if (Platform.isAndroid) {
         arguments['formats'] = formats!.map((e) => e.index).toList();
@@ -317,6 +326,8 @@ class MobileScannerController {
           BarcodeCapture(
             barcodes: parsed,
             image: event['image'] as Uint8List?,
+            width: event['width'] as double?,
+            height: event['height'] as double?,
           ),
         );
         break;
@@ -353,4 +364,10 @@ class MobileScannerController {
         throw UnimplementedError(name as String?);
     }
   }
+
+  /// updates the native scanwindow
+  Future<void> updateScanWindow(Rect window) async {
+    final data = [window.left, window.top, window.right, window.bottom];
+    await _methodChannel.invokeMethod('updateScanWindow', {'rect': data});
+  }
 }
--- a/lib/src/objects/barcode_capture.dart
View file @1003c48
+++ b/lib/src/objects/barcode_capture.dart
View file @1003c48
@@ -12,8 +12,14 @@ class BarcodeCapture {
   final Uint8List? image;
+  final double? width;
+
+  final double? height;
+
   BarcodeCapture({
     required this.barcodes,
     this.image,
+    this.width,
+    this.height,
   });
 }
--- a/macos/Classes/MobileScannerPlugin.swift
View file @1003c48
+++ b/macos/Classes/MobileScannerPlugin.swift
View file @1003c48
 import AVFoundation
 import FlutterMacOS
 import Vision
+import UIKit
 public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler, FlutterTexture, AVCaptureVideoDataOutputSampleBufferDelegate {
@@ -21,6 +22,9 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
     // Image to be sent to the texture
     var latestBuffer: CVImageBuffer!
+    // optional window to limit scan search
+    var scanWindow: CGRect?
+    
 //    var analyzeMode: Int = 0
     var analyzing: Bool = false
@@ -57,6 +61,8 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
 //            switchAnalyzeMode(call, result)
         case "stop":
             stop(result)
+        case "updateScanWindow":
+            updateScanWindow(call)
         default:
             result(FlutterMethodNotImplemented)
         }
@@ -110,6 +116,13 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
                   if error == nil {
                       if let results = request.results as? [VNBarcodeObservation] {
                             for barcode in results {
+                                if scanWindow != nil {
+                                    let match = isbarCodeInScanWindow(scanWindow!, barcode, buffer!.image)
+                                    if (!match) {
+                                        continue
+                                    }
+                                }
+
                                 let barcodeType = String(barcode.symbology.rawValue).replacingOccurrences(of: "VNBarcodeSymbology", with: "")
                                 let event: [String: Any?] = ["name": "barcodeMac", "data" : ["payload": barcode.payloadStringValue, "symbology": barcodeType]]
                                 self.sink?(event)
@@ -158,6 +171,38 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
         }
     }
+    func updateScanWindow(_ call: FlutterMethodCall) {
+        let argReader = MapArgumentReader(call.arguments as? [String: Any])
+        let scanWindowData: Array? = argReader.floatArray(key: "rect")
+
+        if (scanWindowData == nil) {
+            return 
+        }
+
+        let minX = scanWindowData![0] 
+        let minY = scanWindowData![1]
+
+        let width = scanWindowData![2]  - minX
+        let height = scanWindowData![3] - minY
+
+        scanWindow = CGRect(x: minX, y: minY, width: width, height: height)
+    }
+
+   func isbarCodeInScanWindow(_ scanWindow: CGRect, _ barcode: Barcode, _ inputImage: UIImage) -> Bool {
+        let barcodeBoundingBox = barcode.frame
+
+        let imageWidth = inputImage.size.width;
+        let imageHeight = inputImage.size.height;
+
+        let minX = scanWindow.minX * imageWidth
+        let minY = scanWindow.minY * imageHeight
+        let width = scanWindow.width * imageWidth
+        let height = scanWindow.height * imageHeight
+
+        let scaledScanWindow = CGRect(x: minX, y: minY, width: width, height: height)
+        return scaledScanWindow.contains(barcodeBoundingBox)
+    }
+
     func start(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         if (device != nil) {
             result(FlutterError(code: "MobileScanner",
@@ -319,4 +364,8 @@ class MapArgumentReader {
     return args?[key] as? [String]
   }
+  func floatArray(key: String) -> [CGFloat]? {
+    return args?[key] as? [CGFloat]
+  }
+  
 }