feat: add zoomScale api for android and iOS

@@ -33,6 +33,8 @@ class AlreadyStopped : Exception()
 class TorchError : Exception()
 class CameraError : Exception()
 class TorchWhenStopped : Exception()
+class ZoomWhenStopped : Exception()
+class ZoomNotInRange : Exception()
 
 class MobileScanner(
     private val activity: Activity,
@@ -312,4 +314,13 @@ class MobileScanner(
             }
     }
 
+    /**
+     * Set the zoom rate of the camera.
+     */
+    fun setScale(scale: Double) {
+        if (camera == null) throw ZoomWhenStopped()
+        if (scale > 1.0 || scale < 0) throw ZoomNotInRange()
+        camera!!.cameraControl.setLinearZoom(scale.toFloat())
+    }
+
 }

@@ -83,6 +83,7 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
             "torch" -> toggleTorch(call, result)
             "stop" -> stop(result)
             "analyzeImage" -> analyzeImage(call, result)
+            "setScale" -> setScale(call, result)
             else -> result.notImplemented()
         }
     }
@@ -226,4 +227,15 @@ class MobileScannerPlugin : FlutterPlugin, ActivityAware, MethodChannel.MethodCa
             result.error("MobileScanner", "Called toggleTorch() while stopped!", null)
         }
     }
+
+    private fun setScale(call: MethodCall, result: MethodChannel.Result) {
+        try {
+            handler!!.setScale(call.arguments as Double)
+            result.success(null)
+        } catch (e: ZoomWhenStopped) {
+            result.error("MobileScanner", "Called setScale() while stopped!", null)
+        } catch (e: ZoomNotInRange) {
+            result.error("MobileScanner", "Scale should be within 0 and 1", null)
+        }
+    }
 }

+import 'package:flutter/material.dart';
+import 'package:image_picker/image_picker.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+
+class BarcodeScannerWithZoom extends StatefulWidget {
+  const BarcodeScannerWithZoom({Key? key}) : super(key: key);
+
+  @override
+  _BarcodeScannerWithZoomState createState() => _BarcodeScannerWithZoomState();
+}
+
+class _BarcodeScannerWithZoomState extends State<BarcodeScannerWithZoom>
+    with SingleTickerProviderStateMixin {
+  BarcodeCapture? barcode;
+
+  MobileScannerController controller = MobileScannerController(
+    torchEnabled: true,
+    onPermissionSet: (hasPermission) {
+      // Do something with permission callback
+    },
+  );
+
+  bool isStarted = true;
+  double _zoomFactor = 0.0;
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      backgroundColor: Colors.black,
+      body: Builder(
+        builder: (context) {
+          return Stack(
+            children: [
+              MobileScanner(
+                controller: controller,
+                fit: BoxFit.contain,
+                onDetect: (barcode) {
+                  setState(() {
+                    this.barcode = barcode;
+                  });
+                },
+              ),
+              Align(
+                alignment: Alignment.bottomCenter,
+                child: Container(
+                  alignment: Alignment.bottomCenter,
+                  height: 100,
+                  color: Colors.black.withOpacity(0.4),
+                  child: Column(
+                    children: [
+                      Slider(
+                        value: _zoomFactor,
+                        onChanged: (value) {
+                          setState(() {
+                            _zoomFactor = value;
+                            controller.setZoomScale(value);
+                          });
+                        },
+                      ),
+                      Row(
+                        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                        children: [
+                          IconButton(
+                            color: Colors.white,
+                            icon: ValueListenableBuilder(
+                              valueListenable: controller.torchState,
+                              builder: (context, state, child) {
+                                if (state == null) {
+                                  return const Icon(
+                                    Icons.flash_off,
+                                    color: Colors.grey,
+                                  );
+                                }
+                                switch (state as TorchState) {
+                                  case TorchState.off:
+                                    return const Icon(
+                                      Icons.flash_off,
+                                      color: Colors.grey,
+                                    );
+                                  case TorchState.on:
+                                    return const Icon(
+                                      Icons.flash_on,
+                                      color: Colors.yellow,
+                                    );
+                                }
+                              },
+                            ),
+                            iconSize: 32.0,
+                            onPressed: () => controller.toggleTorch(),
+                          ),
+                          IconButton(
+                            color: Colors.white,
+                            icon: isStarted
+                                ? const Icon(Icons.stop)
+                                : const Icon(Icons.play_arrow),
+                            iconSize: 32.0,
+                            onPressed: () => setState(() {
+                              isStarted
+                                  ? controller.stop()
+                                  : controller.start();
+                              isStarted = !isStarted;
+                            }),
+                          ),
+                          Center(
+                            child: SizedBox(
+                              width: MediaQuery.of(context).size.width - 200,
+                              height: 50,
+                              child: FittedBox(
+                                child: Text(
+                                  barcode?.barcodes.first.rawValue ??
+                                      'Scan something!',
+                                  overflow: TextOverflow.fade,
+                                  style: Theme.of(context)
+                                      .textTheme
+                                      .headline4!
+                                      .copyWith(color: Colors.white),
+                                ),
+                              ),
+                            ),
+                          ),
+                          IconButton(
+                            color: Colors.white,
+                            icon: ValueListenableBuilder(
+                              valueListenable: controller.cameraFacingState,
+                              builder: (context, state, child) {
+                                if (state == null) {
+                                  return const Icon(Icons.camera_front);
+                                }
+                                switch (state as CameraFacing) {
+                                  case CameraFacing.front:
+                                    return const Icon(Icons.camera_front);
+                                  case CameraFacing.back:
+                                    return const Icon(Icons.camera_rear);
+                                }
+                              },
+                            ),
+                            iconSize: 32.0,
+                            onPressed: () => controller.switchCamera(),
+                          ),
+                          IconButton(
+                            color: Colors.white,
+                            icon: const Icon(Icons.image),
+                            iconSize: 32.0,
+                            onPressed: () async {
+                              final ImagePicker picker = ImagePicker();
+                              // Pick an image
+                              final XFile? image = await picker.pickImage(
+                                source: ImageSource.gallery,
+                              );
+                              if (image != null) {
+                                if (await controller.analyzeImage(image.path)) {
+                                  if (!mounted) return;
+                                  ScaffoldMessenger.of(context).showSnackBar(
+                                    const SnackBar(
+                                      content: Text('Barcode found!'),
+                                      backgroundColor: Colors.green,
+                                    ),
+                                  );
+                                } else {
+                                  if (!mounted) return;
+                                  ScaffoldMessenger.of(context).showSnackBar(
+                                    const SnackBar(
+                                      content: Text('No barcode found!'),
+                                      backgroundColor: Colors.red,
+                                    ),
+                                  );
+                                }
+                              }
+                            },
+                          ),
+                        ],
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
+          );
+        },
+      ),
+    );
+  }
+}

@@ -3,6 +3,7 @@ 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_without_controller.dart';
+import 'package:mobile_scanner_example/barcode_scanner_zoom.dart';
 
 void main() => runApp(const MaterialApp(home: MyHome()));
 
@@ -62,6 +63,16 @@ class MyHome extends StatelessWidget {
               },
               child: const Text('MobileScanner without Controller'),
             ),
+            ElevatedButton(
+              onPressed: () {
+                Navigator.of(context).push(
+                  MaterialPageRoute(
+                    builder: (context) => const BarcodeScannerWithZoom(),
+                  ),
+                );
+              },
+              child: const Text('MobileScanner with zoom slider'),
+            ),
           ],
         ),
       ),

@@ -207,6 +207,33 @@ public class MobileScanner: NSObject, AVCaptureVideoDataOutputSampleBufferDelega
         }
     }
     
+    /// Set the zoom factor of the camera
+    func setScale(_ scale: CGFloat) throws {
+        if (device == nil) {
+            throw MobileScannerError.torchWhenStopped
+        }
+        
+        do {
+            try device.lockForConfiguration()
+            var maxZoomFactor = device.activeFormat.videoMaxZoomFactor
+            
+            var actualScale = (scale * 4) + 1
+            
+            // Set maximum zoomrate of 5x
+            actualScale = min(5.0, actualScale)
+            
+            // Limit to max rate of camera
+            actualScale = min(maxZoomFactor, actualScale)
+            
+            // Limit to 1.0 scale
+            device.ramp(toVideoZoomFactor: actualScale, withRate: 5)
+            device.unlockForConfiguration()
+        } catch {
+            throw MobileScannerError.zoomError(error)
+        }
+        
+    }
+
     /// Analyze a single image
     func analyzeImage(image: UIImage, position: AVCaptureDevice.Position, callback: @escaping BarcodeScanningCallback) {
         let image = VisionImage(image: image)

@@ -13,5 +13,7 @@ enum MobileScannerError: Error {
     case torchError(_ error: Error)
     case cameraError(_ error: Error)
     case torchWhenStopped
+    case zoomWhenStopped
+    case zoomError(_ error: Error)
     case analyzerError(_ error: Error)
 }

@@ -49,6 +49,8 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
             toggleTorch(call, result)
         case "analyzeImage":
             analyzeImage(call, result)
+        case "setScale":
+            setScale(call, result)
         default:
             result(FlutterMethodNotImplemented)
         }
@@ -127,6 +129,33 @@ public class SwiftMobileScannerPlugin: NSObject, FlutterPlugin {
         result(nil)
     }
     
+    /// Toggles the zoomScale
+    private func setScale(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
+        var scale = call.arguments as? CGFloat
+        if (scale == nil) {
+            result(FlutterError(code: "MobileScanner",
+                                              message: "You must provide a scale when calling setScale!",
+                                              details: nil))
+            return
+        }
+        do {
+            try mobileScanner.setScale(scale!)
+        } catch MobileScannerError.zoomWhenStopped {
+            result(FlutterError(code: "MobileScanner",
+                                message: "Called setScale() while stopped!",
+                                details: nil))
+        } catch MobileScannerError.zoomError(let error) {
+            result(FlutterError(code: "MobileScanner",
+                                message: "Error while zooming.",
+                                details: error))
+        } catch {
+            result(FlutterError(code: "MobileScanner",
+                                message: "Error while zooming.",
+                                details: nil))
+        }
+        result(nil)
+    }
+    
     /// Analyzes a single image
     private func analyzeImage(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         let uiImage = UIImage(contentsOfFile: call.arguments as? String ?? "")

@@ -249,6 +249,19 @@ class MobileScannerController {
         .then<bool>((bool? value) => value ?? false);
   }
 
+  /// Set the zoomScale of the camera.
+  ///
+  /// [zoomScale] must be within 0.0 and 1.0, where 1.0 is the max zoom, and 0.0
+  /// is zoomed out.
+  Future<void> setZoomScale(double zoomScale) async {
+    if (zoomScale < 0 || zoomScale > 1) {
+      throw MobileScannerException(
+        'The zoomScale must be between 0 and 1.',
+      );
+    }
+    await _methodChannel.invokeMethod('setScale', zoomScale);
+  }
+
   /// Disposes the MobileScannerController and closes all listeners.
   ///
   /// If you call this, you cannot use this controller object anymore.