Merge pull request #383 from OrangeSofter/correct_scan_area_size

Correct scan area size on android

android/src/main/kotlin/net/touchcapture/qr/flutterqr/CustomFramingRectBarcodeView.java

@@ -0,0 +1,50 @@
+package net.touchcapture.qr.flutterqr;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.util.AttributeSet;
+
+import com.journeyapps.barcodescanner.BarcodeView;
+import com.journeyapps.barcodescanner.Size;
+
+public class CustomFramingRectBarcodeView extends BarcodeView {
+
+    private static final int BOTTOM_OFFSET_NOT_SET_VALUE = -1;
+
+    private int bottomOffset = BOTTOM_OFFSET_NOT_SET_VALUE;
+
+    public CustomFramingRectBarcodeView(Context context) {
+        super(context);
+    }
+
+    public CustomFramingRectBarcodeView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public CustomFramingRectBarcodeView(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    @Override
+    protected Rect calculateFramingRect(Rect container, Rect surface) {
+        Rect containerArea = new Rect(container);
+        boolean intersects = containerArea.intersect(surface);//adjusts the containerArea (code from super.calculateFramingRect)
+        Rect scanAreaRect = super.calculateFramingRect(container, surface);
+        if (bottomOffset != BOTTOM_OFFSET_NOT_SET_VALUE) {//if the setFramingRect function was called, then we shift the scan area by Y
+            Rect scanAreaRectWithOffset = new Rect(scanAreaRect);
+            scanAreaRectWithOffset.bottom -= bottomOffset;
+            scanAreaRectWithOffset.top -= bottomOffset;
+
+            boolean belongsToContainer = scanAreaRectWithOffset.intersect(containerArea);
+            if(belongsToContainer){
+                return scanAreaRectWithOffset;
+            }
+        }
+        return scanAreaRect;
+    }
+
+    public void setFramingRect(int rectWidth, int rectHeight, int bottomOffset) {
+        this.bottomOffset = bottomOffset;
+        this.setFramingRectSize(new Size(rectWidth, rectHeight));
+    }
+}

android/src/main/kotlin/net/touchcapture/qr/flutterqr/QRView.kt

@@ -3,6 +3,7 @@ package net.touchcapture.qr.flutterqr
 import android.Manifest
 import android.app.Activity
 import android.app.Application
+import android.content.Context
 import android.content.pm.PackageManager
 import android.hardware.Camera.CameraInfo
 import android.os.Build
@@ -12,7 +13,6 @@ import com.google.zxing.BarcodeFormat
 import com.google.zxing.ResultPoint
 import com.journeyapps.barcodescanner.BarcodeCallback
 import com.journeyapps.barcodescanner.BarcodeResult
-import com.journeyapps.barcodescanner.BarcodeView
 import io.flutter.plugin.common.BinaryMessenger
 import io.flutter.plugin.common.MethodCall
 import io.flutter.plugin.common.MethodChannel
@@ -20,12 +20,12 @@ import io.flutter.plugin.common.PluginRegistry
 import io.flutter.plugin.platform.PlatformView
 
 
-class QRView(messenger: BinaryMessenger,private val id: Int, private val params: HashMap<String, Any>) :
+class QRView(private val context: Context, messenger: BinaryMessenger, private val id: Int, private val params: HashMap<String, Any>) :
         PlatformView, MethodChannel.MethodCallHandler, PluginRegistry.RequestPermissionsResultListener {
 
     private var isTorchOn: Boolean = false
     private var isPaused: Boolean = false
-    private var barcodeView: BarcodeView? = null
+    private var barcodeView: CustomFramingRectBarcodeView? = null
     private val channel: MethodChannel = MethodChannel(messenger, "net.touchcapture.qr.flutterqr/qrview_$id")
     private var permissionGranted: Boolean = false
 
@@ -88,6 +88,11 @@ class QRView(messenger: BinaryMessenger,private val id: Int, private val params:
             "getCameraInfo" -> getCameraInfo(result)
             "getFlashInfo" -> getFlashInfo(result)
             "getSystemFeatures" -> getSystemFeatures(result)
+            "changeScanArea" -> changeScanArea(
+                call.argument<Double>("cutOutSize")!!,
+                call.argument<Double>("cutOutBottomOffset")!!,
+                result,
+            )
             else -> result.notImplemented()
         }
     }
@@ -190,9 +195,10 @@ class QRView(messenger: BinaryMessenger,private val id: Int, private val params:
         return initBarCodeView().apply {}!!
     }
 
-    private fun initBarCodeView(): BarcodeView? {
+    private fun initBarCodeView(): CustomFramingRectBarcodeView? {
         if (barcodeView == null) {
-            barcodeView = BarcodeView(Shared.activity)
+            barcodeView =
+                CustomFramingRectBarcodeView(Shared.activity)
             if (params["cameraFacing"] as Int == 1) {
                 barcodeView?.cameraSettings?.requestedCameraId = CameraInfo.CAMERA_FACING_FRONT
             }
@@ -246,6 +252,30 @@ class QRView(messenger: BinaryMessenger,private val id: Int, private val params:
         }
     }
 
+    private fun changeScanArea(
+        cutOutSize: Double,
+        cutOutBottomOffset: Double,
+        result: MethodChannel.Result
+    ) {
+        setScanAreaSize(cutOutSize, cutOutSize, cutOutBottomOffset)
+        result.success(true)
+    }
+
+    private fun setScanAreaSize(
+        dpScanAreaWidth: Double,
+        dpScanAreaHeight: Double,
+        dpCutOutBottomOffset: Double
+    ) {
+        barcodeView?.setFramingRect(
+            convertDpToPixels(dpScanAreaWidth),
+            convertDpToPixels(dpScanAreaHeight),
+            convertDpToPixels(dpCutOutBottomOffset),
+        )
+    }
+
+    private fun convertDpToPixels(dp: Double) =
+        (dp * context.resources.displayMetrics.density).toInt()
+
     private fun hasCameraPermission(): Boolean {
         return permissionGranted ||
                 Build.VERSION.SDK_INT < Build.VERSION_CODES.M ||

android/src/main/kotlin/net/touchcapture/qr/flutterqr/QRViewFactory.kt

@@ -12,7 +12,7 @@ class QRViewFactory(private val messenger: BinaryMessenger) :
 
     override fun create(context: Context, id: Int, args: Any?): PlatformView {
         val params = args as HashMap<String, Any>
-        return QRView(messenger, id, params)
+        return QRView(context, messenger, id, params)
     }
 
 }

lib/src/qr_code_scanner.dart

@@ -341,6 +341,15 @@ class QRViewController {
       } on PlatformException catch (e) {
         throw CameraException(e.code, e.message);
       }
+    } else if (defaultTargetPlatform == TargetPlatform.android) {
+      if (overlay == null) {
+        return false;
+      }
+      await channel.invokeMethod('changeScanArea', {
+        'cutOutSize': overlay.cutOutSize,
+        'cutOutBottomOffset': overlay.cutOutBottomOffset
+      });
+      return true;
     }
     return false;
   }