Merge pull request #29074 from varun-jaiswal17:data-layout-wrapper-java

Add missing DataLayout constants in generated bindings for 5.x #29074

- Added DATA_LAYOUT_* constants to missing_consts so they
  are manually injected into Core.java (same approach used for CV_8U, FILLED etc.)
- Added DataLayout entry to type_dict so the generator correctly maps
  DataLayout 

### Tests

modules/dnn/misc/java/test/DnnBlobFromImageWithParamsTest.java:

New test added:
- testDataLayoutConstants: verifies all DATA_LAYOUT_*  constants are accessible from Core
  
Pre-existing tests enabled (were commented out earlier):
- testBlobFromImageWithParamsNHWCScalarScale: verifies blobFromImageWithParams
  produces correct output with DATA_LAYOUT_NHWC and per-channel scalar scaling
- testBlobFromImageWithParams4chMultiImage: verifies blobFromImagesWithParams
  correctly handles a batch of images with DATA_LAYOUT_NHWC layout
  
Closes : #27264 

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/core/misc/java/gen_dict.json

@@ -20,7 +20,10 @@
             "public" : [
                 ["SVD_MODIFY_A", 1], ["SVD_NO_UV", 2], ["SVD_FULL_UV", 4],
                 ["FILLED", -1],
-                ["REDUCE_SUM", 0], ["REDUCE_AVG", 1], ["REDUCE_MAX", 2], ["REDUCE_MIN", 3]
+                ["REDUCE_SUM", 0], ["REDUCE_AVG", 1], ["REDUCE_MAX", 2], ["REDUCE_MIN", 3],
+                ["DATA_LAYOUT_UNKNOWN", 0], ["DATA_LAYOUT_ND", 1], ["DATA_LAYOUT_NCHW", 2],
+                ["DATA_LAYOUT_NCDHW", 3], ["DATA_LAYOUT_NHWC", 4], ["DATA_LAYOUT_NDHWC", 5],
+                ["DATA_LAYOUT_PLANAR", 6], ["DATA_LAYOUT_BLOCK", 7]
             ]
         }
     },
@@ -166,6 +169,14 @@
             "suffix": "II",
             "j_import": "org.opencv.core.Range"
         },
+        "DataLayout": {
+            "cast_from": "int",
+            "cast_to": "cv::DataLayout",
+            "j_type": "int",
+            "jn_type": "int",
+            "jni_type": "jint",
+            "suffix": "I"
+        },
         "CvTermCriteria": {
             "j_type": "TermCriteria",
             "jn_args": [

modules/dnn/misc/java/test/DnnBlobFromImageWithParamsTest.java

@@ -15,17 +15,28 @@ import org.opencv.test.OpenCVTestCase;
 
 public class DnnBlobFromImageWithParamsTest extends OpenCVTestCase {
 
+        // test for DATA_LAYOUT_* and DNN_LAYOUT_* access from Core
+        public void testDataLayoutConstants()
+        {
+            assertEquals(0, Core.DATA_LAYOUT_UNKNOWN);
+            assertEquals(1, Core.DATA_LAYOUT_ND);
+            assertEquals(2, Core.DATA_LAYOUT_NCHW);
+            assertEquals(3, Core.DATA_LAYOUT_NCDHW);
+            assertEquals(4, Core.DATA_LAYOUT_NHWC);
+            assertEquals(5, Core.DATA_LAYOUT_NDHWC);
+            assertEquals(6, Core.DATA_LAYOUT_PLANAR);
+            assertEquals(7, Core.DATA_LAYOUT_BLOCK);
+        }
+
         public void testBlobFromImageWithParamsNHWCScalarScale()
         {
             // https://github.com/opencv/opencv/issues/27264
-            /*
             Mat img = new Mat(10, 10, CvType.CV_8UC4, new Scalar(0, 1, 2, 3));
             Scalar scalefactor = new Scalar(0.1, 0.2, 0.3, 0.4);
 
             Image2BlobParams params = new Image2BlobParams();
             params.set_scalefactor(scalefactor);
             params.set_datalayout(Core.DATA_LAYOUT_NHWC);
-            return;
 
             Mat blob = Dnn.blobFromImageWithParams(img, params); // [1, 10, 10, 4]
 
@@ -43,7 +54,6 @@ public class DnnBlobFromImageWithParamsTest extends OpenCVTestCase {
                       }
                 }
             }
-            */
         }
 
         public void testBlobFromImageWithParamsCustomPaddingLetterBox()
@@ -105,7 +115,6 @@ public class DnnBlobFromImageWithParamsTest extends OpenCVTestCase {
         // https://github.com/opencv/opencv/issues/27264
         public void testBlobFromImageWithParams4chMultiImage()
         {
-            /*
             Mat img = new Mat(10, 10, CvType.CV_8UC4, new Scalar(0, 1, 2, 3));
 
             Scalar scalefactor = new Scalar(0.1, 0.2, 0.3, 0.4);
@@ -113,7 +122,6 @@ public class DnnBlobFromImageWithParamsTest extends OpenCVTestCase {
             Image2BlobParams param = new Image2BlobParams();
             param.set_scalefactor(scalefactor);
             param.set_datalayout(Core.DATA_LAYOUT_NHWC);
-            return;
 
             List<Mat> images = new ArrayList<>();
             images.add(img);
@@ -137,6 +145,5 @@ public class DnnBlobFromImageWithParamsTest extends OpenCVTestCase {
             Core.multiply(blob0, Scalar.all(2), blob0);
 
             assertEquals(0, Core.norm(blob0, blob1, Core.NORM_INF), EPS);
-            */
         }
 }