From 30fc9ed9ba7855a65d92120cc5dab9c65b94613a Mon Sep 17 00:00:00 2001
From: Dmitry Kurtaev <dmitry.kurtaev@gmail.com>
Date: Tue, 3 Jun 2025 11:37:31 +0300
Subject: [PATCH] Handle Java bindings

---
 modules/java/generator/gen_java.py            |  3 +
 .../objdetect/graphical_code_detector.hpp     |  4 --
 modules/objdetect/misc/java/gen_dict.json     | 58 +++++--------------
 3 files changed, 16 insertions(+), 49 deletions(-)

diff --git a/modules/java/generator/gen_java.py b/modules/java/generator/gen_java.py
index 0ffa5bd6ae..797863249d 100755
--- a/modules/java/generator/gen_java.py
+++ b/modules/java/generator/gen_java.py
@@ -1002,6 +1002,9 @@ class JavaWrapperGenerator(object):
                 ret = "return (jlong) _retval_;"
             elif type_dict[fi.ctype]["jni_type"] == "jdoubleArray":
                 ret = "return _da_retval_;"
+            elif "jni_var" in type_dict[ret_type]:
+                c_epilogue.append(type_dict[ret_type]["jni_var"] % {"n" : '_retval_'})
+                ret = f"return {type_dict[ret_type]['jni_name'] % {'n' : '_retval_'}};"
 
             # hack: replacing func call with property set/get
             name = fi.name
diff --git a/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp b/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp
index d30d42ce52..7d46c99443 100644
--- a/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp
+++ b/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp
@@ -78,10 +78,6 @@ public:
     CV_WRAP_AS(detectAndDecodeBytes) NativeByteArray detectAndDecode(InputArray img, OutputArray points = noArray(),
                                                                      OutputArray straight_code = noArray()) const;
     CV_WRAP_AS(decodeBytes) NativeByteArray decode(InputArray img, InputArray points, OutputArray straight_code = noArray()) const;
-    // CV_WRAP_AS(decodeBytesMulti) bool decodeMulti(InputArray img, InputArray points, CV_OUT std::vector<NativeByteArray>& decoded_info,
-    //                                               OutputArrayOfArrays straight_code = noArray()) const;
-    // CV_WRAP_AS(detectAndDecodeBytesMulti) bool detectAndDecodeMulti(InputArray img, CV_OUT std::vector<NativeByteArray>& decoded_info, OutputArray points = noArray(),
-    //                                                                 OutputArrayOfArrays straight_code = noArray()) const;
 #endif
 
     struct Impl;
diff --git a/modules/objdetect/misc/java/gen_dict.json b/modules/objdetect/misc/java/gen_dict.json
index 4e6139a9da..54e5d3af92 100644
--- a/modules/objdetect/misc/java/gen_dict.json
+++ b/modules/objdetect/misc/java/gen_dict.json
@@ -4,9 +4,9 @@
             "QRCodeEncoder" : {
                 "j_code"   : [
                     "\n",
-                    "/**",
-                    " * Constructor of streaming callback object with abstract 'read' and 'seek' methods that should be implemented in Java code.<br>",
-                    " * <b>NOTE</b>: Implemented callbacks should be called from the creation thread to avoid JNI performance degradation",
+                    "/** Generates QR code from input string.",
+                    "@param encoded_info Input bytes to encode.",
+                    "@param qrcode Generated QR code.",
                     "*/",
                     "public void encode(byte[] encoded_info, Mat qrcode) {",
                     "    encode_1(nativeObj, encoded_info, qrcode.nativeObj);",
@@ -45,48 +45,16 @@
                     "\n"
                 ]
             }
-        },
-        "GraphicalCodeDetector" : {
-            "GraphicalCodeDetector" : {
-                "j_code"   : [
-                    "\n",
-                    "public byte[] detectAndDecodeBytes(Mat img) {",
-                    "    return detectAndDecodeBytes_0(nativeObj, img.nativeObj);",
-                    "}",
-                    "\n"
-                ],
-                "jn_code": [
-                    "\n",
-                    "private static native byte[] detectAndDecodeBytes_0(long nativeObj, long img_nativeObj);",
-                    "\n"
-                ],
-                "cpp_code": [
-                    "JNIEXPORT jbyteArray JNICALL Java_org_opencv_objdetect_GraphicalCodeDetector_detectAndDecodeBytes_10 (JNIEnv*, jclass, jlong, jlong);",
-                    "\n",
-                    "JNIEXPORT jbyteArray JNICALL Java_org_opencv_objdetect_GraphicalCodeDetector_detectAndDecodeBytes_10",
-                    "  (JNIEnv* env, jclass , jlong self, jlong img_nativeObj)",
-                    "{",
-                    "    ",
-                    "    static const char method_name[] = \"objdetect::detectAndDecodeBytes_10()\";",
-                    "    try {",
-                    "        LOGD(\"%s\", method_name);",
-                    "        cv::GraphicalCodeDetector* me = (cv::GraphicalCodeDetector*) self; //TODO: check for NULL",
-                    "        Mat& img = *((Mat*)img_nativeObj);",
-                    "        std::string result = me->detectAndDecode( img );",
-                    "        jsize sz = result.size();",
-                    "        jbyteArray _retval_ = env->NewByteArray(static_cast<jsize>(sz));",
-                    "        env->SetByteArrayRegion(_retval_, 0, sz, reinterpret_cast<jbyte*>(&result[0]));",
-                    "        return _retval_;",
-                    "    } catch(const std::exception &e) {",
-                    "        throwJavaException(env, &e, method_name);",
-                    "    } catch (...) {",
-                    "        throwJavaException(env, 0, method_name);",
-                    "    }",
-                    "    return 0;",
-                    "}",
-                    "\n"
-                ]
-            }
+        }
+    },
+    "type_dict": {
+        "NativeByteArray": {
+            "j_type" : "byte[]",
+            "jn_type": "byte[]",
+            "jni_type": "jbyteArray",
+            "jni_name": "n_%(n)s",
+            "jni_var": "jbyteArray n_%(n)s = env->NewByteArray(static_cast<jsize>(%(n)s.size())); env->SetByteArrayRegion(n_%(n)s, 0, %(n)s.size(), reinterpret_cast<jbyte*>(&%(n)s[0]));",
+            "cast_from": "std::string"
         }
     }
 }