Merge pull request #24426 from dkurt:qrcode_eci_encoding

Consider QRCode ECI encoding #24426

### Pull Request Readiness Checklist

related: https://github.com/opencv/opencv/pull/24350#pullrequestreview-1661658421

1. Add `getEncoding` method to obtain ECI number
2. Add `detectAndDecodeBytes`, `decodeBytes`, `decodeBytesMulti`, `detectAndDecodeBytesMulti` methods in Python (return `bytes`) and Java (return `byte[]`)
3. Allow Python bytes to std::string conversion in general and add `encode(byte[] encoded_info, Mat qrcode)` in Java


    Python example with Kanji encoding:
    ```python
    img = cv.imread("test.png")
    detect = cv.QRCodeDetector()
    data, points, straight_qrcode = detect.detectAndDecodeBytes(img)
    print(data)
    print(detect.getEncoding(), cv.QRCodeEncoder_ECI_SHIFT_JIS)
    print(data.decode("shift-jis"))
    ```
    ```
    b'\x82\xb1\x82\xf1\x82\xc9\x82\xbf\x82\xcd\x90\xa2\x8aE'
    20 20
    こんにちは世界
    ```

    source: https://github.com/opencv/opencv/blob/ba4d6c859d21536f84e0328c16f4cc3e96bf3065/modules/objdetect/test/test_qrcode_encode.cpp#L332

    ![test](https://github.com/opencv/opencv/assets/25801568/0b5eefa8-918a-4c42-9acb-830f23c0ea9f)


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/objdetect/misc/java/filelist_common

@@ -0,0 +1 @@
+misc/java/src/cpp/objdetect_converters.hpp

modules/objdetect/misc/java/gen_dict.json

@@ -0,0 +1,68 @@
+{
+    "ManualFuncs" : {
+        "QRCodeEncoder" : {
+            "QRCodeEncoder" : {
+                "j_code"   : [
+                    "\n",
+                    "/** 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);",
+                    "}",
+                    "\n"
+                ],
+                "jn_code": [
+                    "\n",
+                    "private static native void encode_1(long nativeObj, byte[] encoded_info, long qrcode_nativeObj);",
+                    "\n"
+                ],
+                "cpp_code": [
+                    "//",
+                    "//  void cv::QRCodeEncoder::encode(String encoded_info, Mat& qrcode)",
+                    "//",
+                    "\n",
+                    "JNIEXPORT void JNICALL Java_org_opencv_objdetect_QRCodeEncoder_encode_11 (JNIEnv*, jclass, jlong, jbyteArray, jlong);",
+                    "\n",
+                    "JNIEXPORT void JNICALL Java_org_opencv_objdetect_QRCodeEncoder_encode_11",
+                    "(JNIEnv* env, jclass , jlong self, jbyteArray encoded_info, jlong qrcode_nativeObj)",
+                    "{",
+                    "",
+                    "    static const char method_name[] = \"objdetect::encode_11()\";",
+                    "    try {",
+                    "        LOGD(\"%s\", method_name);",
+                    "        Ptr<cv::QRCodeEncoder>* me = (Ptr<cv::QRCodeEncoder>*) self; //TODO: check for NULL",
+                    "        const char* n_encoded_info = reinterpret_cast<char*>(env->GetByteArrayElements(encoded_info, NULL));",
+                    "        Mat& qrcode = *((Mat*)qrcode_nativeObj);",
+                    "        (*me)->encode( n_encoded_info, qrcode );",
+                    "    } catch(const std::exception &e) {",
+                    "        throwJavaException(env, &e, method_name);",
+                    "    } catch (...) {",
+                    "        throwJavaException(env, 0, method_name);",
+                    "    }",
+                    "}",
+                    "\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, static_cast<jsize>(%(n)s.size()), reinterpret_cast<const jbyte*>(%(n)s.c_str()));",
+            "cast_from": "std::string"
+        },
+        "vector_NativeByteArray": {
+            "j_type": "List<byte[]>",
+            "jn_type": "List<byte[]>",
+            "jni_type": "jobject",
+            "jni_var": "std::vector< std::string > %(n)s",
+            "suffix": "Ljava_util_List",
+            "v_type": "vector_NativeByteArray"
+        }
+    }
+}

modules/objdetect/misc/java/src/cpp/objdetect_converters.cpp

@@ -0,0 +1,20 @@
+#include "objdetect_converters.hpp"
+
+#define LOG_TAG "org.opencv.objdetect"
+
+void Copy_vector_NativeByteArray_to_List(JNIEnv* env, std::vector<std::string>& vs, jobject list)
+{
+    static jclass juArrayList       = ARRAYLIST(env);
+    jmethodID m_clear     = LIST_CLEAR(env, juArrayList);
+    jmethodID m_add       = LIST_ADD(env, juArrayList);
+
+    env->CallVoidMethod(list, m_clear);
+    for (std::vector<std::string>::iterator it = vs.begin(); it != vs.end(); ++it)
+    {
+        jsize sz = static_cast<jsize>((*it).size());
+        jbyteArray element = env->NewByteArray(sz);
+        env->SetByteArrayRegion(element, 0, sz, reinterpret_cast<const jbyte*>((*it).c_str()));
+        env->CallBooleanMethod(list, m_add, element);
+        env->DeleteLocalRef(element);
+    }
+}

modules/objdetect/misc/java/src/cpp/objdetect_converters.hpp

@@ -0,0 +1,14 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html
+
+#ifndef OBJDETECT_CONVERTERS_HPP
+#define	OBJDETECT_CONVERTERS_HPP
+
+#include <jni.h>
+#include "opencv_java.hpp"
+#include "opencv2/core.hpp"
+
+void Copy_vector_NativeByteArray_to_List(JNIEnv* env, std::vector<std::string>& vs, jobject list);
+
+#endif	/* OBJDETECT_CONVERTERS_HPP */

modules/objdetect/misc/java/test/QRCodeDetectorTest.java

@@ -2,13 +2,19 @@ package org.opencv.test.objdetect;
 
 import java.util.List;
 import org.opencv.core.Mat;
+import org.opencv.core.Size;
 import org.opencv.objdetect.QRCodeDetector;
+import org.opencv.objdetect.QRCodeEncoder;
+import org.opencv.objdetect.QRCodeEncoder_Params;
 import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
 import org.opencv.test.OpenCVTestCase;
 import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
 
 public class QRCodeDetectorTest extends OpenCVTestCase {
 
@@ -50,4 +56,26 @@ public class QRCodeDetectorTest extends OpenCVTestCase {
         List < String > expectedResults = Arrays.asList("SKIP", "EXTRA", "TWO STEPS FORWARD", "STEP BACK", "QUESTION", "STEP FORWARD");
         assertEquals(new HashSet<String>(output), new HashSet<String>(expectedResults));
     }
+
+    public void testKanji() {
+        byte[] inp = new byte[]{(byte)0x82, (byte)0xb1, (byte)0x82, (byte)0xf1, (byte)0x82, (byte)0xc9, (byte)0x82,
+                                (byte)0xbf, (byte)0x82, (byte)0xcd, (byte)0x90, (byte)0xa2, (byte)0x8a, (byte)0x45};
+        QRCodeEncoder_Params params = new QRCodeEncoder_Params();
+        params.set_mode(QRCodeEncoder.MODE_KANJI);
+        QRCodeEncoder encoder = QRCodeEncoder.create(params);
+
+        Mat qrcode = new Mat();
+        encoder.encode(inp, qrcode);
+        Imgproc.resize(qrcode, qrcode, new Size(0, 0), 2, 2, Imgproc.INTER_NEAREST);
+
+        QRCodeDetector detector = new QRCodeDetector();
+        byte[] output = detector.detectAndDecodeBytes(qrcode);
+        assertEquals(detector.getEncoding(), QRCodeEncoder.ECI_SHIFT_JIS);
+        assertArrayEquals(inp, output);
+
+        List < byte[] > outputs = new ArrayList< byte[] >();
+        assertTrue(detector.detectAndDecodeBytesMulti(qrcode, outputs));
+        assertEquals(detector.getEncoding(0), QRCodeEncoder.ECI_SHIFT_JIS);
+        assertArrayEquals(inp, outputs.get(0));
+    }
 }