Java bindings for QR code with bytes encoding/decoding

modules/objdetect/include/opencv2/objdetect.hpp

@@ -810,12 +810,12 @@ public:
     CV_WRAP std::string detectAndDecodeCurved(InputArray img, OutputArray points=noArray(),
                                               OutputArray straight_qrcode = noArray());
 
-    /** @brief Returns a kid of encoding for the decoded info from the latest QR codes
+    /** @brief Returns a kind of encoding for the decoded info from the latest @ref decode or @ref detectAndDecode call
     @param codeIdx an index of the previously decoded QR code.
                    When @ref decode or @ref detectAndDecode is used, valid value is zero.
                    For @ref decodeMulti or @ref detectAndDecodeMulti use indices corresponding to the output order.
     */
-    CV_WRAP QRCodeEncoder::ECIEncodings getEncoding(size_t codeIdx = 0);
+    CV_WRAP QRCodeEncoder::ECIEncodings getEncoding(int codeIdx = 0);
 };
 
 class CV_EXPORTS_W_SIMPLE QRCodeDetectorAruco : public GraphicalCodeDetector {

modules/objdetect/misc/java/gen_dict.json

@@ -0,0 +1,92 @@
+{
+    "ManualFuncs" : {
+        "QRCodeEncoder" : {
+            "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",
+                    "*/",
+                    "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"
+                ]
+            }
+        },
+        "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"
+                ]
+            }
+        }
+    }
+}

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

@@ -2,13 +2,18 @@ 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;
 
 public class QRCodeDetectorTest extends OpenCVTestCase {
 
@@ -50,4 +55,21 @@ 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() throws UnsupportedEncodingException {
+        String inp = new String("こんにちは世界");
+
+        QRCodeEncoder_Params params = new QRCodeEncoder_Params();
+        params.set_mode(QRCodeEncoder.MODE_KANJI);
+        QRCodeEncoder encoder = QRCodeEncoder.create(params);
+
+        Mat qrcode = new Mat();
+        encoder.encode(inp.getBytes("Shift_JIS"), 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);
+        assertEquals(inp, new String(output, "Shift_JIS"));
+    }
 }

modules/objdetect/src/qrcode.cpp

@@ -980,7 +980,7 @@ public:
 
     std::string detectAndDecodeCurved(InputArray in, OutputArray points, OutputArray straight_qrcode);
 
-    QRCodeEncoder::ECIEncodings getEncoding(size_t codeIdx);
+    QRCodeEncoder::ECIEncodings getEncoding(int codeIdx);
 };
 
 QRCodeDetector::QRCodeDetector() {
@@ -997,8 +997,9 @@ QRCodeDetector& QRCodeDetector::setEpsY(double epsY) {
     return *this;
 }
 
-QRCodeEncoder::ECIEncodings QRCodeDetector::getEncoding(size_t codeIdx) {
+QRCodeEncoder::ECIEncodings QRCodeDetector::getEncoding(int codeIdx) {
     auto& encodings = std::dynamic_pointer_cast<ImplContour>(p)->encodings;
+    CV_Assert(codeIdx >= 0);
     CV_Assert(codeIdx < encodings.size());
     return encodings[codeIdx];
 }