From 2e772510ea1a26c4b248e7ea06206e04e5369211 Mon Sep 17 00:00:00 2001
From: Florian Echtler <floe@butterbrot.org>
Date: Fri, 10 Nov 2017 20:35:32 +0100
Subject: [PATCH] Merge pull request #10050 from floe/android-studio-3.3.1

Add Android Mat constructor with support for native buffer (#10050)
---
 modules/core/misc/java/src/java/core+Mat.java | 18 ++++++++++++++++++
 modules/core/misc/java/test/MatTest.java      | 13 +++++++++++++
 modules/java/generator/src/cpp/Mat.cpp        | 25 +++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/modules/core/misc/java/src/java/core+Mat.java b/modules/core/misc/java/src/java/core+Mat.java
index 6db2554..98cdba9 100644
--- a/modules/core/misc/java/src/java/core+Mat.java
+++ b/modules/core/misc/java/src/java/core+Mat.java
@@ -1,5 +1,7 @@
 package org.opencv.core;
 
+import java.nio.ByteBuffer;
+
 // C++: class Mat
 //javadoc: Mat
 public class Mat {
@@ -40,6 +42,19 @@ public class Mat {
     }
 
     //
+    // C++: Mat::Mat(int rows, int cols, int type, void* data)
+    //
+
+    // javadoc: Mat::Mat(rows, cols, type, data)
+    public Mat(int rows, int cols, int type, ByteBuffer data)
+    {
+
+        nativeObj = n_Mat(rows, cols, type, data);
+
+        return;
+    }
+
+    //
     // C++: Mat::Mat(Size size, int type)
     //
 
@@ -1101,6 +1116,9 @@ public class Mat {
     // C++: Mat::Mat(int rows, int cols, int type)
     private static native long n_Mat(int rows, int cols, int type);
 
+    // C++: Mat::Mat(int rows, int cols, int type, void* data)
+    private static native long n_Mat(int rows, int cols, int type, ByteBuffer data);
+
     // C++: Mat::Mat(Size size, int type)
     private static native long n_Mat(double size_width, double size_height, int type);
 
diff --git a/modules/core/misc/java/test/MatTest.java b/modules/core/misc/java/test/MatTest.java
index 3ff0c8b..7d0731a 100644
--- a/modules/core/misc/java/test/MatTest.java
+++ b/modules/core/misc/java/test/MatTest.java
@@ -1,6 +1,7 @@
 package org.opencv.test.core;
 
 import java.util.Arrays;
+import java.nio.ByteBuffer;
 
 import org.opencv.core.Core;
 import org.opencv.core.CvException;
@@ -1001,4 +1002,16 @@ public class MatTest extends OpenCVTestCase {
         assertMatEqual(truth, dst);
     }
 
+    public void testMatFromByteBuffer() {
+        ByteBuffer bbuf = ByteBuffer.allocateDirect(64*64);
+        bbuf.putInt(0x01010101);
+        Mat m = new Mat(64,64,CvType.CV_8UC1,bbuf);
+        assertEquals(4, Core.countNonZero(m));
+        Core.add(m, new Scalar(1), m);
+        assertEquals(4096, Core.countNonZero(m));
+        m.release();
+        assertEquals(2, bbuf.get(0));
+        assertEquals(1, bbuf.get(4095));
+    }
+
 }
diff --git a/modules/java/generator/src/cpp/Mat.cpp b/modules/java/generator/src/cpp/Mat.cpp
index c85a3d7..6122a7e 100644
--- a/modules/java/generator/src/cpp/Mat.cpp
+++ b/modules/java/generator/src/cpp/Mat.cpp
@@ -52,6 +52,31 @@ JNIEXPORT jlong JNICALL Java_org_opencv_core_Mat_n_1Mat__
 
 
 //
+//   Mat::Mat(int rows, int cols, int type, void* data)
+//
+
+JNIEXPORT jlong JNICALL Java_org_opencv_core_Mat_n_1Mat__IIILjava_nio_ByteBuffer_2
+  (JNIEnv* env, jclass, jint rows, jint cols, jint type, jobject data);
+
+JNIEXPORT jlong JNICALL Java_org_opencv_core_Mat_n_1Mat__IIILjava_nio_ByteBuffer_2
+  (JNIEnv* env, jclass, jint rows, jint cols, jint type, jobject data)
+{
+    static const char method_name[] = "Mat::n_1Mat__IIILByteBuffer()";
+    try {
+        LOGD("%s", method_name);
+        return (jlong) new Mat( rows, cols, type, (void*)env->GetDirectBufferAddress(data) );
+    } catch(const std::exception &e) {
+        throwJavaException(env, &e, method_name);
+    } catch (...) {
+        throwJavaException(env, 0, method_name);
+    }
+
+    return 0;
+}
+
+
+
+//
 //   Mat::Mat(int rows, int cols, int type)
 //
 
-- 
2.7.4