android: use .getRowStride() in JavaCamera2View

modules/core/misc/java/src/java/core+Mat.java

@@ -41,6 +41,15 @@ public class Mat {
         nativeObj = n_Mat(rows, cols, type, data);
     }
 
+    //
+    // C++: Mat::Mat(int rows, int cols, int type, void* data, size_t step)
+    //
+
+    // javadoc: Mat::Mat(rows, cols, type, data, step)
+    public Mat(int rows, int cols, int type, ByteBuffer data, long step) {
+        nativeObj = n_Mat(rows, cols, type, data, step);
+    }
+
     //
     // C++: Mat::Mat(Size size, int type)
     //
@@ -1136,6 +1145,9 @@ public class Mat {
     // 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(int rows, int cols, int type, void* data, size_t step)
+    private static native long n_Mat(int rows, int cols, int type, ByteBuffer data, long step);
+
     // C++: Mat::Mat(Size size, int type)
     private static native long n_Mat(double size_width, double size_height, int type);
 

modules/core/misc/java/test/MatTest.java

@@ -1246,4 +1246,22 @@ public class MatTest extends OpenCVTestCase {
         assertEquals(1, bbuf.get(4095));
     }
 
+    public void testMatFromByteBufferWithStep() {
+        ByteBuffer bbuf = ByteBuffer.allocateDirect(80*64);
+        bbuf.putInt(0x01010101);
+        bbuf.putInt(64, 0x02020202);
+        bbuf.putInt(80, 0x03030303);
+        Mat m = new Mat(64, 64, CvType.CV_8UC1, bbuf, 80);
+        assertEquals(8, Core.countNonZero(m));
+        Core.add(m, new Scalar(5), m);
+        assertEquals(4096, Core.countNonZero(m));
+        m.release();
+        assertEquals(6, bbuf.get(0));
+        assertEquals(5, bbuf.get(63));
+        assertEquals(2, bbuf.get(64));
+        assertEquals(0, bbuf.get(79));
+        assertEquals(8, bbuf.get(80));
+        assertEquals(5, bbuf.get(63*80 + 63));
+    }
+
 }