Fix drawKeypoints and drawMatches for JS

modules/js/test/test_features2d.js

@@ -80,3 +80,36 @@ QUnit.test('BFMatcher', function(assert) {
 
   assert.equal(dm.size(), 67);
 });
+
+QUnit.test('Drawing', function(assert) {
+  // Generate key points.
+  let image = generateTestFrame();
+
+  let kp = new cv.KeyPointVector();
+  let descriptors = new cv.Mat();
+  let orb = new cv.ORB();
+  orb.detectAndCompute(image, new cv.Mat(), kp, descriptors);
+  assert.equal(kp.size(), 67);
+
+  let dst = new cv.Mat();
+  cv.drawKeypoints(image, kp, dst);
+  assert.equal(dst.rows, image.rows);
+  assert.equal(dst.cols, image.cols);
+
+  // Run a matcher.
+  let dm = new cv.DMatchVector();
+  let matcher = new cv.BFMatcher();
+  matcher.match(descriptors, descriptors, dm);
+  assert.equal(dm.size(), 67);
+
+  cv.drawMatches(image, kp, image, kp, dm, dst);
+  assert.equal(dst.rows, image.rows);
+  assert.equal(dst.cols, 2 * image.cols);
+
+  dm = new cv.DMatchVectorVector();
+  matcher.knnMatch(descriptors, descriptors, dm, 2);
+  assert.equal(dm.size(), 67);
+  cv.drawMatchesKnn(image, kp, image, kp, dm, dst);
+  assert.equal(dst.rows, image.rows);
+  assert.equal(dst.cols, 2 * image.cols);
+});