From 9faf0f5a772a97da155d1f8979af09d38d1f427f Mon Sep 17 00:00:00 2001
From: Adrian Sieber <mail@adriansieber.com>
Date: Thu, 8 Oct 2015 22:00:12 +0200
Subject: [PATCH] Add function argument to specify the threshold algorithm

---
 src/Matrix.cc | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/Matrix.cc b/src/Matrix.cc
index 06928c4..b2bd640 100755
--- a/src/Matrix.cc
+++ b/src/Matrix.cc
@@ -1635,7 +1635,7 @@ NAN_METHOD(Matrix::Threshold) {
   double maxVal = info[1]->NumberValue();
   int typ = cv::THRESH_BINARY;
 
-  if (info.Length() == 3) {
+  if (info.Length() >= 3) {
     Nan::Utf8String typstr(info[2]);
 
     if (strcmp(*typstr, "Binary") == 0) {
@@ -1669,6 +1669,29 @@ NAN_METHOD(Matrix::Threshold) {
     }
   }
 
+  if (info.Length() >= 4) {
+    Nan::Utf8String algorithm(info[3]);
+
+    if (strcmp(*algorithm, "Simple") == 0) {
+        // Uses default
+    }
+    else if (strcmp(*algorithm, "Otsu") == 0) {
+      typ += 8;
+    }
+    else {
+      char *algo = *algorithm;
+      char text[] = "\" is no supported threshold algorithm. "
+        "Use \"Simple\" (default) or \"Otsu\".";
+      char errorMessage[strlen(algo) + strlen(text) + 2];
+      strcpy(errorMessage, "\"");
+      strcat(errorMessage, algo);
+      strcat(errorMessage, text);
+
+      Nan::ThrowError(errorMessage);
+      return;
+    }
+  }
+
   Local < Object > img_to_return =
       Nan::New(Matrix::constructor)->GetFunction()->NewInstance();
   Matrix *img = Nan::ObjectWrap::Unwrap<Matrix>(img_to_return);