Update plot module (#1367)

* Update plot.hpp

* update

* plot_demo

* remove_tabs

* Update plot_demo.cpp

* Update plot.hpp

* Update plot.hpp

modules/plot/samples/plot_demo.cpp

@@ -0,0 +1,35 @@
+#include <opencv2/highgui.hpp>
+#include <opencv2/plot.hpp>
+#include <iostream>
+
+using namespace cv;
+
+int main()
+{
+    Mat data_x(1, 50, CV_64F);
+    Mat data_y(1, 50, CV_64F);
+
+    for (int i = 0; i < 50; i++)
+    {
+        data_x.at<double>(0, i) = (i - 25);
+        data_y.at<double>(0, i) = (i - 25)*(i - 25)*(i - 25);
+    }
+
+    std::cout << "data_x : " << data_x << std::endl;
+    std::cout << "data_y : " << data_y << std::endl;
+
+    Mat plot_result;
+
+    Ptr<plot::Plot2d> plot = plot::Plot2d::create(data_x, data_y);
+    plot->render(plot_result);
+
+    imshow("default orientation", plot_result);
+
+    plot = plot::Plot2d::create(data_x, data_y,true);
+    plot->render(plot_result);
+
+    imshow("inverted orientation", plot_result);
+    waitKey();
+
+    return 0;
+}