Fix aerodynamic_analysis gnuplot not terminating issue

Description

Previously on linux, aerodynamic_analysis terminated only with the help of pkill (killing a gnuplot instance, which was not closed). This is now solved without pkill.

• Instead of using the function to generate the plots, each plot is directly created within the routine.

Testing Instructions

1. Build on unix
2. execute and expect aerodynamic_analysis closing

Developer Checklist

• Code has been tested locally and/or in pipeline.
• (if applicable) documentation updated.
• (if applicable) impact of new dependencies reviewed and included in project.
• Merge conflicts resolved with the target branch.

aerodynamic_analysis/src/taw/tawCalculatePolarReport.cpp

@@ -166,34 +166,6 @@ auto parse_csv_file(const std::string& file_path, const std::string& column_x,
     return {x_data, y_data};
 }
 
-fs::path generate_plot(
-    const std::map<std::string, std::pair<std::vector<double>, std::vector<double>>>& data,
-    const std::string& plot_dir, const std::string& html_dir,
-    const std::string& filename, const std::string& title,
-    const std::string& xlabel, const std::string& ylabel) {
-
-    if (data.empty()) {
-        myRuntimeInfo->warn << "No data provided for plotting." << std::endl;
-    }
-
-    auto plot_path_string = helpers::prepare_plot_path(plot_dir, filename);
-
-    auto f = matplot::figure(true);
-    f->size(800, 600);
-    auto ax = f->current_axes();
-    ax->hold(true);
-
-    helpers::plot_datasets(ax, data);
-    helpers::configure_axes(ax, title, xlabel, ylabel);
-    helpers::configure_legend(ax);
-
-    matplot::save(f, plot_path_string, "svg");
-    #ifdef __unix__
-       system("pkill gnuplot");
-    #endif
-    return fs::relative(fs::path(plot_path_string), fs::path(html_dir));
-}
-
 void tawCalculatePolar::set_html_body() {
     const auto& data = myDefaultStrategy->get_default_data();
 
@@ -301,23 +273,59 @@ void tawCalculatePolar::set_html_body() {
                 lift_curve_data[label] = parse_csv_file(file_path.string(), "AoA", "C_L");
             }
 
-            auto polar_clean_plot_path = generate_plot(
-                polar_data,
-                rtIO_->getPlotDir(),
-                rtIO_->getHtmlDir(),
-                "polar_clean.svg",
-                "Polar Curve (clean configuration)",
-                "C_D",
-                "C_L");
-
-            auto lift_curve_plot_path = generate_plot(
-                lift_curve_data,
-                rtIO_->getPlotDir(),
-                rtIO_->getHtmlDir(),
-                "lift_curve_clean.svg",
-                "Lift curve (clean configuration)",
-                "AoA",
-                "C_L");
+            std::map<std::string, std::pair<std::vector<double>, std::vector<double>>> data = polar_data;
+            std::string plot_dir = rtIO_->getPlotDir();
+            std::string html_dir = rtIO_->getHtmlDir();
+            std::string filename = "polar_clean.svg"; 
+            std::string title = "Polar Curve (clean configuration)";
+            std::string xlabel = "C_D";
+            std::string ylabel = "C_L";
+
+            if (data.empty()) {
+                myRuntimeInfo->warn << "No data provided for plotting." << std::endl;
+            }
+
+            auto plot_path_string = helpers::prepare_plot_path(plot_dir, filename);
+
+            auto f = matplot::figure(true);
+            f->size(800, 600);
+            auto ax = f->current_axes();
+            ax->hold(true);
+
+            helpers::plot_datasets(ax, data);
+            helpers::configure_axes(ax, title, xlabel, ylabel);
+            helpers::configure_legend(ax);
+
+            matplot::save(f, plot_path_string, "svg");
+            auto polar_clean_plot_path = fs::relative(fs::path(plot_path_string), fs::path(html_dir));
+            ax->clear();
+            matplot::cla();
+
+            data = lift_curve_data;
+            plot_dir = rtIO_->getPlotDir();
+            html_dir = rtIO_->getHtmlDir();
+            filename = "lift_curve_clean.svg"; 
+            title = "Lift curve (clean configuration)";
+            xlabel = "AoA";
+            ylabel = "C_L";
+
+            if (data.empty()) {
+                myRuntimeInfo->warn << "No data provided for plotting." << std::endl;
+            }
+
+            plot_path_string = helpers::prepare_plot_path(plot_dir, filename);
+
+            // f = matplot::figure(true);
+            f->size(800, 600);
+            ax = f->current_axes();
+            ax->hold(true);
+
+            helpers::plot_datasets(ax, data);
+            helpers::configure_axes(ax, title, xlabel, ylabel);
+            helpers::configure_legend(ax);
+
+            matplot::save(f, plot_path_string, "svg");
+            auto lift_curve_plot_path = fs::relative(fs::path(plot_path_string), fs::path(html_dir));
 
             report_.htmlReportStream() << std::format("<img src=\"{}\" alt=\"Lift vs. Drag\"/><br>\n",
             polar_clean_plot_path.string());