feat(userInterface): add function row removal

Author: bilyayeva

include/mathplotter/userInterface.hpp

@@ -21,6 +21,7 @@ namespace mathplotter {
         std::string expression;
         sf::Color color;
         bool shouldRemove{false};
+        bool shouldErase{false};
     };
 
     class UserInterface {

src/application.cpp

@@ -144,7 +144,16 @@ namespace mathplotter {
                     )
                 };
 
-                if (submission->shouldRemove) {
+
+                if (submission->shouldErase) {
+                    if (submission->rowIndex < m_functionRenderers.size()) {
+                        m_functionRenderers.erase(
+                            m_functionRenderers.begin() +
+                            submission->rowIndex
+                        );
+                    }
+                }
+                else if (submission->shouldRemove) {
                     if (submission->rowIndex < m_functionRenderers.size()) {
                         m_functionRenderers[submission->rowIndex].reset();
                     }

src/userInterface.cpp

@@ -342,6 +342,8 @@ namespace mathplotter {
                 ImGui::GetCursorScreenPos()
             };
 
+            std::optional<std::size_t> rowToRemove;
+
             for (std::size_t i{0}; i < m_functionRows.size(); ++i) {
                 ImGui::PushID(static_cast<int>(i));
 
@@ -487,6 +489,15 @@ namespace mathplotter {
                     )
                 };
 
+                if (
+                    ImGui::IsItemActive() &&
+                    m_functionRows[i].expression.empty() &&
+                    ImGui::IsKeyPressed(ImGuiKey_Backspace) &&
+                    m_functionRows.size() > 1
+                ) {
+                    rowToRemove = i;
+                }
+
                 if (
                     ImGui::IsItemEdited() &&
                     m_functionRows[i].expression.empty()
@@ -521,6 +532,21 @@ namespace mathplotter {
 
                 ImGui::PopID();
             }
+            
+            if (rowToRemove.has_value()) {
+                submission = FunctionSubmission{
+                    *rowToRemove,
+                    "",
+                    {},
+                    false,
+                    true
+                };
+
+                m_functionRows.erase(
+                    m_functionRows.begin() + *rowToRemove
+                );
+            }
+
             ImGui::PopStyleVar();
             ImGui::PopStyleColor(3);