Add variable editing (#581)

src/GraphControl/Control/Grapher.cpp

@@ -26,8 +26,12 @@ namespace
     constexpr auto s_propertyName_EquationTemplate = L"EquationTemplate";
     constexpr auto s_propertyName_Equations = L"Equations";
     constexpr auto s_propertyName_EquationsSource = L"EquationsSource";
+    constexpr auto s_propertyName_Variables = L"Variables";
     constexpr auto s_propertyName_ForceProportionalAxes = L"ForceProportionalAxes";
 
+    constexpr auto s_X = L"x";
+    constexpr auto s_Y = L"y";
+
     // Helper function for converting a pointer position to a position that the graphing engine will understand.
     // posX/posY are the pointer position elements and width,height are the dimensions of the graph surface.
     // The graphing engine interprets x,y position between the range [-1, 1].
@@ -43,6 +47,7 @@ namespace GraphControl
     DependencyProperty^ Grapher::s_equationTemplateProperty;
     DependencyProperty^ Grapher::s_equationsProperty;
     DependencyProperty^ Grapher::s_equationsSourceProperty;
+    DependencyProperty^ Grapher::s_variablesProperty;
     DependencyProperty^ Grapher::s_forceProportionalAxesTemplateProperty;
     
     Grapher::Grapher()
@@ -54,6 +59,7 @@ namespace GraphControl
         DefaultStyleKey = StringReference(s_defaultStyleKey);
 
         this->SetValue(EquationsProperty, ref new EquationCollection());
+        this->SetValue(VariablesProperty, ref new Map<String^, double>());
 
         this->Loaded += ref new RoutedEventHandler(this, &Grapher::OnLoaded);
         this->Unloaded += ref new RoutedEventHandler(this, &Grapher::OnUnloaded);
@@ -145,6 +151,17 @@ namespace GraphControl
                     ref new PropertyChangedCallback(&Grapher::OnCustomDependencyPropertyChanged)));
         }
 
+        if (!s_variablesProperty)
+        {
+            s_variablesProperty = DependencyProperty::Register(
+                StringReference(s_propertyName_Variables),
+                IObservableMap<String^, double>::typeid,
+                Grapher::typeid,
+                ref new PropertyMetadata(
+                    nullptr,
+                    ref new PropertyChangedCallback(&Grapher::OnCustomDependencyPropertyChanged)));
+        }
+
         if (!s_forceProportionalAxesTemplateProperty)
         {
             s_forceProportionalAxesTemplateProperty = DependencyProperty::Register(
@@ -350,8 +367,11 @@ namespace GraphControl
                     if (m_graph->TryInitialize(graphExpression.get()))
                     {
                         UpdateGraphOptions(m_graph->GetOptions(), validEqs);
+                        SetGraphArgs();
 
                         m_renderMain->Graph = m_graph;
+
+                        UpdateVariables();
                     }
                 }
             }
@@ -360,13 +380,80 @@ namespace GraphControl
                 if (m_graph->TryInitialize())
                 {
                     UpdateGraphOptions(m_graph->GetOptions(), validEqs);
+                    SetGraphArgs();
 
                     m_renderMain->Graph = m_graph;
+
+                    UpdateVariables();
                 }
             }
         }
     }
 
+    void Grapher::SetGraphArgs()
+    {
+        if (m_graph)
+        {
+            for (auto variable : Variables)
+            {
+                m_graph->SetArgValue(variable->Key->Data(), variable->Value);
+            }
+        }
+    }
+
+    void Grapher::UpdateVariables()
+    {
+        auto updatedVariables = ref new Map<String^, double>();
+        if (m_graph)
+        {
+            auto graphVariables = m_graph->GetVariables();
+
+            for (auto graphVar : graphVariables)
+            {
+                if (graphVar->GetVariableName() != s_X && graphVar->GetVariableName() != s_Y)
+                {
+                    auto key = ref new String(graphVar->GetVariableName().data());
+                    double value = 1.0;
+
+                    if (Variables->HasKey(key))
+                    {
+                        value = Variables->Lookup(key);
+                    }
+
+                    updatedVariables->Insert(key, value);
+                }
+            }
+        }
+
+        Variables = updatedVariables;
+        VariablesUpdated(this, Variables);
+    }
+
+    void Grapher::SetVariable(Platform::String^ variableName, double newValue)
+    {
+        if (Variables->HasKey(variableName))
+        {
+            if (Variables->Lookup(variableName) == newValue)
+            {
+                return;
+            }
+
+            Variables->Remove(variableName);
+        }
+
+        Variables->Insert(variableName, newValue);
+
+        if (m_graph)
+        {
+            m_graph->SetArgValue(variableName->Data(), newValue);
+
+            if (m_renderMain)
+            {
+                m_renderMain->RunRenderPass();
+            }
+        }
+    }
+
     void Grapher::UpdateGraphOptions(IGraphingOptions& options, const vector<Equation^>& validEqs)
     {
         options.SetForceProportional(ForceProportionalAxes);

src/GraphControl/Control/Grapher.h

@@ -5,6 +5,7 @@
 #include "Equation.h"
 #include "EquationCollection.h"
 #include "IMathSolver.h"
+#include "Common.h"
 
 namespace GraphControl
 {
@@ -78,6 +79,29 @@ namespace GraphControl
         }
         #pragma endregion
 
+        #pragma region Windows::Foundation::Collections::IObservableMap<Platform::String^, double>^ Variables DependencyProperty
+        static property Windows::UI::Xaml::DependencyProperty^ VariablesProperty
+        {
+            Windows::UI::Xaml::DependencyProperty^ get()
+            {
+                return s_variablesProperty;
+            }
+        }
+
+        property Windows::Foundation::Collections::IObservableMap<Platform::String^, double>^ Variables
+        {
+            Windows::Foundation::Collections::IObservableMap<Platform::String^, double>^ get()
+            {
+                return static_cast<Windows::Foundation::Collections::IObservableMap<Platform::String^, double>^>(GetValue(s_variablesProperty));
+            }
+
+            void set(Windows::Foundation::Collections::IObservableMap<Platform::String^, double>^ value)
+            {
+                SetValue(s_variablesProperty, value);
+            }
+        }
+        #pragma endregion
+
         #pragma region Windows::UI::Xaml::DataTemplate^ ForceProportionalAxes DependencyProperty
         static property Windows::UI::Xaml::DependencyProperty^ ForceProportionalAxesTemplateProperty
         {
@@ -100,6 +124,10 @@ namespace GraphControl
         }
         #pragma endregion
 
+        event Windows::Foundation::EventHandler<Windows::Foundation::Collections::IMap<Platform::String^, double>^>^ VariablesUpdated;
+
+        void SetVariable(Platform::String^ variableName, double newValue);
+
     protected:
         #pragma region Control Overrides
         void OnApplyTemplate() override;
@@ -127,12 +155,14 @@ namespace GraphControl
         void OnDataSourceChanged(GraphControl::InspectingDataSource^ sender, GraphControl::DataSourceChangedEventArgs args);
 
         void OnEquationsChanged(Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ args);
-        void OnEquationsVectorChanged(Windows::Foundation::Collections::IObservableVector<GraphControl::Equation ^> ^sender, Windows::Foundation::Collections::IVectorChangedEventArgs ^event);
+        void OnEquationsVectorChanged(Windows::Foundation::Collections::IObservableVector<GraphControl::Equation ^> ^sender, Windows::Foundation::Collections::IVectorChangedEventArgs^ event);
         void OnEquationChanged();
 
         void UpdateGraph();
         void UpdateGraphOptions(Graphing::IGraphingOptions& options, const std::vector<Equation^>& validEqs);
         std::vector<Equation^> GetValidEquations();
+        void SetGraphArgs();
+        void UpdateVariables();
 
         void OnForceProportionalAxesChanged(Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ args);
 
@@ -154,6 +184,7 @@ namespace GraphControl
         Windows::Foundation::EventRegistrationToken m_tokenDataSourceChanged;
 
         static Windows::UI::Xaml::DependencyProperty^ s_equationsProperty;
+        static Windows::UI::Xaml::DependencyProperty^ s_variablesProperty;
         Windows::Foundation::EventRegistrationToken m_tokenEquationsChanged;
         Windows::Foundation::EventRegistrationToken m_tokenEquationChanged;