Support mouse gestures when active tracing is enabled (#1064)

* Make the pointer follow the mouse

* Only render when necessary

* Move trace rendering to background thread

src/GraphControl/Control/Grapher.cpp

@@ -93,11 +93,19 @@ namespace GraphControl
         {
             if (auto renderer = m_graph->GetRenderer())
             {
+                m_renderMain->GetCriticalSection().lock();
+
                 if (SUCCEEDED(renderer->ScaleRange(centerX, centerY, scale)))
                 {
+                    m_renderMain->GetCriticalSection().unlock();
+
                     m_renderMain->RunRenderPass();
                     GraphViewChangedEvent(this, ref new RoutedEventArgs());
                 }
+                else
+                {
+                    m_renderMain->GetCriticalSection().unlock();
+                }
             }
         }
     }
@@ -612,9 +620,33 @@ namespace GraphControl
     {
         if (m_renderMain)
         {
-            PointerPoint ^ currPoint = e->GetCurrentPoint(/* relativeTo */ this);
-            m_renderMain->PointerLocation = currPoint->Position;
+            Point currPosition = e->GetCurrentPoint(/* relativeTo */ this)->Position;
+
+            if (m_renderMain->ActiveTracing)
+            {
+                PointerValueChangedEvent(currPosition);
+                ActiveTraceCursorPosition = currPosition;
+
+                if (m_cachedCursor == nullptr)
+                {
+                    m_cachedCursor = ::CoreWindow::GetForCurrentThread()->PointerCursor;
+                    ::CoreWindow::GetForCurrentThread()->PointerCursor = nullptr;
+                }
+            }
+            else if (m_cachedCursor != nullptr)
+            {
+                m_renderMain->PointerLocation = currPosition;
+
+                ::CoreWindow::GetForCurrentThread()->PointerCursor = m_cachedCursor;
+                m_cachedCursor = nullptr;
+
                 UpdateTracingChanged();
+            }
+            else
+            {
+                m_renderMain->PointerLocation = currPosition;
+                UpdateTracingChanged();
+            }
 
             e->Handled = true;
         }
@@ -628,6 +660,12 @@ namespace GraphControl
             TracingChangedEvent(false);
             e->Handled = true;
         }
+
+        if (m_cachedCursor != nullptr)
+        {
+            ::CoreWindow::GetForCurrentThread()->PointerCursor = m_cachedCursor;
+            m_cachedCursor = nullptr;
+        }
     }
 
     void Grapher::OnPointerWheelChanged(PointerRoutedEventArgs ^ e)
@@ -699,11 +737,15 @@ namespace GraphControl
                     translationX /= -width;
                     translationY /= height;
 
+                    m_renderMain->GetCriticalSection().lock();
+
                     if (FAILED(renderer->MoveRangeByRatio(translationX, translationY)))
                     {
+                        m_renderMain->GetCriticalSection().unlock();
                         return;
                     }
 
+                    m_renderMain->GetCriticalSection().unlock();
                     needsRenderPass = true;
                 }
 
@@ -717,11 +759,15 @@ namespace GraphControl
                     const auto& pos = e->Position;
                     const auto [centerX, centerY] = PointerPositionToGraphPosition(pos.X, pos.Y, width, height);
 
+                    m_renderMain->GetCriticalSection().lock();
+
                     if (FAILED(renderer->ScaleRange(centerX, centerY, scale)))
                     {
+                        m_renderMain->GetCriticalSection().unlock();
                         return;
                     }
 
+                    m_renderMain->GetCriticalSection().unlock();
                     needsRenderPass = true;
                 }
 

src/GraphControl/Control/Grapher.h

@@ -333,6 +333,7 @@ public
         bool m_KeysPressed[5];
         bool m_Moving;
         Windows::UI::Xaml::DispatcherTimer ^ m_TracingTrackingTimer;
+        Windows::UI::Core::CoreCursor ^ m_cachedCursor;
 
     public:
         Windows::Storage::Streams::RandomAccessStreamReference ^ GetGraphBitmapStream();

src/GraphControl/DirectX/RenderMain.cpp

@@ -86,7 +86,12 @@ namespace GraphControl::DX
             {
                 m_Tracing = false;
             }
-            RunRenderPass();
+
+            bool wasPointRendered = m_Tracing;
+            if (CanRenderPoint() || wasPointRendered)
+            {
+                RunRenderPassAsync();
+            }
         }
     }
 
@@ -95,7 +100,12 @@ namespace GraphControl::DX
         if (m_pointerLocation != location)
         {
             m_pointerLocation = location;
-            RunRenderPass();
+
+            bool wasPointRendered = m_Tracing;
+            if (CanRenderPoint() || wasPointRendered)
+            {
+                RunRenderPassAsync();
+            }
         }
     }
 
@@ -104,7 +114,12 @@ namespace GraphControl::DX
         if (m_drawActiveTracing != value)
         {
             m_drawActiveTracing = value;
-            RunRenderPass();
+
+            bool wasPointRendered = m_Tracing;
+            if (CanRenderPoint() || wasPointRendered)
+            {
+                RunRenderPassAsync();
+            }
         }
     }
 
@@ -127,6 +142,51 @@ namespace GraphControl::DX
         }
     }
 
+    bool RenderMain::CanRenderPoint()
+    {
+        if (m_drawNearestPoint || m_drawActiveTracing)
+        {
+            Point trackPoint = m_pointerLocation;
+
+            if (m_drawActiveTracing)
+            {
+                trackPoint = m_activeTracingPointerLocation;
+            }
+
+            if (!m_criticalSection.try_lock())
+            {
+                return false;
+            }
+
+            m_criticalSection.unlock();
+
+            critical_section::scoped_lock lock(m_criticalSection);
+
+            int formulaId = -1;
+            float nearestPointLocationX, nearestPointLocationY;
+            double nearestPointValueX, nearestPointValueY, rhoValueOut, thetaValueOut, tValueOut;
+            m_Tracing = m_graph->GetRenderer()->GetClosePointData(
+                            trackPoint.X,
+                            trackPoint.Y,
+                            formulaId,
+                            nearestPointLocationX,
+                            nearestPointLocationY,
+                            nearestPointValueX,
+                            nearestPointValueY,
+                            rhoValueOut,
+                            thetaValueOut,
+                            tValueOut)
+                        == S_OK;
+            m_Tracing = m_Tracing && !isnan(nearestPointLocationX) && !isnan(nearestPointLocationY);
+        }
+        else
+        {
+            m_Tracing = false;
+        }
+
+        return m_Tracing;
+    }
+
     bool RenderMain::RunRenderPass()
     {
         // Non async render passes cancel if they can't obtain the lock immediatly

src/GraphControl/DirectX/RenderMain.h

@@ -45,6 +45,8 @@ namespace GraphControl::DX
 
         void CreateWindowSizeDependentResources();
 
+        bool RenderMain::CanRenderPoint();
+
         bool RunRenderPass();
 
         Windows::Foundation::IAsyncAction ^ RunRenderPassAsync(bool allowCancel = true);
@@ -78,7 +80,12 @@ namespace GraphControl::DX
                 if (m_activeTracingPointerLocation != newValue)
                 {
                     m_activeTracingPointerLocation = newValue;
-                    RunRenderPass();
+
+                    bool wasPointRendered = m_Tracing;
+                    if (CanRenderPoint() || wasPointRendered)
+                    {
+                        RunRenderPassAsync();
+                    }
                 }
             }
         }