[curve] Optimize drawing when we have many many points

src/plugins/score-plugin-curve/Curve/CurvePresenter.cpp

@@ -109,13 +109,24 @@ void Presenter::setPos(SegmentView& segment)
   segment.setRect({0., 0., endx - startx, m_localRect.height()});
 }
 
+static constexpr int direct_draw_cutoff = 3000;
 void Presenter::setupSignals()
 {
   con(m_model, &Model::segmentAdded, this, [&](const SegmentModel* segment) {
+    if(m_model.points().size() > direct_draw_cutoff)
+    {
+      m_view->setDirectDraw(true);
+      return;
+    }
     addSegment(new SegmentView{segment, m_style, m_view});
   });
 
   con(m_model, &Model::pointAdded, this, [&](const PointModel* point) {
+    if(m_model.points().size() > direct_draw_cutoff)
+    {
+      m_view->setDirectDraw(true);
+      return;
+    }
     addPoint(new PointView{point, m_style, m_view});
   });
 
@@ -126,6 +137,7 @@ void Presenter::setupSignals()
       [&](const Id<SegmentModel>& m) { m_segments.erase(m); });
 
   con(m_model, &Model::cleared, this, [&]() {
+    m_view->setDirectDraw(false);
     m_points.remove_all();
     m_segments.remove_all();
   });
@@ -136,14 +148,23 @@ void Presenter::setupSignals()
 void Presenter::setupView()
 {
   // Initialize the elements
-  for(const auto& segment : m_model.segments())
+  m_view->setModel(this, &m_model);
+  if(m_model.points().size() < 3000)
   {
-    addSegment(new SegmentView{&segment, m_style, m_view});
-  }
+    for(const auto& segment : m_model.segments())
+    {
+      addSegment(new SegmentView{&segment, m_style, m_view});
+    }
 
-  for(PointModel* pt : m_model.points())
+    for(PointModel* pt : m_model.points())
+    {
+      addPoint(new PointView{pt, m_style, m_view});
+    }
+    m_view->setDirectDraw(false);
+  }
+  else
   {
-    addPoint(new PointView{pt, m_style, m_view});
+    m_view->setDirectDraw(true);
   }
 }
 
@@ -258,6 +279,19 @@ void Presenter::setupSegmentConnections(SegmentView* seg_view)
 
 void Presenter::modelReset()
 {
+  const int64_t model_points_n = m_model.points().size();
+  if(model_points_n > direct_draw_cutoff)
+  {
+    m_points.remove_all();
+    m_segments.remove_all();
+    m_view->setDirectDraw(true);
+    return;
+  }
+  else
+  {
+    m_view->setDirectDraw(false);
+  }
+
   // 1. We put our current elements in our pool.
   std::vector<PointView*> points = m_points.as_vec();
   std::vector<SegmentView*> segments = m_segments.as_vec();

src/plugins/score-plugin-curve/Curve/CurvePresenter.hpp

@@ -30,6 +30,7 @@ class Model;
 
 class SCORE_PLUGIN_CURVE_EXPORT Presenter final : public QObject
 {
+  friend class View;
   W_OBJECT(Presenter)
 public:
   Presenter(

src/plugins/score-plugin-curve/Curve/CurveStyle.cpp

@@ -27,5 +27,8 @@ void Style::update()
   PenPointSelected = PointSelected.color();
   BrushPoint = Point;
   BrushPointSelected = PointSelected;
+
+  PenDataset = QPen{Segment, 1, Qt::PenStyle::SolidLine};
+  PenDatasetDisabled = QPen{SegmentDisabled, 1, Qt::PenStyle::SolidLine};
 }
 }

src/plugins/score-plugin-curve/Curve/CurveStyle.hpp

@@ -29,6 +29,9 @@ struct SCORE_PLUGIN_CURVE_EXPORT Style
   QBrush BrushPoint{};
   QBrush BrushPointSelected{};
 
+  QPen PenDataset{};
+  QPen PenDatasetDisabled{};
+
   void init(const score::Skin& s);
   void update();
 };

src/plugins/score-plugin-curve/Curve/CurveView.cpp

@@ -4,6 +4,11 @@
 
 #include <Process/Style/ScenarioStyle.hpp>
 
+#include <Curve/CurveModel.hpp>
+#include <Curve/CurvePresenter.hpp>
+#include <Curve/CurveStyle.hpp>
+#include <Curve/Point/CurvePointModel.hpp>
+
 #include <QGraphicsSceneMouseEvent>
 #include <QKeyEvent>
 #include <QPainter>
@@ -33,6 +38,17 @@ View::View(QGraphicsItem* parent) noexcept
 
 View::~View() { }
 
+void View::setModel(const Presenter* p, const Model* m) noexcept
+{
+  m_presenter = p;
+  m_model = m;
+}
+
+void View::setDirectDraw(bool d) noexcept
+{
+  m_directDraw = d;
+}
+
 void View::paint(
     QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget)
 {
@@ -41,6 +57,29 @@ void View::paint(
     painter->setPen(Qt::white);
     painter->drawRect(m_selectArea);
   }
+
+  if(m_directDraw)
+  {
+    auto& pts = m_model->points();
+    if(pts.size() < 2)
+      return;
+
+    auto& style = m_presenter->m_style;
+    painter->setPen(
+        m_presenter->m_enabled ? style.PenDataset : style.PenDatasetDisabled);
+    static constexpr auto scale = [](QPointF first, QSizeF second) {
+      return QPointF{first.x() * second.width(), (1. - first.y()) * second.height()};
+    };
+
+    auto sz = m_presenter->m_localRect.size();
+    for(auto orig = pts.begin(), next = ++pts.begin(); next != pts.end(); ++orig, ++next)
+    {
+      auto p1 = scale((*orig)->pos(), sz);
+      auto p2 = scale((*next)->pos(), sz);
+
+      painter->drawLine(p1.x(), p1.y(), p2.x(), p2.y());
+    }
+  }
 }
 
 void View::setSelectionArea(const QRectF& rect) noexcept

src/plugins/score-plugin-curve/Curve/CurveView.hpp

@@ -17,6 +17,8 @@ class QWidget;
 
 namespace Curve
 {
+class Presenter;
+class Model;
 class SCORE_PLUGIN_CURVE_EXPORT View final
     : public QObject
     , public QGraphicsItem
@@ -27,6 +29,8 @@ class SCORE_PLUGIN_CURVE_EXPORT View final
   explicit View(QGraphicsItem* parent) noexcept;
   ~View() override;
 
+  void setModel(const Curve::Presenter* p, const Curve::Model* m) noexcept;
+  void setDirectDraw(bool) noexcept;
   void setDefaultWidth(double w) noexcept;
   void setRect(const QRectF& theRect) noexcept;
   QRectF boundingRect() const override;
@@ -64,10 +68,13 @@ class SCORE_PLUGIN_CURVE_EXPORT View final
 
   void contextMenuEvent(QGraphicsSceneContextMenuEvent*) override;
 
+  const Curve::Presenter* m_presenter{};
+  const Curve::Model* m_model{};
   QRectF m_rect; // The rect in which the whole curve must fit.
   QRectF m_selectArea;
   QPointF m_tooltipPos;
   QString m_tooltip;
   double m_defaultW{};
+  bool m_directDraw{false};
 };
 }