From ce8df3340bd23ac190ac317b2cbf4868557af9ab Mon Sep 17 00:00:00 2001
From: Milian Wolff <milian.wolff@kdab.com>
Date: Fri, 4 Sep 2015 17:13:38 +0200
Subject: [PATCH] Add hover effect.

---
 gui/flamegraph.cpp | 27 +++++++++++++++++++++------
 gui/flamegraph.h   |  5 +++++
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/gui/flamegraph.cpp b/gui/flamegraph.cpp
index d663e04..f92a12d 100644
--- a/gui/flamegraph.cpp
+++ b/gui/flamegraph.cpp
@@ -38,6 +38,7 @@
 
 FrameGraphicsItem::FrameGraphicsItem(const QRectF& rect, const quint64 cost, const QString& function, FrameGraphicsItem* parent)
     : QGraphicsRectItem(rect, parent)
+    , m_isHovered(false)
 {
     static const QString emptyLabel = QStringLiteral("???");
 
@@ -47,6 +48,7 @@ FrameGraphicsItem::FrameGraphicsItem(const QRectF& rect, const quint64 cost, con
                     function.isEmpty() ? emptyLabel : function);
     setToolTip(m_label);
     setFlag(QGraphicsItem::ItemIsSelectable);
+    setAcceptHoverEvents(true);
 }
 
 QFont FrameGraphicsItem::font()
@@ -84,10 +86,15 @@ void FrameGraphicsItem::paint(QPainter* painter, const QStyleOptionGraphicsItem*
         return;
     }
 
-    if (isSelected()) {
+    if (isSelected() || m_isHovered) {
         auto selectedColor = brush().color();
         selectedColor.setAlpha(255);
         painter->fillRect(rect(), selectedColor);
+    } else {
+        painter->fillRect(rect(), brush());
+    }
+
+    if (isSelected()) {
         const QPen oldPen = painter->pen();
         auto pen = oldPen;
         pen.setWidth(2);
@@ -95,13 +102,9 @@ void FrameGraphicsItem::paint(QPainter* painter, const QStyleOptionGraphicsItem*
         painter->drawRect(rect());
         painter->setPen(oldPen);
     } else {
-        painter->fillRect(rect(), brush());
         painter->drawRect(rect());
     }
 
-    // TODO: text should always be displayed in a constant size and not zoomed
-    // TODO: items should only be scaled horizontally, not vertically
-    // TODO: items should "fit" into the view width
     if (width < fontMetrics().averageCharWidth() * 6) {
         // text is too wide for the current LOD, don't paint it
         return;
@@ -116,6 +119,18 @@ void FrameGraphicsItem::paint(QPainter* painter, const QStyleOptionGraphicsItem*
     painter->setFont(oldFont);
 }
 
+void FrameGraphicsItem::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
+{
+    QGraphicsRectItem::hoverEnterEvent(event);
+    m_isHovered = true;
+}
+
+void FrameGraphicsItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
+{
+    QGraphicsRectItem::hoverLeaveEvent(event);
+    m_isHovered = false;
+}
+
 namespace {
 
 void scaleItems(FrameGraphicsItem *item, qreal scaleFactor)
@@ -145,7 +160,6 @@ QColor color(quint64 cost, quint64 maxCost)
     return QColor::fromHsv(120 - ratio * 120, 255, 255, (-((ratio-1) * (ratio-1))) * 120 + 120);
 }
 
-
 void toGraphicsItems(const Stack& data, qreal totalCostForColor,
                      qreal parentCost, FrameGraphicsItem *parent)
 {
@@ -223,6 +237,7 @@ FlameGraph::FlameGraph(QWidget* parent, Qt::WindowFlags flags)
     // prevent duplicate resize, when a scrollbar is shown for the first time
     m_view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
     m_view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOn);
+    m_view->viewport()->setMouseTracking(true);
 
     layout()->addWidget(m_view);
 }
diff --git a/gui/flamegraph.h b/gui/flamegraph.h
index 6722598..09b5994 100644
--- a/gui/flamegraph.h
+++ b/gui/flamegraph.h
@@ -41,8 +41,13 @@ public:
 
     void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = nullptr) override;
 
+protected:
+    void hoverEnterEvent(QGraphicsSceneHoverEvent *event) override;
+    void hoverLeaveEvent(QGraphicsSceneHoverEvent *event) override;
+
 private:
     QString m_label;
+    bool m_isHovered;
 };
 
 class FlameGraph : public QWidget
-- 
2.7.4