Optimize VisualNavbar Stats Loading

src/Cutter.cpp

@@ -1537,6 +1537,11 @@ QList<SearchDescription> CutterCore::getAllSearch(QString search_for, QString sp
 
 BlockStatistics CutterCore::getBlockStatistics(unsigned int blocksCount)
 {
+    if (blocksCount == 0) {
+        BlockStatistics ret;
+        ret.from = ret.to = ret.blocksize = 0;
+        return ret;
+    }
     QJsonObject statsObj = cmdj("p-j " + QString::number(blocksCount)).object();
 
     BlockStatistics ret;

src/widgets/VisualNavbar.cpp

@@ -65,32 +65,54 @@ VisualNavbar::VisualNavbar(MainWindow *main, QWidget *parent) :
     setMouseTracking(true);
 }
 
+unsigned int nextPow2(unsigned int n)
+{
+    unsigned int b = 0;
+    while (n) {
+        n >>= 1;
+        b++;
+    }
+    return (1u << b);
+}
+
 void VisualNavbar::paintEvent(QPaintEvent *event)
 {
     Q_UNUSED(event);
 
     QPainter painter(this);
-    if (previousWidth != this->width()) {
+
+    auto w = static_cast<unsigned int>(width());
+    bool fetch = false;
+    if (statsWidth < w) {
+        statsWidth = nextPow2(w);
+        fetch = true;
+    } else if (statsWidth > w*4) {
+        statsWidth = statsWidth > 0 ? statsWidth / 2 : 0;
+        fetch = true;
+    }
+
+    if (fetch) {
         fetchAndPaintData();
-        previousWidth = this->width();
+    } else if (previousWidth != w) {
+        this->previousWidth = w;
+        updateGraphicsScene();
     }
 }
 
 void VisualNavbar::fetchAndPaintData()
 {
-    fetchData();
-    fillData();
+    fetchStats();
+    updateGraphicsScene();
 }
 
-void VisualNavbar::fetchData()
+void VisualNavbar::fetchStats()
 {
-    statsWidth = graphicsView->width();
-    stats = Core()->getBlockStatistics((unsigned int)statsWidth);
+    stats = Core()->getBlockStatistics(statsWidth);
 }
 
 enum class DataType: int { Empty, Code, String, Symbol, Count };
 
-void VisualNavbar::fillData()
+void VisualNavbar::updateGraphicsScene()
 {
     graphicsScene->clear();
     xToAddress.clear();

src/widgets/VisualNavbar.h

@@ -28,8 +28,8 @@ public slots:
 
 private slots:
     void fetchAndPaintData();
-    void fetchData();
-    void fillData();
+    void fetchStats();
+    void updateGraphicsScene();
     void drawCursor();
     void on_seekChanged(RVA addr);
 
@@ -40,13 +40,11 @@ private:
     MainWindow        *main;
 
     BlockStatistics    stats;
-    int                statsWidth;
+    unsigned int       statsWidth = 0;
+    unsigned int       previousWidth = 0;
 
     QList<XToAddress> xToAddress;
 
-    // Used to check whether the width changed. If yes we need to re-initialize the scene (slow)
-    int previousWidth = -1;
-
     RVA localXToAddress(double x);
     double addressToLocalX(RVA address);
     QList<QString> sectionsForAddress(RVA address);