From 10edc6b0ac40c3b54c75ce4b6d3497980431c9d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20=C4=8Cert=C3=ADk?= <ondrej@certik.us>
Date: Tue, 26 Nov 2019 13:40:05 -0700
Subject: [PATCH] Skip drawing the line for negative values

---
 lib/jkqtplotter/graphs/jkqtpscatter.cpp | 34 +++++++++++++++----------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/lib/jkqtplotter/graphs/jkqtpscatter.cpp b/lib/jkqtplotter/graphs/jkqtpscatter.cpp
index 9dc19035a2..dd265cb108 100644
--- a/lib/jkqtplotter/graphs/jkqtpscatter.cpp
+++ b/lib/jkqtplotter/graphs/jkqtpscatter.cpp
@@ -34,7 +34,11 @@
 
 
 
-
+template<typename T, typename... Args>
+std::unique_ptr<T> make_unique(Args&&... args)
+{
+    return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
 
 
 
@@ -94,7 +98,8 @@ void JKQTPXYLineGraph::draw(JKQTPEnhancedPainter& painter) {
         //double yold=-1;
         //bool first=false;
         //QVector<QLineF> lines;
-        QPolygonF linesP;
+        std::vector<std::unique_ptr<QPolygonF>> linesP;
+        linesP.push_back(make_unique<QPolygonF>());
         intSortData();
         for (int iii=imin; iii<imax; iii++) {
             int i=qBound(imin, getDataIndex(iii), imax);
@@ -110,24 +115,27 @@ void JKQTPXYLineGraph::draw(JKQTPEnhancedPainter& painter) {
                 }
                 if ((!parent->getXAxis()->isLogAxis() || xv>0.0) && (!parent->getYAxis()->isLogAxis() || yv>0.0) ) {
                     plotStyledSymbol(parent, painter, x, y);
-                }
-                if (drawLine) {
-                    linesP<<QPointF(x,y);
-
+                    if (drawLine) {
+                        (*linesP[linesP.size()-1])<<QPointF(x,y);
+                    }
+                } else {
+                    linesP.push_back(make_unique<QPolygonF>());
                 }
             }
         }
         //qDebug()<<"JKQTPXYLineGraph::draw(): "<<4<<" lines="<<lines.size();
         //qDebug()<<"JKQTPXYLineGraph::draw(): "<<5<<"  p="<<painter.pen();
-        if (linesP.size()>0) {
-            if (isHighlighted()) {
-                painter.setPen(penSelection);
+        for (auto &lines : linesP) {
+            if (lines->size()>0) {
+                if (isHighlighted()) {
+                    painter.setPen(penSelection);
+                    //painter.drawLines(lines);
+                    painter.drawPolyline(*lines);
+                }
+                painter.setPen(p);
                 //painter.drawLines(lines);
-                painter.drawPolyline(linesP);
+                painter.drawPolyline(*lines);
             }
-            painter.setPen(p);
-            //painter.drawLines(lines);
-            painter.drawPolyline(linesP);
         }
         //qDebug()<<"JKQTPXYLineGraph::draw(): "<<6;
     }