Voronoi diagram on chart

.. The diagram now displays on a chart, but there are a few issues.
   Will work through them as more testing done.

contrib/voronoi/Voronoi.cpp

@@ -8,9 +8,21 @@
 Voronoi::Voronoi()
 {
     // old controls essentially in main.c
-    triangulate = 0;
-    plot = 0;
-    debug = 0;
+    //
+    // the original source was written in such a way that you could
+    // update the "plotting functions" (line, circle etc) with your
+    // own code to implement a plot.
+    //
+    // we have adapted the "line" function to record lines in the
+    // output vector, so we can draw them on a plot
+    //
+    // testing has suggested that these kinds of diagrams only work
+    // well when there are lots of cells ie, running kmeans with
+    // 30 or even 100 clusters.
+    //
+    triangulate = 0; // tesselate (we don't support this)
+    plot = 1; // call "plotting functions" - we use this
+    debug = 0; // set to 1 to get lots of debug
 
     // malloc lists are maintained and zapped in constructors
     freeinit(&sfl, sizeof(Site));
@@ -98,6 +110,7 @@ Voronoi::run(QRectF /* boundingRect */)
 
     // was done in main.c previously
     geominit();
+    plotinit();
 
     // now into the original sources
     Site *newsite, * bot, * top, * temp, * p, * v ;
@@ -755,11 +768,13 @@ Voronoi::myalloc(unsigned n)
 void
 Voronoi::openpl(void)
     {
+        output.clear();
     }
 
 void
 Voronoi::line(float ax, float ay, float bx, float by)
     {
+        output << QLineF(QPointF(ax,ay), QPointF(bx,by));
     }
 
 void

contrib/voronoi/Voronoi.h

@@ -3,6 +3,7 @@
 #include <QList>
 #include <QRectF>
 #include <QPointF>
+#include <QLineF>
 
 #ifndef __VDEFS_H
 #define __VDEFS_H 1
@@ -76,6 +77,9 @@ class Voronoi {
         void addSite(QPointF point);
         void run(QRectF boundingRect);
 
+        // the output is a vector of lines to draw
+        QList<QLineF> &lines() { return output; }
+
     private:
 
         // original global variables
@@ -99,6 +103,7 @@ class Voronoi {
         // refactoring to Qt containers
         QList<void *> malloclist; // keep tabs on all the malloc'ed memory
         QList<Site*> sites;
+        QList<QLineF> output;
 
         /*** implicit parameters: nsites, sqrt_nsites, xmin, xmax, ymin, ymax,
          : deltax, deltay (can all be estimates).

src/Charts/GenericChart.cpp

@@ -439,7 +439,7 @@ GenericChart::finaliseChart()
             }
 
             // did we have a voronoi diagram?
-            if (p.voronoix.count() >= 2) newPlots[i].plot->addVoronoi(p.voronoix, p.voronoiy);
+            if (p.voronoix.count() >= 2) newPlots[i].plot->addVoronoi(p.name, p.voronoix, p.voronoiy);
         }
 
         // set axis

src/Charts/GenericLines.cpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2021 Mark Liversedge (liversedge@gmail.com)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <QChart>
+#include "GenericLines.h"
+
+GenericLines::GenericLines(GenericPlot *plot) : QGraphicsItem(NULL), plot(plot), curve(NULL)
+{
+}
+
+GenericLines::~GenericLines() {}
+
+void
+GenericLines::paint(QPainter*painter, const QStyleOptionGraphicsItem *, QWidget*)
+{
+    if (curve == NULL) return;
+
+    QPen pen(Qt::lightGray);
+    painter->setPen(pen);
+
+    painter->setClipRect(plot->qchart->plotArea());
+
+    foreach(QLineF line, lines) {
+        QPointF from = plot->qchart->mapToPosition(line.p1(), curve);
+        QPointF to = plot->qchart->mapToPosition(line.p2(), curve);
+
+        painter->drawLine(from, to);
+    }
+}
+
+void
+GenericLines::prepare()
+{
+    prepareGeometryChange();
+}
+
+QRectF GenericLines::boundingRect() const
+{
+    // we cover the entire plot area generally
+    return plot->qchart->plotArea();
+}

src/Charts/GenericLines.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2021 Mark Liversedge (liversedge@gmail.com)
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef _GC_GenericLines_h
+#define _GC_GenericLines_h 1
+
+#include <QPointF>
+#include <QtCharts>
+#include <QGraphicsItem>
+
+#include "GenericPlot.h"
+
+// for painting lines on a chart
+class GenericLines : public QGraphicsItem
+{
+
+    Q_INTERFACES(QGraphicsItem)
+
+    public:
+
+        GenericLines(GenericPlot *);
+        ~GenericLines();
+
+        void setCurve(QAbstractSeries *curve) { this->curve=curve; }
+        void setLines(QList<QLineF> lines) { this->lines = lines; update(); }
+
+        void paint(QPainter*, const QStyleOptionGraphicsItem *, QWidget*);
+        QRectF boundingRect() const;
+
+        void prepare();
+    private:
+
+        // lines to draw
+        QList<QLineF> lines;
+        GenericPlot *plot;
+
+        QAbstractSeries *curve;
+
+};
+
+#endif

src/Charts/GenericPlot.cpp

@@ -28,6 +28,9 @@
 #include "ChartSpace.h"
 #include "UserChartOverviewItem.h"
 
+#include "Voronoi.h"
+#include "GenericLines.h"
+
 #include <limits>
 
 // used to format dates/times on axes
@@ -47,6 +50,7 @@ GenericPlot::GenericPlot(QWidget *parent, Context *context, QGraphicsItem *item)
     barseries=NULL;
     stackbarseries=NULL;
     percentbarseries=NULL;
+    voronoidiagram=NULL;
     bottom=left=true;
 
     mainLayout = new QVBoxLayout(this);
@@ -316,12 +320,11 @@ GenericPlot::addAnnotation(AnnotationType, QString string, QColor color)
 }
 
 void
-GenericPlot::addVoronoi(QVector<double>x, QVector<double>y)
+GenericPlot::addVoronoi(QString name, QVector<double>x, QVector<double>y)
 {
+    vname = name;
     vx = x;
     vy = y;
-
-    fprintf(stderr, "generic plot: add voronoi diagram\n"); fflush(stderr);
 }
 
 void
@@ -456,6 +459,8 @@ GenericPlot::plotAreaChanged()
 bool
 GenericPlot::initialiseChart(QString title, int type, bool animate, int legpos, double scale)
 {
+    clearVoronoi();
+
     // if we changed the type, all series must go
     if (charttype != type) {
         qchart->removeAllSeries();
@@ -466,6 +471,7 @@ GenericPlot::initialiseChart(QString title, int type, bool animate, int legpos,
         percentbarseries=NULL;
     }
 
+
     foreach(QLabel *label, labels) delete label;
     labels.clear();
 
@@ -919,6 +925,9 @@ GenericPlot::finaliseChart()
 {
     if (!qchart) return;
 
+    // remove voronoix if present
+    clearVoronoi();
+
     // clear ALL axes
     foreach(QAbstractAxis *axis, qchart->axes(Qt::Vertical)) {
         qchart->removeAxis(axis);
@@ -1246,6 +1255,9 @@ GenericPlot::finaliseChart()
     // add labels after legend items
     foreach(QLabel *label, labels) legend->addLabel(label);
 
+    // add voronoi if need to
+    plotVoronoi();
+
     plotAreaChanged(); // make sure get updated before paint
 }
 
@@ -1357,3 +1369,46 @@ GenericPlot::seriesColor(QAbstractSeries* series)
     default: return GColor(CPLOTMARKER);
     }
 }
+
+void
+GenericPlot::plotVoronoi()
+{
+    // if there is one there already, lets remove it
+    clearVoronoi();
+
+    if (vx.count() < 2) return;
+
+    Voronoi v;
+    for(int i=0; i<vx.count(); i++)  v.addSite(QPointF(vx[i],vy[i]));
+    v.run(QRectF());
+
+#if 0
+    // how many lines?
+    fprintf(stderr, "voronoi diagram curve '%s' has %d lines\n", vname.toStdString().c_str(),v.lines().count()); fflush(stderr);
+
+    foreach(QLineF line, v.lines()) {
+        fprintf(stderr, "from %f,%f to %f,%f\n", line.p1().x(), line.p1().y(), line.p2().x(), line.p2().y());
+    }
+#endif
+
+    // create a new diagram
+    voronoidiagram = new GenericLines(this);
+    voronoidiagram->setCurve(curves.value(vname,NULL));
+    voronoidiagram->setLines(v.lines());
+
+    chartview->scene()->addItem(voronoidiagram);
+    voronoidiagram->update();
+}
+
+void
+GenericPlot::clearVoronoi()
+{
+    if (voronoidiagram) {
+        voronoidiagram->setCurve(NULL);
+        voronoidiagram->setLines(QList<QLineF>());
+        voronoidiagram->prepare();
+        chartview->scene()->removeItem(voronoidiagram);
+        //delete voronoidiagram; // CRASH!
+        voronoidiagram = NULL;
+    }
+}

src/Charts/GenericPlot.h

@@ -58,6 +58,7 @@ class GenericPlot;
 class GenericLegend;
 class GenericSelectTool;
 class GenericAxisInfo;
+class GenericLines; // draw lines
 
 // the chart
 class ChartSpace;
@@ -72,6 +73,7 @@ class GenericPlot : public QWidget {
         static QString gl_timeformat;
 
         friend class GenericSelectTool;
+        friend class GenericLines;
         friend class GenericLegend;
 
         GenericPlot(QWidget *parent, Context *context, QGraphicsItem *item);
@@ -107,7 +109,7 @@ class GenericPlot : public QWidget {
         // adding annotations
         void addAnnotation(AnnotationType, QAbstractSeries*, double yvalue); // LINE
         void addAnnotation(AnnotationType, QString, QColor=QColor(Qt::gray)); // LABEL
-        void addVoronoi(QVector<double>, QVector<double>); // VORONOI
+        void addVoronoi(QString name, QVector<double>, QVector<double>); // VORONOI
 
         // configure axis, after curves added
         bool configureAxis(QString name, bool visible, int align, double min, double max,
@@ -119,6 +121,10 @@ class GenericPlot : public QWidget {
         // do we want to see this series?
         void setSeriesVisible(QString name, bool visible);
 
+        // adding and clearing a voronoi diagram from the chart
+        void clearVoronoi();
+        void plotVoronoi();
+
         // watching scene events and managing interaction
         void seriesClicked(QAbstractSeries*series, GPointF point);
         bool eventHandler(int eventsource, void *obj, QEvent *event);
@@ -126,6 +132,9 @@ class GenericPlot : public QWidget {
         void plotAreaChanged();
         void pieHover(QPieSlice *slice, bool state);
 
+        // access structures
+        QAbstractSeries *curve(QString name) { return curves.value(name, NULL); }
+
     protected:
 
         // legend and selector need acces to these
@@ -153,7 +162,10 @@ class GenericPlot : public QWidget {
 
         // annotations
         QList<QLabel *> labels;
+
+        QString vname;
         QVector<double> vx, vy; //voronoi digram
+        GenericLines *voronoidiagram; // draws the lines on the chart
 
     private:
         Context *context;

src/Charts/UserChart.cpp

@@ -180,6 +180,10 @@ UserChart::setRide(const RideItem *item)
         // clear old annotations for this series
         annotations.clear();
 
+        // any old voronoi diagram centers
+        series.voronoix.clear();
+        series.voronoiy.clear();
+
         // re-create program (may be edited)
         if (series.user1 != NULL) delete static_cast<UserChartData*>(series.user1);
         series.user1 = new UserChartData(context, this, series.string1, rangemode);
@@ -534,7 +538,7 @@ UserChart::annotateVoronoi(QVector<double>x, QVector<double>y)
             UserChartData *ucd = static_cast<UserChartData*>(seriesinfo[i].user1);
             if (ucd->program == from) {
                 seriesinfo[i].voronoix = x;
-                seriesinfo[i].voronoiy = x;
+                seriesinfo[i].voronoiy = y;
             }
         }
     }

src/src.pro

@@ -655,9 +655,9 @@ greaterThan(QT_MAJOR_VERSION, 4) {
         # generic chart
         DEFINES += GC_HAVE_GENERIC
         HEADERS += Charts/UserChartWindow.h Charts/UserChartOverviewItem.h Charts/UserChart.h Charts/UserChartData.h \
-                   Charts/GenericChart.h Charts/GenericPlot.h Charts/GenericSelectTool.h Charts/GenericLegend.h
+                   Charts/GenericChart.h Charts/GenericPlot.h Charts/GenericSelectTool.h Charts/GenericLegend.h Charts/GenericLines.h
         SOURCES += Charts/UserChartWindow.cpp Charts/UserChartOverviewItem.cpp Charts/UserChart.cpp Charts/UserChartData.cpp \
-                   Charts/GenericChart.cpp Charts/GenericPlot.cpp Charts/GenericSelectTool.cpp Charts/GenericLegend.cpp
+                   Charts/GenericChart.cpp Charts/GenericPlot.cpp Charts/GenericSelectTool.cpp Charts/GenericLegend.cpp Charts/GenericLines.cpp
 
     }
 }