improved step plots (JKQTPstepHorizontalGraph, JKQTPstepVerticalGraph) with 3 step-modes (left/center/right), instead of only two (right/center)

added example for step plots

README.md

@@ -20,8 +20,9 @@ All test-projects are Qt-projects that use qmake to build. You can load them int
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest1_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest) | [Very Basic Example (Line Graph)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest) | `JKQTPxyLineGraph`<br/>C++-style QVector arrays of data |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_speed_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_speed) | [Line Graph with Live Data / Speed Test](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_speed) | `JKQTPxyLineGraph`<br/>external `std::array<double,N>` data, not owned by datastore<br/>live-data, measure plotting speed<br/>tipps to increas plotting speed |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_symbols_and_styles_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_symbols_and_styles) | [Line Graph with Different Symbols and Line Styles](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_symbols_and_styles) | `JKQTPxyLineGraph`<br/>C++ vector of data<br/>setting line styles and symbol styles<br/>automatic graph coloring |
-| [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_symbols_and_errors_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_symbols_and_errors) | [Simple Line/Symbol Graph With Errorbars](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_symbols_and_errors) | `JKQTPxyLineErrorGraph`<br/>C-style arrays of data |
+| [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_stepplots_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_stepplots) | [Step Line Plots in Different Styles](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_stepplots) | `JKQTPxyLineGraph`<br/>C++ vector of data<br/>setting line styles and symbol styles<br/>automatic graph coloring |
-| [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_errorbarstyles) | [Different Types of Errorindicators](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_errorbarstyles) | `JKQTPxyLineErrorGraph`<br/>different styles of error indicators for x- and y-errors<br>C++-style QVector for data<br/>styling error indicators<br/>moving key and formatting plotter grid |
+| [Simple Line/Symbol Graph With Errorbars](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_symbols_and_errors) | `JKQTPxyLineErrorGraph`<br/>C-style arrays of data |
+| [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_errorbarstyles) | [Different Types of Error Indicators](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_errorbarstyles) | `JKQTPxyLineErrorGraph`<br/>different styles of error indicators for x- and y-errors<br>C++-style QVector for data<br/>styling error indicators<br/>moving key and formatting plotter grid |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_barchart_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_barchart) | [Simple Bar Charts](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_barchart) | `JKQTPbarVerticalGraph`<br/>C-style arrays of data |
 | [![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/JKQTPbarVerticalGraphStacked_small.png)<br>![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/JKQTPbarHorizontalGraphStacked_small.png)](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_stackedbars) | [Stacked Bar Charts](https://github.com/jkriege2/JKQtPlotter/tree/master/test/jkqtplotter_simpletest_stackedbars) | `JKQTPbarVerticalStackableGraph`, `JKQTPbarHorizontalStackableGraph`<br/>C++-style vectors of data |
 

lib/jkqtplotter/jkqtpelements.cpp

@@ -540,7 +540,7 @@ JKQTPstepHorizontalGraph::JKQTPstepHorizontalGraph(JKQtBasePlotter* parent):
     fillStyle=Qt::SolidPattern;
     drawLine=true;
     fillCurve=true;
-    valuesCentered=false;
+    stepType=JKQTPstepLeft;
 
 
     if (parent) { // get style settings from parent object
@@ -563,7 +563,7 @@ JKQTPstepHorizontalGraph::JKQTPstepHorizontalGraph(JKQtPlotter* parent):
     fillStyle=Qt::SolidPattern;
     drawLine=true;
     fillCurve=true;
-    valuesCentered=false;
+    stepType=JKQTPstepLeft;
 
 
     if (parent) { // get style settings from parent object
@@ -650,8 +650,8 @@ void JKQTPstepHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
 //    double ystart=-1;
     double x0=xAxis->x2p(0);
     if (parent->getXAxis()->isLogAxis()) x0=xAxis->x2p(parent->getXAxis()->getMin());
-//    double y0=yAxis->x2p(0);
+    double y0=yAxis->x2p(0);
-//    if (parent->getYAxis()->isLogAxis()) y0=yAxis->x2p(parent->getYAxis()->getMin());
+    if (parent->getYAxis()->isLogAxis()) y0=yAxis->x2p(parent->getYAxis()->getMin());
     bool subsequentItem=false;
     intSortData();
     for (int iii=imin; iii<imax; iii++) {
@@ -668,7 +668,7 @@ void JKQTPstepHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
                 //double xl2=x;
                 //double yl2=y;
 
-                if (valuesCentered) {
+                if (stepType==JKQTPstepCenter) {
                     double d=(x-xold);
                     pf.lineTo(xold+d/2.0, yold);
                     pf.lineTo(xold+d/2.0, y);
@@ -678,7 +678,14 @@ void JKQTPstepHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
                         pl.lineTo(xold+d/2.0, y);
                         pl.lineTo(x, y);
                     }
-                } else {
+                } else if (stepType==JKQTPstepLeft) {
+                    pf.lineTo(xold, y);
+                    pf.lineTo(x, y);
+                    if (drawLine) {
+                        pl.lineTo(xold, y);
+                        pl.lineTo(x, y);
+                    }
+                } else if (stepType==JKQTPstepRight) {
                     pf.lineTo(x, yold);
                     pf.lineTo(x, y);
                     if (drawLine) {
@@ -690,7 +697,7 @@ void JKQTPstepHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
                 //std::cout<<"line ("<<xl1<<", "<<yl1<<") -- ("<<xl2<<", "<<yl2<<")"<<std::endl;
             } else {
                 if (drawLine) pl.moveTo(x,y);
-                pf.moveTo(x0, y);
+                pf.moveTo(x, y0);
                 pf.lineTo(x, y);
                 //xstart=x;
                 //ystart=y0;
@@ -701,7 +708,7 @@ void JKQTPstepHorizontalGraph::draw(JKQTPEnhancedPainter& painter) {
         }
     }
     if (fillCurve) {
-        pf.lineTo(x0, yold);
+        pf.lineTo(xold, y0);
         pf.closeSubpath();
     }
     painter.save();
@@ -784,8 +791,8 @@ void JKQTPstepVerticalGraph::draw(JKQTPEnhancedPainter& painter) {
 
     double xold=-1;
     double yold=-1;
-//    double x0=xAxis->x2p(0);
+    double x0=xAxis->x2p(0);
-//    if (parent->getXAxis()->isLogAxis()) x0=xAxis->x2p(parent->getXAxis()->getMin());
+    if (parent->getXAxis()->isLogAxis()) x0=xAxis->x2p(parent->getXAxis()->getMin());
     double y0=yAxis->x2p(0);
     if (parent->getYAxis()->isLogAxis()) y0=yAxis->x2p(parent->getYAxis()->getMin());
     bool first=false;
@@ -804,7 +811,7 @@ void JKQTPstepVerticalGraph::draw(JKQTPEnhancedPainter& painter) {
                 //double xl2=x;
                 //double yl2=y;
 
-                if (valuesCentered) {
+                if (stepType==JKQTPstepCenter) {
                     double d=(y-yold);
                     pf.lineTo(xold, yold+d/2.0);
                     pf.lineTo(x, yold+d/2.0);
@@ -814,7 +821,14 @@ void JKQTPstepVerticalGraph::draw(JKQTPEnhancedPainter& painter) {
                         pl.lineTo(x, yold+d/2.0);
                         pl.lineTo(x, y);
                     }
-                } else {
+                } else if (stepType==JKQTPstepLeft) {
+                    pf.lineTo(x, yold);
+                    pf.lineTo(x, y);
+                    if (drawLine) {
+                        pl.lineTo(x, yold);
+                        pl.lineTo(x, y);
+                    }
+                } else if (stepType==JKQTPstepRight) {
                     pf.lineTo(xold, y);
                     pf.lineTo(x, y);
                     if (drawLine) {
@@ -826,7 +840,7 @@ void JKQTPstepVerticalGraph::draw(JKQTPEnhancedPainter& painter) {
                 //std::cout<<"line ("<<xl1<<", "<<yl1<<") -- ("<<xl2<<", "<<yl2<<")"<<std::endl;
             } else {
                 if (drawLine) pl.moveTo(x,y);
-                pf.moveTo(x, y0);
+                pf.moveTo(x0, y);
                 pf.lineTo(x, y);
             }
             xold=x;
@@ -834,7 +848,7 @@ void JKQTPstepVerticalGraph::draw(JKQTPEnhancedPainter& painter) {
             first=true;
         }
     }
-    pf.lineTo(xold, y0);
+    pf.lineTo(x0, yold);
     pf.closeSubpath();
     painter.save();
     if (drawLine) {

lib/jkqtplotter/jkqtpelements.h

@@ -397,7 +397,7 @@ class LIB_EXPORT JKQTPstepHorizontalGraph: public JKQTPxyGraph {
         JKQTPGET_SET_MACRO(double, lineWidth)
         JKQTPGET_SET_MACRO(bool, drawLine)
         JKQTPGET_SET_MACRO(bool, fillCurve)
-        JKQTPGET_SET_MACRO(bool, valuesCentered)
+        JKQTPGET_SET_MACRO(JKQTPstepType, stepType)
     protected:
         /** \brief color of the graph */
         QColor color;
@@ -413,8 +413,8 @@ class LIB_EXPORT JKQTPstepHorizontalGraph: public JKQTPxyGraph {
         bool drawLine;
         /** \brief indicates whether to fill the space between the curve and the x-axis */
         bool fillCurve;
-        /** \brief The steps are centered around the \f$ x_i \f$ values, if this is true. */
+        /** \brief specifies whether the steps elongate to the left, the right, or are centered around the \f$ x_i \f$ values. */
-        bool valuesCentered;
+        JKQTPstepType stepType;
 
         /** \brief which plot style to use from the parent plotter (via JKQtPlotterBase::getPlotStyle() and JKQtPlotterBase::getNextStyle() ) */
         int parentPlotStyle;

lib/jkqtplottertools/jkqtptools.cpp

@@ -2204,3 +2204,56 @@ std::string jkqtp_chartostr(char data){
   ost<<data;
   return ost.str();
 }
+
+JKQTPstepTypeComboBox::JKQTPstepTypeComboBox(QWidget *parent):
+    QComboBox(parent)
+{
+    clear();
+    setEditable(false);
+    addStep(JKQTPstepType::JKQTPstepLeft, JKQTPstepType2String(JKQTPstepType::JKQTPstepLeft));
+    addStep(JKQTPstepType::JKQTPstepCenter, JKQTPstepType2String(JKQTPstepType::JKQTPstepCenter));
+    addStep(JKQTPstepType::JKQTPstepRight, JKQTPstepType2String(JKQTPstepType::JKQTPstepRight));
+    setCurrentIndex(0);
+}
+
+JKQTPstepType JKQTPstepTypeComboBox::getStepType() const
+{
+    return String2JKQTPstepType(itemData(currentIndex()).toString());
+}
+
+void JKQTPstepTypeComboBox::setStepType(JKQTPstepType step)
+{
+    int i=findData(JKQTPstepType2String(step));
+    if (i>=0) setCurrentIndex(i);
+}
+
+void JKQTPstepTypeComboBox::setCurrentStepType(JKQTPstepType step)
+{
+    setStepType(step);
+}
+
+void JKQTPstepTypeComboBox::addStep(JKQTPstepType step, const QString &name, const QIcon &icon)
+{
+    addItem(icon, name, JKQTPstepType2String(step));
+}
+
+QString JKQTPstepType2String(JKQTPstepType pos)
+{
+    switch(pos) {
+        case JKQTPstepLeft: return "step_left";
+        case JKQTPstepCenter: return "step_center";
+        case JKQTPstepRight: return "step_right";
+    }
+    return "";
+}
+
+JKQTPstepType String2JKQTPstepType(QString pos)
+{
+    QString s=pos.trimmed().toLower();
+    if (s=="step_left"||s=="left"||s=="l") return JKQTPstepLeft;
+    if (s=="step_center"||s=="center"||s=="c") return JKQTPstepCenter;
+    if (s=="step_right"||s=="right"||s=="r") return JKQTPstepRight;
+
+    return JKQTPstepLeft;
+}
+

lib/jkqtplottertools/jkqtptools.h

@@ -1346,4 +1346,44 @@ template<>
 inline constexpr double jkqtp_todouble(const bool& d) {
     return static_cast<double>((d)?1.0:0.0);
 }
+
+
+
+
+/** \brief plot styles for the error information
+ * \ingroup jkqtplotter
+ */
+enum JKQTPstepType {
+    JKQTPstepLeft=0,           /*!< \brief datapoint is on the left edge of the hor. step line */
+    JKQTPstepCenter=1,           /*!< \brief datapoint is centered on the hor. step line */
+    JKQTPstepRight=2,         /*!< \brief datapoint is on the right edge of the hor. step line */
+};
+
+/*! \brief a QComboBox which shows JKQTPstepType
+    \ingroup jkqtptools
+ */
+class LIB_EXPORT JKQTPstepTypeComboBox: public QComboBox {
+        Q_OBJECT
+    public:
+        JKQTPstepTypeComboBox(QWidget* parent=nullptr);
+
+        JKQTPstepType getStepType() const;
+        void setStepType(JKQTPstepType step);
+        void setCurrentStepType(JKQTPstepType step);
+    protected:
+        void addStep(JKQTPstepType step, const QString& name, const QIcon &icon=QIcon());
+};
+
+
+
+/** \brief converts a JKQTPstepType variable into a human-readable string
+ * \ingroup jkqtptools
+ */
+LIB_EXPORT QString JKQTPstepType2String(JKQTPstepType pos);
+
+/** \brief converts a String into a JKQTPstepType
+ * \ingroup jkqtptools
+ */
+LIB_EXPORT JKQTPstepType String2JKQTPstepType(QString pos);
+
 #endif // JKQTPTOOLS_H_INCLUDED

test/jkqtplotter_simpletest/README.md

@@ -9,6 +9,30 @@ The QMake project looks like this (see `./test/jkqtplotter_simpletest/jkqtplotte
 # source code for this simple demo
 SOURCES = jkqtplotter_simpletest.cpp 
 
+# configure Qt
+CONFIG += qt
+QT += core gui xml svg
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
+
+# output executable name
+TARGET = jkqtplotter_simpletest
+
+# include JKQtPlotter source headers and link against library
+DEPENDPATH += . ../../lib
+INCLUDEPATH += ../../lib
+CONFIG (debug, debug|release):LIBS += -L../../lib/debug -ljkqtplotterlib
+CONFIG (release):LIBS += -L../../lib/release -ljkqtplotterlib
+
+# here you can activate some debug options
+#DEFINES += SHOW_JKQTPLOTTER_DEBUG
+#DEFINES += JKQTBP_AUTOTIMER
+```
+
+Alternatively to linking agains a `libjkqtplotter`, you can also directy add the JKQtPlotter sources to the project:
+```qmake
+# source code for this simple demo
+SOURCES = jkqtplotter_simpletest.cpp 
+
 # configure Qt
 CONFIG += qt
 QT += core gui svg
@@ -20,7 +44,7 @@ TARGET = jkqtplotter_simpletest
 # include JKQtPlotter source code
 include(../../lib/jkqtplotter.pri)
 ```
-And the soruce code of the main application is (see `./test/jkqtplotter_simpletest/jkqtplotter_simpletest.cpp`):
+The soruce code of the main application is (see `./test/jkqtplotter_simpletest/jkqtplotter_simpletest.cpp`):
 ```c++
 #include <QApplication>
 #include "jkqtplotter/jkqtplotter.h"

test/jkqtplotter_simpletest/jkqtplotter_simpletest.pro

@@ -9,7 +9,7 @@ greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
 # output executable name
 TARGET = jkqtplotter_simpletest
 
-# include JKQtPlotter source code
+# include JKQtPlotter source headers and link against library
 DEPENDPATH += . ../../lib
 INCLUDEPATH += ../../lib
 CONFIG (debug, debug|release):LIBS += -L../../lib/debug -ljkqtplotterlib

test/jkqtplotter_simpletest_rgbimageplot_qt/README.md

@@ -2,8 +2,8 @@
 
 # JKQtPlotter
 
-## Simple RGB image plot, showing a 3-channel OpenCV cv::Mat
+## `QImage` as a Graph
-This project (see `./test/jkqtplotter_simpletest_rgbimageplot_qt/`) simply creates a JKQtPlotter widget (as a new window) and adds an image plot with an image taken from a QImage object. 
+This project (see `./test/jkqtplotter_simpletest_rgbimageplot_qt/`) simply creates a JKQtPlotter widget (as a new window) and adds an image plot with an image taken from a [QImage](http://doc.qt.io/qt-5/qimage.html) object. 
 
 The source code of the main application is (see `./test/jkqtplotter_simpletest_rgbimageplot_qt/jkqtplotter_simpletest_rgbimageplot_qt.cpp`). the main parts are:
 ```c++

test/jkqtplotter_simpletest_stepplots/README.md

@@ -0,0 +1,58 @@
+[Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/)
+
+# JKQtPlotter
+
+## Step Line Plots in Different Styles
+This project (see `./test/jkqtplotter_simpletest_stepplots/`) simply creates a JKQtPlotter widget (as a new window) and adds a single line-graph (a sine-wave). Data is initialized from two QVector<double> objects.
+
+The source code of the main application can be found in  [`jkqtplotter_simpletest_stepplots.cpp`](https://github.com/jkriege2/JKQtPlotter/blob/master/test/jkqtplotter_simpletest_stepplots/jkqtplotter_simpletest_stepplots.cpp). For the most part, several datasets of cosine-curves are generated. then thrre tuples of graphs are added: One of type `JKQTPxyLineGraph`, which simply indicates the location of the actual datapoints. the second is of type `JKQTPstepHorizontalGraph`, which adds the step-graph to the plot:
+
+```c++
+	// 3 now we make several plots with different step styles, each one also contains a
+    //     symbol plot indicating the location of the datapoints themselves
+    JKQTPstepHorizontalGraph* graph;
+    JKQTPxyLineGraph* graphL;
+
+    //-- JKQTPstepLeft ----------------------------------------------------------------------------------------
+    graph=new JKQTPstepHorizontalGraph(&plot);
+    graphL=new JKQTPxyLineGraph(&plot);
+
+    // set data for both graphs
+    graph->set_xColumn(columnX); graphL->set_xColumn(graph->get_xColumn());
+    graph->set_yColumn(columnY1); graphL->set_yColumn(graph->get_yColumn());
+
+    // set step style
+    graph->set_stepType(JKQTPstepLeft);
+    graph->set_lineWidth(1);
+    graph->set_fillCurve(true);
+    graph->set_drawLine(true);
+    graph->set_title("JKQTPstepLeft, filled");
+```
+Note that you can configure the step type (left/center/right by `graph->set_stepType(JKQTPstepLeft)`. With `graph->set_fillCurve(true)` you can draw the curve filled until the y=0-axis and with `graph->set_drawLine(true)` you can switch the line along the values on and off (e.g. to only have the filled area, but no line).
+
+Finally the `JKQTPxyLineGraph` is configured:
+```c++
+    // set symbol + pen style and color for the added circles, copy color
+    graphL->set_symbol(JKQTPgraphSymbols::JKQTPcircle);
+    graphL->set_drawLine(false);
+    graphL->set_symbolSize(9);
+    graphL->set_symbolWidth(1);
+    graphL->set_color(graph->get_color());
+```
+
+... and all graphs are added to the plot:
+```c++
+    // add the graphs to the plot, so it is actually displayed
+    plot.addGraph(graph);
+    plot.addGraph(graphL);
+```
+
+In addition to the symbol type and line style, you can also alter the size of the symbols (`graph->set_symbolSize(14)`), the line-width used to draw them (`graph->set_symbolWidth(1.5)`) and the line width of the graph line (`graph->set_lineWidth(1)`). If you want to switch off the line altogether, use `graph->set_drawLine(false`.
+
+The result looks like this:
+
+![jkqtplotter_simpletest_stepplots](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_stepplots.png)
+
+
+
+[Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/)

test/jkqtplotter_simpletest_stepplots/jkqtplotter_simpletest_stepplots.cpp

@@ -0,0 +1,126 @@
+#include <QApplication>
+#include "jkqtplotter/jkqtplotter.h"
+#include "jkqtplottertools/jkqtptools.h"
+
+int main(int argc, char* argv[])
+{
+    QApplication app(argc, argv);
+
+    // 1. create a plotter window and get a pointer to the internal datastore (for convenience)
+    JKQtPlotter plot;
+    JKQTPdatastore* ds=plot.getDatastore();
+
+    // 2. now we create data a vector of x-values for a simple plot and several sets of y-values for
+    //    cosine curves stacked above each other
+    QVector<double> X, Y1, Y2, Y3;
+    const int Ndata=10; // number of plot points in each curve
+    for (int i=0; i<Ndata; i++) {
+        const double x=double(i)/double(Ndata)*2.0*M_PI;
+        X<<x;
+        Y1<<cos(x)+1.0*1.5;
+        Y2<<cos(x)+2.0*1.5;
+        Y3<<cos(x)+3.0*1.5;
+    }
+    // and copy it to the datastore
+    size_t columnX=ds->addCopiedColumn(X, "x");
+    size_t columnY1=ds->addCopiedColumn(Y1, "y1");
+    size_t columnY2=ds->addCopiedColumn(Y2, "y2");
+    size_t columnY3=ds->addCopiedColumn(Y3, "y3");
+
+    // 3 now we make several plots with different step styles, each one also contains a
+    //     symbol plot indicating the location of the datapoints themselves
+    JKQTPstepHorizontalGraph* graph;
+    JKQTPxyLineGraph* graphL;
+
+    //-- JKQTPstepLeft ----------------------------------------------------------------------------------------
+    graph=new JKQTPstepHorizontalGraph(&plot);
+    graphL=new JKQTPxyLineGraph(&plot);
+
+    // set data for both graphs
+    graph->set_xColumn(columnX); graphL->set_xColumn(graph->get_xColumn());
+    graph->set_yColumn(columnY1); graphL->set_yColumn(graph->get_yColumn());
+
+    // set step style
+    graph->set_stepType(JKQTPstepLeft);
+    graph->set_lineWidth(1);
+    graph->set_fillCurve(true);
+    graph->set_drawLine(true);
+    graph->set_title("JKQTPstepLeft, filled");
+
+    // set symbol + pen style and color for the added circles, copy color
+    graphL->set_symbol(JKQTPgraphSymbols::JKQTPcircle);
+    graphL->set_drawLine(false);
+    graphL->set_symbolSize(9);
+    graphL->set_symbolWidth(1);
+    graphL->set_color(graph->get_color());
+
+    // add the graphs to the plot, so it is actually displayed
+    plot.addGraph(graph);
+    plot.addGraph(graphL);
+
+
+    //-- JKQTPstepCenter ----------------------------------------------------------------------------------------
+    graph=new JKQTPstepHorizontalGraph(&plot);
+    graphL=new JKQTPxyLineGraph(&plot);
+
+    // set data for both graphs
+    graph->set_xColumn(columnX); graphL->set_xColumn(graph->get_xColumn());
+    graph->set_yColumn(columnY2); graphL->set_yColumn(graph->get_yColumn());
+
+    // set step style
+    graph->set_stepType(JKQTPstepCenter);
+    graph->set_lineWidth(1);
+    graph->set_fillCurve(false);
+    graph->set_drawLine(true);
+    graph->set_title("JKQTPstepCenter");
+
+    // set symbol + pen style and color for the added circles, copy color
+    graphL->set_symbol(JKQTPgraphSymbols::JKQTPcircle);
+    graphL->set_drawLine(false);
+    graphL->set_symbolSize(9);
+    graphL->set_symbolWidth(1);
+    graphL->set_color(graph->get_color());
+
+    // add the graphs to the plot, so it is actually displayed
+    plot.addGraph(graph);
+    plot.addGraph(graphL);
+
+
+    //-- JKQTPstepRight ----------------------------------------------------------------------------------------
+    graph=new JKQTPstepHorizontalGraph(&plot);
+    graphL=new JKQTPxyLineGraph(&plot);
+
+    // set data for both graphs
+    graph->set_xColumn(columnX); graphL->set_xColumn(graph->get_xColumn());
+    graph->set_yColumn(columnY3); graphL->set_yColumn(graph->get_yColumn());
+
+    // set step style
+    graph->set_stepType(JKQTPstepRight);
+    graph->set_lineWidth(1);
+    graph->set_fillCurve(false);
+    graph->set_drawLine(true);
+    graph->set_title("JKQTPstepRight");
+
+    // set symbol + pen style and color for the added circles, copy color
+    graphL->set_symbol(JKQTPgraphSymbols::JKQTPcircle);
+    graphL->set_drawLine(false);
+    graphL->set_symbolSize(9);
+    graphL->set_symbolWidth(1);
+    graphL->set_color(graph->get_color());
+
+    // add the graphs to the plot, so it is actually displayed
+    plot.addGraph(graph);
+    plot.addGraph(graphL);
+
+
+
+
+    // 4. scale plot manually
+    plot.setXY(-0.5, X.last()+0.5, -0.5, 7);
+
+    // 5. show plotter and make it a decent size
+    plot.show();
+    plot.resize(800,600);
+
+    return app.exec();
+}

test/jkqtplotter_simpletest_stepplots/jkqtplotter_simpletest_stepplots.pro

@@ -0,0 +1,22 @@
+# source code for this simple demo
+SOURCES = jkqtplotter_simpletest_stepplots.cpp 
+
+# configure Qt
+CONFIG += qt
+QT += core gui xml  svg
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets printsupport
+
+# output executable name
+TARGET = jkqtplotter_simpletest_stepplots
+
+
+# include JKQtPlotter source code
+DEPENDPATH += . ../../lib
+INCLUDEPATH += ../../lib
+CONFIG (debug, debug|release):LIBS += -L../../lib/debug -ljkqtplotterlib
+CONFIG (release):LIBS += -L../../lib/release -ljkqtplotterlib
+
+
+# here you can activate some debug options
+#DEFINES += SHOW_JKQTPLOTTER_DEBUG
+#DEFINES += JKQTBP_AUTOTIMER

test/jkqtplotter_simpletest_stepplots/jkqtplotter_simpletest_stepplots_and_lib.pro

@@ -0,0 +1,8 @@
+TEMPLATE = subdirs
+
+SUBDIRS +=  jkqtplotterlib jkqtplotter_simpletest_stepplots
+
+jkqtplotterlib.file = ../../lib/jkqtplotterlib.pro
+
+jkqtplotter_simpletest_stepplots.file=$$PWD/jkqtplotter_simpletest_stepplots.pro
+jkqtplotter_simpletest_stepplots.depends = jkqtplotterlib