/*!

       
  \defgroup jkqtplotter_graphsgroup_classstructure Graphs
  \ingroup jkqtplotter_general

  \section jkqtplotter_graphsgroup_classstructure_basics Graph Class Structure

  Each type of graph is represented by another class, which has to be derived from JKQTPPlotElement. This class provides a basic virtual interface
  that allows JKQTPlotter to draw the graphs represented by them. This interface consists of these functions:
    - JKQTPPlotElement::draw() draws the graph onto a given JKQTPEnhancedPainter (derived from <a href="http://doc.qt.io/qt-5/qpainter.html">QPainter</a>)
    - JKQTPPlotElement::drawKeyMarker() draws the small marker image in the plot legend
    - JKQTPPlotElement::getKeyLabelColor() returns a color for the legend entry for the graph
    - JKQTPPlotElement::getXMinMax() returns the extent of the graph in x-direction (e.g. for auto-zooming)
    - JKQTPPlotElement::getYMinMax() returns the extent of the graph in Y-direction (e.g. for auto-zooming)
  .
  In addition to these basic functions, there are additional functions that can be used to draw something outside the actual plot rectangle.
  These are used to e.g. add color-scales to the side of the graph:
    - JKQTPPlotElement::getOutsideSize() returns the amount of space required outside the plot rectangle
    - JKQTPPlotElement::drawOutside() draws the elements outside the plot rectangle
  .

  Usually if writing a new graph, one would not directly
  derive from JKQTPPlotElement, but from a cass in it's hirarchy of children. These children already provide certain facilities for certain types of graphs.

  \dot
    digraph
    {
     // LATEX_PDF_SIZE
      bgcolor="transparent";
      edge [fontname="FreeSans",fontsize="10",labelfontname="FreeSans",labelfontsize="10"];
      node [fontname="FreeSans",fontsize="10"];
      rankdir="LR";

      {
        rank=same;
        JKQTPPlotElement [URL="\ref JKQTPPlotElement"];
        noteJKQTPPlotElement [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nelements drawn\nonto a plot"];
        JKQTPPlotElement -> noteJKQTPPlotElement [style=dashed,arrowhead=none];
      }

      {
        rank=same;
        JKQTPGraph [URL="\ref JKQTPPlotElement"];
        noteJKQTPGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nactual graphs"];
        JKQTPGraph -> noteJKQTPGraph [style=dashed,arrowhead=none];
      
        JKQTPGeometricPlotElement [URL="\ref JKQTPGeometricPlotElement"];
        noteJKQTPGeometricPlotElement [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nnon-graph elements,\ne.g. geometric elements"];
        JKQTPGeometricPlotElement -> noteJKQTPGeometricPlotElement [style=dashed,arrowhead=none];
      
        JKQTPPlotAnnotationElement [URL="\ref JKQTPPlotAnnotationElement"];
        noteJKQTPPlotAnnotationElement [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraph annotation elements,\ne.g. text, symbols, ranges ..."];
        JKQTPPlotAnnotationElement -> noteJKQTPPlotAnnotationElement [style=dashed,arrowhead=none];
      }


      {
        rank=same;

        JKQTPXYGraph [URL="\ref JKQTPXYGraph"]
        noteJKQTPXYGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on\n (x,y) data pairs"];
        JKQTPXYGraph -> noteJKQTPXYGraph [style=dashed,arrowhead=none];
      
        JKQTPXGraph [URL="\ref JKQTPXGraph"]
        noteJKQTPXGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on\n (x,....) data e.g. JKQTPFinancialGraph"];
        JKQTPXGraph -> noteJKQTPXGraph [style=dashed,arrowhead=none];
      
        JKQTPSingleColumnGraph [URL="\ref JKQTPSingleColumnGraph"]
        noteJKQTPSingleColumnGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on only\n a single column of data"];
        JKQTPSingleColumnGraph -> noteJKQTPSingleColumnGraph [style=dashed,arrowhead=none];
      
        JKQTPImageBase [URL="\ref JKQTPImageBase"]
        noteJKQTPImageBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs that represent \n2D images/matrices"];
        JKQTPImageBase -> noteJKQTPImageBase [style=dashed,arrowhead=none];
      }

      {
        rank=same;

        JKQTPXYYGraph [URL="\ref JKQTPXYYGraph"]
        noteJKQTPXYYGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on\n (x, y1, y2) data triples"];
        JKQTPXYYGraph -> noteJKQTPXYYGraph [style=dashed,arrowhead=none];

        JKQTPXXYGraph [URL="\ref JKQTPXXYGraph"]
        noteJKQTPXXYGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on\n (x1, x2, y) data triples"];
        JKQTPXXYGraph -> noteJKQTPXXYGraph [style=dashed,arrowhead=none];

        JKQTPXYAndVectorGraph [URL="\ref JKQTPXYAndVectorGraph"]
        noteJJKQTPXYAndVectorGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nvector field graphs based on\n (x, y, dx, dy) data quadruples"];
        JKQTPXYAndVectorGraph -> noteJJKQTPXYAndVectorGraph [style=dashed,arrowhead=none];

        JKQTPXYBaselineGraph [URL="\ref JKQTPXYBaselineGraph"]
        noteJJKQTPXYBaselineGraph [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs based on\n (x,y) data pairs and a baseline"];
        JKQTPXYBaselineGraph -> noteJJKQTPXYBaselineGraph [style=dashed,arrowhead=none];
      
        JKQTPEvaluatedFunctionGraphBase [URL="\ref JKQTPEvaluatedFunctionGraphBase"]
        noteJKQTPEvaluatedFunctionGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs that represent \ndynamically evaluated functions"];
        JKQTPEvaluatedFunctionGraphBase -> noteJKQTPEvaluatedFunctionGraphBase [style=dashed,arrowhead=none];
      
        JKQTPMathImageBase [URL="\ref JKQTPMathImageBase"]
        noteJKQTPMathImageBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ndata-based images"];
        JKQTPMathImageBase -> noteJKQTPMathImageBase [style=dashed,arrowhead=none];
      }  

      {
        rank=same;

        JKQTPBarGraphBase [URL="\ref JKQTPBarGraphBase"]
        noteJKQTPBarGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nbarcharts"];
        JKQTPBarGraphBase -> noteJKQTPBarGraphBase [style=dashed,arrowhead=none];

        JKQTPFilledCurveGraphBase [URL="\ref JKQTPFilledCurveGraphBase"]
        noteJKQTPFilledCurveGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nfilled graphs"];
        JKQTPFilledCurveGraphBase -> noteJKQTPFilledCurveGraphBase [style=dashed,arrowhead=none];

        JKQTPImpulsesGraphBase [URL="\ref JKQTPImpulsesGraphBase"]
        noteJKQTPImpulsesGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nimpulse graphs"];
        JKQTPImpulsesGraphBase -> noteJKQTPImpulsesGraphBase [style=dashed,arrowhead=none];
      
        JKQTPSpecialLineGraphBase [URL="\ref JKQTPSpecialLineGraphBase"]
        noteJKQTPSpecialLineGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nspecial line graphs"];
        JKQTPSpecialLineGraphBase -> noteJKQTPSpecialLineGraphBase [style=dashed,arrowhead=none];
      
        JKQTPBoxplotGraphBase [URL="\ref JKQTPBoxplotGraphBase"]
        noteJKQTPBoxplotGraphBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs that represent \na set of boxplots"];
        JKQTPBoxplotGraphBase -> noteJKQTPBoxplotGraphBase [style=dashed,arrowhead=none];
      
        JKQTPRangeBase [URL="\ref JKQTPRangeBase"];
        noteJKQTPRangeBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\nrange annotations"];
        JKQTPRangeBase -> noteJKQTPRangeBase [style=dashed,arrowhead=none];
      
        JKQTPBoxplotElementBase [URL="\ref JKQTPBoxplotElementBase"]
        noteJKQTPBoxplotElementBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs that represent \na single boxplot"];
        JKQTPBoxplotElementBase -> noteJKQTPBoxplotElementBase [style=dashed,arrowhead=none];
      
        JKQTPViolinplotElementBase [URL="\ref JKQTPViolinplotElementBase"]
        noteJKQTPViolinplotElementBase [shape="note", color="lightyellow",style=filled,fontsize=8,label="base class for all\ngraphs that represent \na single violin plot"];
        JKQTPViolinplotElementBase -> noteJKQTPViolinplotElementBase [style=dashed,arrowhead=none];
      }  
      
      JKQTPPlotElement -> JKQTPGraph
      JKQTPPlotElement -> JKQTPGeometricPlotElement
      JKQTPPlotElement -> JKQTPPlotAnnotationElement
      JKQTPPlotElement -> JKQTPRangeBase
      JKQTPPlotElement -> JKQTPBoxplotElementBase
      JKQTPPlotElement -> JKQTPViolinplotElementBase

      JKQTPGraph -> JKQTPXYGraph
      JKQTPGraph -> JKQTPXGraph
      JKQTPGraph -> JKQTPSingleColumnGraph
      JKQTPGraph -> JKQTPImageBase -> JKQTPMathImageBase
      JKQTPGraph -> JKQTPEvaluatedFunctionGraphBase
      JKQTPGraph -> JKQTPBoxplotGraphBase

      JKQTPXYGraph -> JKQTPXYYGraph
      JKQTPXYGraph -> JKQTPXXYGraph
      JKQTPXYGraph -> JKQTPXYBaselineGraph
      JKQTPXYGraph -> JKQTPXYAndVectorGraph
      
      JKQTPXYBaselineGraph -> JKQTPBarGraphBase
      JKQTPXYBaselineGraph -> JKQTPFilledCurveGraphBase
      JKQTPXYBaselineGraph -> JKQTPImpulsesGraphBase
      JKQTPXYBaselineGraph -> JKQTPSpecialLineGraphBase

    }
  
  \enddot

  \section jkqtplotter_graphsgroup_classstructure_mixins Mix-In Classes for Graphs

  \see \ref jkqtplotter_mixins

  In addition there are mix-in classes that are used via multiple inheritance
  that add additional features and properties to a graph. A prominent example are the classes for \ref jkqtplotter_basegraphserrors "error indicators".
  With these there are usually two variants of one type of graph: One without error indicators and one with error indicators, e.g.:
    - JKQTPXYLineGraph shows lines+symbols graphs made up from x/y-value pairs for each data point.
    - JKQTPXYLineErrorGraph extends JKQTPXYLineGraph with error indicator drawing/properties provided by JKQTPXYGraphErrors
  .
  This approach allows to keep interfaces and appearance recognizeable over different graph classes and locates the source code
  for a feature like error indicators in a single/in few class(es).

  Another example of such a class is JKQTPColorPaletteStyleAndToolsMixin, which provides functions that allow to use color palettes. It is 
  mainly used for the \ref jkqtplotter_imagelots "Image/Matrix graphs", but also by e.g. JKQTPXYParametrizedScatterGraph.


  
  
*/



