JKQtPlotter/doc/dox/jkqtplotter.dox

/*!

\defgroup jkqtptools Support Function library (e.g. for JKQTPlotter)

This group contains several tool functions and datatypesthat are neccessary for 
JKQTPlotter, JKQTMathtext and the other major classes in this library, but may 
also be used separately. The functions and datatypes are sorted into several
functionaly groups.


\defgroup jkqtptools_algorithms Diverse Algorithms
\ingroup jkqtptools

\defgroup jkqtptools_math Mathematical Computations & Expression Parsing
\ingroup jkqtptools

\defgroup jkqtptools_math_basic Mathematical Functions & Tools
\ingroup jkqtptools_math


This group assembles a variety of mathematical tool functions that are used in different places.

\defgroup jkqtptools_math_array Data Array Tools
\ingroup jkqtptools_math

Functions in this group form the basis for the statistics  (\ref jkqtptools_math_statistics ) and linear algebra libraries  (\ref jkqtptools_math_linalg ), by providing allocation and freeing of (aligned) memory arrays.

\see JKQTPlotterBasicJKQTPDatastoreStatistics

\defgroup jkqtptools_math_linalg Linear Algebra Tools
\ingroup jkqtptools_math

This group assembles a basic set of linear algebra methods, including matrix inversion, which are required e.g. by the statistics library (\ref jkqtptools_math_statistics )

\defgroup jkqtptools_math_statistics Statistical Computations
\ingroup jkqtptools_math

This group contains a statistics library, which offers several basic methods and is based on an iterator interface:
  - \ref jkqtptools_math_statistics_basic
  - \ref jkqtptools_math_statistics_grouped
  - \ref jkqtptools_math_statistics_regression
  - \ref jkqtptools_math_statistics_poly
  - \ref jkqtptools_math_statistics_1dhist
  - \ref jkqtptools_math_statistics_2dhist
  - \ref jkqtptools_math_statistics_1dkde
  - \ref jkqtptools_math_statistics_2dkde
.
In addition there is a set of "adaptors" (see \ref jkqtptools_math_statistics_adaptors ) that shortcut the calculation of a statistical property and the subsequent parametrization of a plot with the results. With these adaptors you can add e.g. a boxplot or histogram chart to a plot by calling only one function.


All statistics functions use an iterator-based interface, comparable to the interface of the <a href="http://www.cplusplus.com/reference/algorithm/">algorithms in the C++ standard template library</a>. To this end, the class `JKQTPDatastore` provides an iterator interface to its columns, using the functions `JKQTPDatastore::begin()` and `JKQTPDatastore::end()`. Both functions simply receive the column ID as parameter and exist in a const and a mutable variant. the latter allows to also edit the data. In addition the function `JKQTPDatastore::backInserter()` returns a back-inserter iterator (like generated for STL containers with `std::back_inserter(container)`) that also allows to append to the column.

Note that the iterator interface allows to use these functions with any container that provides such iterators (e.g. `std::vector<double>`, `std::list<int>`, `std::set<float>`, `QVector<double>`...).

Code using one of these statistics functions therefore may look e.g. like this:
\code
    // mean of a column in a JKQTPDatastore:
    double mean=jkqtpstatAverage(datastore1->begin(randomdatacol1), datastore1->end(randomdatacol1));
    
    // mean of a std::vector
    std::vector<double> data {1,2,4,5,7,8,10,2,1,3,5};
    double meanvec=jkqtpstatAverage(data.begin(), data.end());
\endcode

All statistics functions use all values in the given range and convert each value to a `double`, using `jkqtp_todouble()`. The return values is always a dohble. Therefore you can use these functions to calculate statistics of ranges of any type that can be converted to `double`. Values that do not result in a valid `double`are not used in calculating the statistics. Therefore you can exclude values by setting them `JKQTP_DOUBLE_NAN` (i.e. "not a number").

\see see for detailed examples: \ref JKQTPlotterBasicJKQTPDatastoreStatistics 

\defgroup jkqtptools_math_statistics_basic Basic statistics
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_grouped Grouped statistics
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_regression Regression Analysis
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_poly Polynomial Fits/Regression
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_1dhist 1-dimensional Histograms 
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_2dhist 2-dimensional Histograms
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_1dkde 1-dimensional Kernel Density Estimates
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_1dkde_kernels Kernels for 1-dimensional Histograms
\ingroup jkqtptools_math_statistics_1dkde

\defgroup jkqtptools_math_statistics_2dkde 2-dimensional Kernel Density Estimates 
\ingroup jkqtptools_math_statistics

\defgroup jkqtptools_math_statistics_2dkde_kernels Kernels for 2-dimensional Histograms
\ingroup jkqtptools_math_statistics_2dkde

\defgroup jkqtptools_math_statistics_adaptors Statistics To Plot Adaptors
\ingroup jkqtptools_math_statistics



\defgroup jkqtptools_string String/String-Conversion Tool Functions
\ingroup jkqtptools

Offers diverse function to convert different datatypes (e.g. double, int, diverse enums) to and from strings and for string manipulation.

\defgroup jkqtptools_qt Additional Tools for Qt
\ingroup jkqtptools


\defgroup jkqtptools_qtwidgets Additional Widgets for Qt
\ingroup jkqtptools

\defgroup jkqtptools_drawing Drawing & Graphics Tools
\ingroup jkqtptools

Specialized drawing functions used by the plotters and LaTeX renderers.

\defgroup jkqtptools_debugging Debugging Tools
\ingroup jkqtptools

Functions that help during debugging (e.g. an assert function/macro).

\defgroup jkqtptools_codestructuring Code Structuring Tools
\ingroup jkqtptools

Classes and functions that help to structure the code (e.g. RAII constructs)

\defgroup jkqtptools_enums Enums for JKQTPlotter (including String Conversion)
\ingroup jkqtptools

Assembles diverse ENUMs required by JKQTPlotter.



\defgroup jkqtplotter JKQTPlotter: Qt based Scientific Plotter Class

A Qt based plotter for 2D scientific graphs. Main Plotting widget is JKQTPlotter.


\defgroup jkqtpdatastorage Data Storage Classes/System
\ingroup jkqtplotter

The classes in this group implement a data storage system for use with the main plotter class.
Basically a table of data is generated as a set of logical columns that may be bound to different
data sources (internal or external memory arrays. Later on it is simply possible to plot graphs
using the column number and the not a link to the actual data array, as the link is stored in these
classes.

\see \ref JKQTPlotterBasicJKQTPDatastore for a detailed description of how to use this class for data management!

\defgroup jkqtpexternalinterfaces Interfaces To Other Libraries
\ingroup jkqtpdatastorage


\defgroup jkqtpinterfaceopencv OpenCV Interfaceing Tools
\ingroup jkqtpexternalinterfaces

Classes and functions in this group allow JKQTPlotter to directly work with <a href="https://opencv.org/">OpenCV</a> data structures.

Examples:
  - \ref JKQTPlotterImagePlotOpenCV  
  - \ref JKQTPlotterImagePlotRGBOpenCV 
.

The OpenCV-binding itself is header-only, and NOT compiled into the JKQtPlotter libraries. Therefore you can simply include the header and use the facilities provided by it.

The CMake-build system of JKQtPlotter (and its examples) is compatible with both OpenCV 3.4.x and 4.x and uses the standard `find_package(OpenCV)` facilities provided by OpenCV to compile and bind against that library. 
If you want to build the OpenCV-based JKQtPlotter examples (see list above), you either have to ensure that CMake finds OpenCV by itself (i.e. somewhere in the default search paths), or you can set the CMake variable `OpenCV_DIR` so it points to the OpenCV directory before configuring JKQtPlotter.



\defgroup jkqtpinterfacecimg CImg Interfaceing Tools
\ingroup jkqtpexternalinterfaces

Classes and functions in this group allow JKQTPlotter to directly work with <a href="http://cimg.eu/">CImg</a> data structures <a href="http://cimg.eu/reference/structcimg__library_1_1CImg.html">CImg&lt;T&gt></a>.

Examples:
  - \ref JKQTPlotterImagePlotCImg
  - \ref JKQTPlotterImagePlotRGBCImg
.

The CImg-binding itself is header-only (as CImg is itself), and NOT compiled into the JKQtPlotter libraries. Therefore you can simply include the header and use the facilities provided by it.

The CMake-build system of JKQtPlotter (and its examples) provides facilities to allow for `find_package(CImg)` to compile against that library. 
If you want to build the CImg-based JKQtPlotter examples (see list above), you either have to ensure that CMake finds CImg by itself (i.e. somewhere in the default search paths, e.g. `CMAKE_INSTALL_PREFIX`), or you can set the CMake variable `CImg_DIR` so it points to the directory of the `CImg.h` file, or  before configuring JKQtPlotter.



\defgroup jkqtpplottersupprt Support Classes and Functions
\ingroup jkqtplotter

\defgroup jkqtpplotterclasses Plotter Class & Plotter Widget
\ingroup jkqtplotter

This group contains the actual plotter classes, that implement layout management code,
coordinate system management an actual plotter widget ... 

There are two main classes:
  - JKQTBasePlotter is a QObject-derived class that implements all the plotting logic and drawing code. It does not implement a Qt widget though.
  - JKQTPlotter is a QWidget-based class that contains a JKQTBasePlotter and uses it to draw plots onto a Qt form.
.


\defgroup jkqtplotter_elements Plot Elements
\ingroup jkqtplotter

This group assembles all classes that represent different elements of a plot (managed by JKQTBasePlotter/JKQTPlotter).
There are these major subgroups:
  - \ref jkqtpbaseplotter_elements contains all non-graph objects, i.e. things like coordinate axes and so on
  - \ref jkqtplotter_graphsgroup contains the actual graph classes
  - \ref jkqtplotter_overlays contains classes for overlay elements (lines, marker ...) that can be drawn quickly on top of a plot
.

\defgroup jkqtpbaseplotter_elements Basic (non-graph) Plot Elements (coordinate axes, ...)
\ingroup jkqtplotter_elements

This group contains some tool classes that implement basic elements of the plot (coordinate axes, key, ...).
These classes are used by JKQTPlotterBase to output the plot.


\defgroup jkqtplotter_graphsgroup Graph Classes
\ingroup jkqtplotter_elements

This group contains all classes in the JKQTPlotter library that may be used to draw a graph (i.e. a curve) onto a plot.

\tableofcontents

\section jkqtplotter_graphsgroup_classstructure Graph Class Structure

\subsection jkqtplotter_graphsgroup_classstructure_basics Graph Classes

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.

\dotfile jkqtplotter_graphhirarchy.dot

\subsection jkqtplotter_graphsgroup_classstructure_mixins Mix-In Classes for Graphs

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.



\defgroup jkqtplotter_basegraphs Baseclasses for Graphs
\ingroup jkqtplotter_graphsgroup

\defgroup jkqtplotter_basegraphserrors Mix-In Classes for Error Indicators
\ingroup jkqtplotter_basegraphs

\defgroup jkqtplotter_basegraphs_stylemixins Mix-In Classes for Plot Styling
\ingroup jkqtplotter_basegraphs

\defgroup jkqtplotter_linesymbolgraphs Line/Symbol Graphs
\ingroup jkqtplotter_graphsgroup

This group assembles graphs that show their data with symbols and optionally with connecting lines in diferent styles:
<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html beeswarmplot_small.png
      <td> JKQTPSingleColumnSymbolsGraph
    <tr>
      <td>\image html symbols_and_styles_small.png
      <td> JKQTPXYLineGraph, JKQTPXYLineErrorGraph
    <tr>
      <td>\image html paramscatterplot_small.png
      <td> JKQTPXYParametrizedScatterGraph, JKQTPXYParametrizedErrorScatterGraph
    <tr>
      <td>\image html stepplots_small.png
      <td> JKQTPSpecialLineHorizontalGraph, JKQTPSpecialLineVerticalGraph
</table>

\defgroup jkqtplotter_linesymbolgraphs_simple Basic Line/Scatter Graphs
\ingroup jkqtplotter_linesymbolgraphs

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html beeswarmplot_small.png
      <td> JKQTPSingleColumnSymbolsGraph
    <tr>
      <td>\image html symbols_and_styles_small.png
      <td> JKQTPXYLineGraph, JKQTPXYLineErrorGraph
    <tr>
      <td>\image html stepplots_small.png
      <td> JKQTPSpecialLineHorizontalGraph, JKQTPSpecialLineVerticalGraph
</table>


\defgroup jkqtplotter_linesymbolgraphs_param Parametrized Line/Scatter Graphs
\ingroup jkqtplotter_linesymbolgraphs

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html paramscatterplot_small.png
      <td> JKQTPXYParametrizedScatterGraph, JKQTPXYParametrizedErrorScatterGraph
</table>

\defgroup jkqtplotter_filledgraphs Filled Polygon/Area Graphs
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html filledgraphs_small.png
      <td> JKQTPFilledCurveXGraph, JKQTPFilledCurveYGraph
    <tr>
      <td>\image html plot_filledcurvexerrorplots_small.png
      <td> JKQTPFilledCurveXErrorGraph, JKQTPFilledCurveYErrorGraph
    <tr>
      <td>\image html JKQTPfilledVerticalRangeGraph_WithLines_small.png
      <td> JKQTPFilledVerticalRangeGraph
</table>

\defgroup jkqtplotter_functiongraphs Function Graphs
\ingroup jkqtplotter_linesymbolgraphs

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html functionplot_small.png
      <td> JKQTPXParsedFunctionLineGraph,  JKQTPYParsedFunctionLineGraph
</table>

\defgroup jkqtplotter_parsedFgraphs Parsed Function Graphs
\ingroup jkqtplotter_linesymbolgraphs

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html functionplot_small.png
      <td> JKQTPXFunctionLineGraph,  JKQTPYFunctionLineGraph
</table>

\defgroup jkqtplotter_barssticks Barcharts, Impulse-Charts, ...
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html barchart_small.png
      <td> JKQTPBarVerticalGraph,  JKQTPBarHorizontalGraph
    <tr>
      <td>\image html barchart_error_small.png
      <td> JKQTPBarVerticalErrorGraph, JKQTPBarHorizontalErrorGraph
    <tr>
      <td>\image html JKQTPbarVerticalGraphStacked_small.png
      <td> JKQTPBarVerticalStackableGraph, JKQTPBarHorizontalStackableGraph
    <tr>
      <td>\image html impulsesplot_small.png
      <td> JKQTPImpulsesHorizontalGraph, JKQTPImpulsesVerticalGraph
    <tr>
      <td>\image html impulses_errors_small.png
      <td> JKQTPImpulsesHorizontalErrorGraph, JKQTPImpulsesVerticalErrorGraph
</table>

\defgroup jkqtplotter_statgraphs Statistical Graphs (e.g. Boxplots ...)
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html boxplot_small.png
      <td> JKQTPBoxplotVerticalGraph, JKQTPBoxplotHorizontalGraph
    <tr>
      <td>\image html JKQTPViolinplotVerticalElement_small.png
      <td> JKQTPViolinplotVerticalElement, JKQTPViolinplotHorizontalElement
</table>

\see \ref jkqtptools_math_statistics_adaptors for shortcuts to calculate statistical properties of data and then adding a plot with the results.

\defgroup jkqtplotter_geoplots Geometric Elements (Lines, Rectangles, ...)
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html symbol_filled_diamond.png
      <td> JKQTPGeoSymbol
    <tr>
      <td>\image html geo_text_small.png
      <td> JKQTPGeoText
    <tr>
      <td>\image html geo_line_small.png
      <td> JKQTPGeoLine, JKQTPGeoInfiniteLine, JKQTPGeoPolyLines
    <tr>
      <td>\image html geo_rect_small.png
      <td> JKQTPGeoRectangle
    <tr>
      <td>\image html geo_polygon_small.png
      <td> JKQTPGeoPolygon
    <tr>
      <td>\image html geo_ellipse_small.png
      <td> JKQTPGeoEllipse
    <tr>
      <td>\image html geo_arc_small.png
      <td> JKQTPGeoArc
    <tr>
      <td>\image html geo_pie_small.png
      <td> JKQTPGeoPie
    <tr>
      <td>\image html geo_chords_small.png
      <td> JKQTPGeoChord
    <tr>
      <td>\image html geo_boxplot_small.png
      <td> JKQTPBoxplotVerticalElement, JKQTPBoxplotHorizontalElement
    <tr>
      <td>\image html JKQTPViolinplotVerticalElement_small.png
      <td> JKQTPViolinplotVerticalElement, JKQTPViolinplotHorizontalElement
</table>

Examples:
  - \ref JKQTPlotterGeometricGraphs
.

\defgroup jkqtplotter_diverse Diverse Other Graphs (Ranges, ...)
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html JKQTPHorizontalRange_small.png
      <td> JKQTPHorizontalRange, JKQTPVerticalRange
    <tr>
      <td>\image html JKQTPPeakStreamGraphY_small.png
      <td> JKQTPPeakStreamGraph
</table>

\defgroup jkqtplotter_imagelots Matrix/Image Plotting
\ingroup jkqtplotter_graphsgroup

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html rgbimageplot_qt_small.png
      <td> JKQTPImage
    <tr>
      <td>\image html JKQTPMathImageBaseModifyNone_small.png
      <td> JKQTPMathImage, JKQTPColumnMathImage
    <tr>
      <td>\image html rgbimageplots_small.png
      <td> JKQTPRGBMathImage, JKQTPColumnRGBMathImage
    <tr>
      <td>\image html overlayimage_small.png
      <td> JKQTPOverlayImage
    <tr>
      <td>\image html overlayimageenhanced_small.png
      <td>  JKQTPOverlayImageEnhanced, JKQTPColumnOverlayImageEnhanced
    <tr>
      <td>\image html JKQTPContour_small.png
      <td> JKQTPContourPlot, JKQTPColumnContourPlot
</table>

\defgroup jkqtplotter_imagelots_elements Image Graphs
\ingroup jkqtplotter_imagelots


<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html rgbimageplot_qt_small.png
      <td> JKQTPImage
    <tr>
      <td>\image html JKQTPMathImageBaseModifyNone_small.png
      <td> JKQTPMathImage, JKQTPColumnMathImage
    <tr>
      <td>\image html rgbimageplot_cimg_small.png
      <td> JKQTPRGBMathImage, JKQTPColumnRGBMathImage
</table>

\defgroup jkqtplotter_imagelots_overlays Image/Matrix Overlay Graphs
\ingroup jkqtplotter_imagelots

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html overlayimage_small.png
      <td> JKQTPOverlayImage
    <tr>
      <td>\image html overlayimageenhanced_small.png
      <td>  JKQTPOverlayImageEnhanced, JKQTPColumnOverlayImageEnhanced
</table>

\defgroup jkqtplotter_imagelots_tools Tool Functions & Classes for Image Drawing
\ingroup jkqtplotter_imagelots

\defgroup jkqtplotter_imagelots_tools_LUTS Tool Functions to Build Lookup-Tables for Palettes
\ingroup jkqtplotter_imagelots_tools

\defgroup jkqtplotter_imagelots_contour Contour Graphs (based on Image Data)
\ingroup jkqtplotter_imagelots

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>\image html JKQTPContour_small.png
      <td> JKQTPContourPlot, JKQTPColumnContourPlot
</table>

\defgroup jkqtplotter_overlays Overlay Elements
\ingroup jkqtplotter_elements

<table>
    <tr>
      <th> Screenshot
      <th> Classes
    <tr>
      <td>
      <td> JKQTPOverlayVerticalLine, JKQTPOverlayLine
    <tr>
      <td>
      <td> JKQTPOverlayVerticalRange
    <tr>
      <td>
      <td> JKQTPOverlayRectangle
</table>



\defgroup jkqtpplotter_styling JKQTPlotter Styling System
\ingroup jkqtplotter

\image html stylesbanner.png

JKQTPlotter (and JKQTBasePlotter) offer a styling system, which allows to easily define and transfer plot styling from one object to another.
The system is based on a hirarchy of structs, which summarize properties, describing how a plot looks in general. The classes contained in this system are:
  - JKQTPlotterStyle for JKQTPlotter: Defines e.g. basic user-interactions, the display options of the toolbar
  - JKQTBasePlotterStyle for JKQTBasePlotter defines the appearance of the plot itself (colors, axis properties, key properties, default graph colors/styles, ...), contains JKQTPCoordinateAxisStyle instances to configrue the plot's coordinate axes
  - JKQTPCoordinateAxisStyle for JKQTPCoordinateAxis defines the appearance of a coordinate axis (colors, axis properties, ...)
  - JKQTPKeyStyle for the style of the key/legend in a JKQTBasePlotterStyle
.

In addition there are static methods that allow to manage a system-wide (actually program-instance wide) style that is applied to any new instance of JKQTPlotter and JKQTBasePlotter on construction:
  - JKQTPGetSystemDefaultStyle() / JKQTPSetSystemDefaultStyle() allows to access the central instace of JKQTPlotterStyle (mainly properties/style of the GUI-parts and user-action bindings)
  - JKQTPGetSystemDefaultBaseStyle() / JKQTPSetSystemDefaultBaseStyle() accesses the central instance of JKQTBasePlotterStyle (styles the actual plot/graphs with colors, axes styles, ...)
.

You can e.g. use these general methods to alter the styles for all JKQTPlotter instances, created in the future:
\code{.cpp}
    // load the system-wide default settings from an INI-file:
    QSettings plotSettings("JKQTPlotterSettings.ini", QSettings::IniFormat);;
    JKQTPGetSystemDefaultStyle().loadSettings(plotSettings);
    JKQTPGetSystemDefaultBaseStyle().loadSettings(plotSettings);

    // alter a system-wide default setting by hand (here: set color of zooming rect to red)
    JKQTPGetSystemDefaultStyle().userActionColor=QColor("red");
\endcode

Several pre-made styles are available in the JKQTPlotter repository (<a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/">https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/</a>). 
These are also linked into the JKQTPlotter library as Qt ressource into the subdirectory \c :/JKQTPlotter/styles/ . You can use them as follows:

\code{.cpp}
	QSettings plotSettings(":/JKQTPlotter/styles/blackandwhite.ini", QSettings::IniFormat);;
    JKQTPGetSystemDefaultStyle().loadSettings(plotSettings);
    JKQTPGetSystemDefaultBaseStyle().loadSettings(plotSettings);
\endcode

Here is a table with all available ready-made styles:
<table>
    <tr>
      <th> Style-file
      <th> Screenshot
    <tr>
      <td> <b> The Default Style </b>
      <td> \image html style_default.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/simple_gridandticks.ini"> \c :/JKQTPlotter/styles/simple_gridandticks.ini</a>
      <td> \image html style_simple_axesoffset_plotbox.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/simple_axesoffset.ini"> \c :/JKQTPlotter/styles/simple_axesoffset.ini</a>
      <td> \image html style_simple_axesoffset.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/simple_axesoffset_plotbox.ini"> \c :/JKQTPlotter/styles/simple_axesoffset_plotbox.ini</a>
      <td> \image html style_simple_axesoffset_plotbox.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/dark.ini"> \c :/JKQTPlotter/styles/dark.ini</a>
      <td> \image html style_dark.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/blueprint.ini"> \c :/JKQTPlotter/styles/blueprint.ini</a>
      <td> \image html style_blueprint.png
    <tr>
      <td> <a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotter/resources/styles/blackandwhite.ini"> \c :/JKQTPlotter/styles/blackandwhite.ini</a>
      <td> \image html style_blackandwhite.png
</table>

\see For a detailed example, see \ref JKQTPlotterStyling



\defgroup jkqtpqtwidgetsttools Qt Widgets/Tools to work with JKQTPlotter
\ingroup jkqtplotter

This group assembles several Qt widgets and tool classes that are linked to JKQTPlotter/JKQTBasePlotter and allow to build advanced GUIs for these (e.g. model/view access to internal data ...)

\defgroup jkqtpgraphsmodel Qt Data Models to Access Graphs in a JKQTBasePlotter/JKQTPlotter
\ingroup jkqtpqtwidgetsttools

Data models in this group allow to access different internal data from a JKQTBasePlotter/JKQTPlotter and in part to manipulate these.

\defgroup jkqtpcomboboxes Comboboxes for Properties of JKQTBasePlotter/JKQTPlotter
\ingroup jkqtpqtwidgetsttools

This group contains several QComboBox-derived classes that can be used to select different enum-values (e.g. with JKQTPMathImageColorPaletteComboBox you can select a color-palette from JKQTPMathImageColorPalette ).



*/