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.
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 )
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:
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
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).
\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:
Several pre-made styles are available in the JKQTPlotter repository (<a href="https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotterressources/styles/">https://github.com/jkriege2/JKQtPlotter/tree/master/lib/jkqtplotterressources/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:
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 ...)
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 ).
