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 JKQTPColorPaletteTools, 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.
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 ).
