[Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/) # JKQtPlotter ## Different Types of Errorindicators This project (see `./test/simpletest_errorbarstyles/`) simply creates a JKQtPlotter widget (as a new window) and adds several curves show-casing different styles of error indicators. Data is initialized from two QVector objects. The source code of the main application can be found in [`jkqtplotter_simpletest_errorbarstyles.cpp´]((https://github.com/jkriege2/JKQtPlotter/blob/master/test/simpletest_errorbarstyles/jkqtplotter_simpletest_errorbarstyles.cpp). First some data is added to the internal datastore (mostly, like explained in several other examples, like e.g. [Line Graph with Different Symbols and Line Styles](https://github.com/jkriege2/JKQtPlotter/tree/master/test/simpletest_symbols_and_styles)). The (in a loop) several graphs are added, each with a distinct style for its error indicators: ```c++ // 3. now we make several plots with different error styles // for that we iterate over every style from the vector errorStyles // the array showXandYError indicates whether we want x- and y-error // for a style for all stywhere this is false, only y-error-indicators // are shown QVector errorStyles {JKQTPnoError, JKQTPerrorBars, JKQTPerrorSimpleBars, JKQTPerrorLines, JKQTPerrorPolygons, JKQTPerrorBoxes, JKQTPerrorEllipses, JKQTPerrorBarsPolygons, JKQTPerrorBarsLines, JKQTPerrorSimpleBarsLines, JKQTPerrorSimpleBarsPolygons }; QVector showXandYError { false , true , true , false , false , true , true , false , false , false , false }; for (int errorID=0; errorID Y; for (auto& xx: X) { Y<(errorID)*2.5; } // create a graph object JKQTPxyLineErrorGraph* graph=new JKQTPxyLineErrorGraph(&plot); // copy data into datastore and immediately set the yColumn graph->set_xColumn(columnX); graph->set_yColumn(ds->addCopiedColumn(Y, "y"+QString::number(errorID))); graph->set_xErrorColumn(columnXError); graph->set_yErrorColumn(columnYError); // set error style, for the y-axis graph->set_yErrorStyle(errorStyles[errorID]); // no error indicators for the x-values graph->set_xErrorStyle(JKQTPnoError); // ... unless: for some error styles we want error in both directions if (showXandYError[errorID]) { graph->set_xErrorStyle(errorStyles[errorID]); graph->set_drawLine(false); } // make error indicator 30% transparent QColor c=graph->get_errorFillColor(); c.setAlphaF(0.3); graph->set_errorFillColor(c); // set error indicator line width graph->set_errorWidth(1); // set length of small bars at the end of error bars graph->set_errorbarSize(15); // set symbol (cross/X) + pen style (and color)dashed) graph->set_symbol(JKQTPcross); graph->set_style(Qt::DashLine); // set symbol size graph->set_symbolSize(5); // set width of symbol lines graph->set_symbolWidth(1); // set width of graph line graph->set_lineWidth(1); // graph title is made from symbol+errorStylestyle, we use the LaTeX instruction \verb around the // result of JKQTPerrorPlotstyle2String(), because it contains underscores that would otherwise // lead to lower-case letter, which we don't want graph->set_title("\\verb{"+JKQTPerrorPlotstyle2String(errorStyles[errorID])+"}"); // add the graph to the plot, so it is actually displayed plot.addGraph(graph); } ``` The error styles are set in these lines: ```c++ // set error style, for the y-axis graph->set_yErrorStyle(errorStyles[errorID]); // no error indicators for the x-values graph->set_xErrorStyle(errorStyles[errorID]); ``` There are several variables that can be used to further style the error indicator, like: ```c++ // make error indicator 30% transparent QColor c=graph->get_errorFillColor(); c.setAlphaF(0.3); graph->set_errorFillColor(c); // set error indicator line width graph->set_errorWidth(1); // set length of small bars at the end of error bars graph->set_errorbarSize(15); ``` There are more properties that you can find in the documentation of the mix-in classes `JKQTPxyGraphErrors`, `JKQTPxGraphErrors`, `JKQTPyGraphErrors`, `JKQTPgraphErrors`. In addition the plot key is moved outside the pot and the grid in the plot is switched off: ```c++ // 6. change locaion of key (outside top-right) plot.get_plotter()->set_keyPosition(JKQTPkeyOutsideRightTop); // ... and switch off the grid plot.getXAxis()->set_drawGrid(false); plot.getXAxis()->set_drawMinorGrid(false); plot.getYAxis()->set_drawGrid(false); plot.getYAxis()->set_drawMinorGrid(false); ``` The result looks like this: ![jkqtplotter_simpletest_errorbarstyles](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles.png) Error bars are implemented in the mixin-classes `JKQTPxyGraphErrors`, `JKQTPxGraphErrors` and `JKQTPyGraphErrors` that are all derived from `JKQTPgraphErrors`. With these it is simple to add error indicators to several different plot styles. Usually you can recognize these by looking at the class name, e.g. `JKQTPxyLineGraph` is a simple line+symbol graph, and `JKQTPxyLineErrorGraph` is the same with error indictaors (see above). There are also several other plots with error indicators: - `JKQTPbarVerticalErrorGraph` for barcharts with errors:
![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles_barcharts.png) - `JKQTPimpulsesVerticalGraph` for impulse/candle-stick charts with errors:
![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles_impulses.png) - `JKQTPfilledCurveXErrorGraph` for filled curves with errors:
![](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_errorbarstyles_filledcurves.png) . [Back to JKQTPlotter main page](https://github.com/jkriege2/JKQtPlotter/)