2.9 KiB
Example (JKQTPlotter): Step Line Plots in Different Styles
This project (see ./examples/simpletest_stepplots/) simply creates a JKQTPlotter widget (as a new window) and adds a single line-graph (a sine-wave). Data is initialized from two QVector objects.
The source code of the main application can be found in jkqtplotter_simpletest_stepplots.cpp. For the most part, several datasets of cosine-curves are generated. then thrre tuples of graphs are added: One of type JKQTPXYLineGraph, which simply indicates the location of the actual datapoints. the second is of type JKQTPStepHorizontalGraph, which adds the step-graph to the plot:
// 3 now we make several plots with different step styles, each one also contains a
// symbol plot indicating the location of the datapoints themselves
JKQTPStepHorizontalGraph* graph;
JKQTPXYLineGraph* graphL;
//-- JKQTPStepLeft ----------------------------------------------------------------------------------------
graph=new JKQTPStepHorizontalGraph(&plot);
graphL=new JKQTPXYLineGraph(&plot);
// set data for both graphs
graph->setXColumn(columnX); graphL->setXColumn(graph->getXColumn());
graph->setYColumn(columnY1); graphL->setYColumn(graph->getYColumn());
// set step style
graph->setStepType(JKQTPStepLeft);
graph->setLineWidth(1);
graph->setFillCurve(true);
graph->setDrawLine(true);
graph->setTitle("JKQTPStepLeft, filled");
Note that you can configure the step type (left/center/right by graph->setStepType(JKQTPStepLeft). With graph->setFillCurve(true) you can draw the curve filled until the y=0-axis and with graph->setDrawLine(true) you can switch the line along the values on and off (e.g. to only have the filled area, but no line).
Finally the JKQTPXYLineGraph is configured:
// set symbol + pen style and color for the added circles, copy color
graphL->setSymbol(JKQTPGraphSymbols::JKQTPCircle);
graphL->setDrawLine(false);
graphL->setSymbolSize(9);
graphL->setSymbolWidth(1);
graphL->setColor(graph->getColor());
... and all graphs are added to the plot:
// add the graphs to the plot, so it is actually displayed
plot.addGraph(graph);
plot.addGraph(graphL);
In addition to the symbol type and line style, you can also alter the size of the symbols (graph->setSymbolSize(14)), the line-width used to draw them (graph->setSymbolWidth(1.5)) and the line width of the graph line (graph->setLineWidth(1)). If you want to switch off the line altogether, use graph->setDrawLine(false.
The result looks like this:
