JKQtPlotter/examples/simpletest_impulsesplot/README.md
2019-01-12 14:02:12 +01:00

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# JKQtPlotter
## Simple impulse plots
This project (see `./examples/simpletest_impulsesplot/`) simply creates a JKQtPlotter widget (as a new window) and adds a single impulse graph.
The soruce code of the main application is (see [`jkqtplotter_simpletest_impulsesplot.cpp`](../simpletest_impulsesplot/jkqtplotter_simpletest_impulsesplot.cpp).
First data for a curve is calculated and stored in `QVector<double>`:
```c++
QVector<double> X, Y;
for (int i=0; i<Ndata; i++) {
const double xx=double(i)/double(Ndata)*6.0*M_PI;
X << xx;
Y << cos(xx)*exp(-xx/10.0);
}
```
... and finally the data is copied into the datastore
```c++
size_t columnX=ds->addCopiedColumn(X, "x");
size_t columnY=ds->addCopiedColumn(Y, "y");
```
Now an impulse graph object is generated and added to the plot:
```c++
JKQTPimpulsesVerticalGraph* graph=new JKQTPimpulsesVerticalGraph(&plot);
graph->set_xColumn(columnX);
graph->set_yColumn(columnY);
graph->set_lineWidth(2);
graph->set_color(QColor("red"));
graph->set_title(QObject::tr("$\\cos(x)\\cdot\\exp(-x/10)$"));
plot.addGraph(graph);
```
The result looks like this:
![jkqtplotter_simpletest_impulsesplot](../../screenshots/jkqtplotter_simpletest_impulsesplot.png)
There is an alternative class `JKQTPimpulsesHorizontalGraph` which draws horizontal impulse plots:
```c++
JKQTPimpulsesHorizontalGraph* graph=new JKQTPimpulsesHorizontalGraph(&plot);
graph->set_yColumn(columnX);
graph->set_xColumn(columnY);
graph->set_lineWidth(2);
graph->set_color(QColor("blue"));
graph->set_title(QObject::tr("$\\cos(x)\\cdot\\exp(-x/10)$"));
```
This code snippet results in a plot like this:
![jkqtplotter_simpletest_impulsesplot](../../screenshots/jkqtplotter_simpletest_impulsesplot_horizontal.png)
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