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114 lines
5.5 KiB
Markdown
114 lines
5.5 KiB
Markdown
# Example (JKQTPlotter): Scatter-graph with custom symbols {#JKQTPlotterscatterCustomSymbol}
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This project (see `./examples/scatter_customsymbol/`) demonstrates using JKQTPlotter to draw a scatter graph (JKQTPXYScatterGraph) with custom symbols.
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The source code of the example can be found in [`jkqtplotter_scatter.cpp`](https://github.com/jkriege2/JKQtPlotter/tree/master/examples/scatter_customsymbol/scatter_customsymbol.cpp).
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First we create a plotter window and get a pointer to the internal datastore (for convenience):
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```.cpp
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JKQTPlotter plot;
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JKQTPDatastore* ds=plot.getDatastore();
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```
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Now we add several columns to the JKQTPDatastore and obtain back-inserter iterators for these:
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```.cpp
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size_t columnX=ds->addColumn("x");
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auto colXInserter=ds->backInserter(columnX);
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size_t columnY1=ds->addColumn("y1");
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auto colY1Inserter=ds->backInserter(columnY1);
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size_t columnY2=ds->addColumn("y2");
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auto colY2Inserter=ds->backInserter(columnY2);
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size_t columnY3=ds->addColumn("y3");
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auto colY3Inserter=ds->backInserter(columnY3);
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size_t columnY4=ds->addColumn("y4");
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auto colY4Inserter=ds->backInserter(columnY4);
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```
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... and fill the columns with data
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```.cpp
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const int Ndata=5;
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for (int i=0; i<Ndata; i++) {
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// put data
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const double x=double(i)/double(Ndata-1);
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*(colXInserter++)=x;
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*(colY1Inserter++)=3.0+pow(x*1.3, 2.0)*1.3;
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*(colY2Inserter++)=2.0+pow(x*1.3, 2.0)*1.2;
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*(colY3Inserter++)=1.0+pow(x*1.3, 2.0)*1.1;
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*(colY4Inserter++)=pow(x*1.3, 2.0);
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}
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```
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Now we create several graph objects of type JKQTPXYScatterGraph. Each one uses a different custom symbol style:
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Graphs `graph3` and `graph4` use `JKQTPCharacterSymbol` and `JKQTPFilledCharacterSymbol` respectively to draw spades and hearts from the unicode characters `U+2660` and `U+2665` respectively. The two graphs differ in the coloring of the symbols. The `JKQTPCharacterSymbol` variant would use the color default (cycling) graph color, but here we overwrite this with `darkblue`. The `JKQTPFilledCharacterSymbol` variant uses red filled hearts with a thin black border.
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```.cpp
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JKQTPXYScatterGraph* graph3=new JKQTPXYScatterGraph(&plot);
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graph3->setXColumn(columnX);
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graph3->setYColumn(columnY3);
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graph3->setSymbolType(JKQTPCharacterSymbol+QChar(0x2660).unicode());
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graph3->setSymbolColor(QColor("darkblue"));
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graph3->setSymbolSize(15);
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graph3->setTitle(QObject::tr("spades"));
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plot.addGraph(graph3);
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JKQTPXYScatterGraph* graph4=new JKQTPXYScatterGraph(&plot);
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graph4->setXColumn(columnX);
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graph4->setYColumn(columnY4);
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graph4->setSymbolType(JKQTPFilledCharacterSymbol+QChar(0x2665).unicode());
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graph4->setSymbolSize(20);
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graph4->setSymbolColor(QColor("black"));
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graph4->setSymbolFillColor(QColor("red"));
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graph4->setSymbolLineWidth(0.5);
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graph4->setTitle(QObject::tr("hearts"));
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plot.addGraph(graph4);
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```
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The more advanced graphs `graph1` and `graph2` use `JKQTPRegisterCustomGraphSymbol()` to register functors that draw user-specific symbols:
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```.cpp
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JKQTPCustomGraphSymbolFunctor f=[](QPainter& p) {
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p.setBrush(Qt::NoBrush); // ensure that circles are not drawn filled
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p.drawEllipse(QPointF(-0.33, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.drawEllipse(QPointF(0, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.drawEllipse(QPointF(0.33, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.drawEllipse(QPointF(-0.33/2.0, 0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.drawEllipse(QPointF(0.33/2.0, 0.33/4.0), 0.33/2.0, 0.33/2.0);
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};
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JKQTPGraphSymbols customsymbol_olympicrings=JKQTPRegisterCustomGraphSymbol(f);
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JKQTPXYScatterGraph* graph1=new JKQTPXYScatterGraph(&plot);
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graph1->setXColumn(columnX);
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graph1->setYColumn(columnY1);
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graph1->setSymbolType(customsymbol_olympicrings);
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graph1->setSymbolSize(30);
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graph1->setTitle(QObject::tr("olympics"));
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plot.addGraph(graph1);
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JKQTPGraphSymbols customsymbol_coloredolympicrings=JKQTPRegisterCustomGraphSymbol(
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[](QPainter& p) {
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p.setBrush(Qt::NoBrush); // ensure that circles are not drawn filled
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const double w=p.pen().widthF();
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p.setPen(QPen(QColor("red"), w));
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p.drawEllipse(QPointF(-0.33, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.setPen(QPen(QColor("black"), w));
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p.drawEllipse(QPointF(0, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.setPen(QPen(QColor("gold"), w));
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p.drawEllipse(QPointF(0.33, -0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.setPen(QPen(QColor("darkgreen"), w));
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p.drawEllipse(QPointF(-0.33/2.0, 0.33/4.0), 0.33/2.0, 0.33/2.0);
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p.setPen(QPen(QColor("darkblue"), w));
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p.drawEllipse(QPointF(0.33/2.0, 0.33/4.0), 0.33/2.0, 0.33/2.0);
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});
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JKQTPXYScatterGraph* graph2=new JKQTPXYScatterGraph(&plot);
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graph2->setXColumn(columnX);
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graph2->setYColumn(columnY2);
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graph2->setSymbolType(customsymbol_coloredolympicrings);
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graph2->setSymbolSize(30);
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graph2->setTitle(QObject::tr("colored olympics"));
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plot.addGraph(graph2);
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```
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Bothe variant show the olympic rings. `graph1` uses the (cycling) default graph color and `graph2` draws with user-defined colors.
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The result looks like this:
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