cpupiemarker.cpp

QWT5.01用于Qt开发的二维图形库程序

#include <qpainter.h>
#include <qwt_scale_map.h>
#include <qwt_plot_curve.h>
#include "cpuplot.h"
#include "cpupiemarker.h"

CpuPieMarker::CpuPieMarker()
{
    setZ(1000);
#if QT_VERSION >= 0x040000
    setRenderHint(QwtPlotItem::RenderAntialiased, true);
#endif
}

int CpuPieMarker::rtti() const
{
    return QwtPlotItem::Rtti_PlotUserItem;
}

void CpuPieMarker::draw(QPainter *p, 
    const QwtScaleMap &, const QwtScaleMap &,
    const QRect &rect) const
{
    const CpuPlot *cpuPlot = (CpuPlot *)plot();

    const QwtScaleMap yMap = cpuPlot->canvasMap(QwtPlot::yLeft);

    const int margin = 5;
    
    QRect pieRect;
    pieRect.setX(rect.x() + margin);
    pieRect.setY(rect.y() + margin);
    pieRect.setHeight(yMap.transform(80.0));
    pieRect.setWidth(pieRect.height());
    
    const int dataType[] = { CpuPlot::User, CpuPlot::System, CpuPlot::Idle };

    int angle = (int)(5760 * 0.75);
    for ( unsigned int i = 0; 
        i < sizeof(dataType) / sizeof(dataType[0]); i++ )
    {
        const QwtPlotCurve *curve = cpuPlot->cpuCurve(dataType[i]);
        if ( curve->dataSize() > 0 )
        {
            const int value = (int)(5760 * curve->y(0) / 100.0);

            p->save();
            p->setBrush(QBrush(curve->pen().color(), Qt::SolidPattern));
            if ( value != 0 )
                p->drawPie(pieRect, -angle, -value);
            p->restore();

            angle += value;
        }
    }
}