基于Qt的虚拟示波器.zip

#include "plot.h" #include "curvedata.h" #include "signaldata.h" #include <qwt_plot_grid.h> #include <qwt_plot_layout.h> #include <qwt_plot_canvas.h> #include <qwt_plot_marker.h> #include <qwt_plot_curve.h> #include <qwt_plot_directpainter.h> #include <qwt_curve_fitter.h> #include <qwt_painter.h> #include <qevent.h> class Canvas: public QwtPlotCanvas //定义Canvas画布类 { public: Canvas( QwtPlot *plot = NULL ): QwtPlotCanvas( plot ) { // The backing store is important, when working with widget // overlays ( f.e rubberbands for zooming ). // Here we don't have them and the internal // backing store of QWidget is good enough. setPaintAttribute( QwtPlotCanvas::BackingStore, false ); setBorderRadius( 10 ); if ( QwtPainter::isX11GraphicsSystem() ) { #if QT_VERSION < 0x050000 // Even if not liked by the Qt development, Qt::WA_PaintOutsidePaintEvent // works on X11. This has a nice effect on the performance. setAttribute( Qt::WA_PaintOutsidePaintEvent, true ); #endif // Disabling the backing store of Qt improves the performance // for the direct painter even more, but the canvas becomes // a native window of the window system, receiving paint events // for resize and expose operations. Those might be expensive // when there are many points and the backing store of // the canvas is disabled. So in this application // we better don't disable both backing stores. if ( testPaintAttribute( QwtPlotCanvas::BackingStore ) ) { setAttribute( Qt::WA_PaintOnScreen, true ); setAttribute( Qt::WA_NoSystemBackground, true ); } } setupPalette(); } private: void setupPalette() { QPalette pal = palette(); #if QT_VERSION >= 0x040400 QLinearGradient gradient; gradient.setCoordinateMode( QGradient::StretchToDeviceMode ); gradient.setColorAt( 0.0, QColor( 0, 49, 110 ) ); gradient.setColorAt( 1.0, QColor( 0, 87, 174 ) ); pal.setBrush( QPalette::Window, QBrush( gradient ) ); #else pal.setBrush( QPalette::Window, QBrush( color ) ); #endif // QPalette::WindowText is used for the curve color // 设置曲线的颜色 pal.setColor( QPalette::WindowText, Qt::yellow ); setPalette( pal ); } }; Plot::Plot( QWidget *parent ): //定义Plot类的构造函数 QwtPlot( parent ), d_paintedPoints( 0 ), //初始化Plot类的部分数据成员 d_interval( 0.0, 10.0 ), d_timerId( -1 ) { d_directPainter = new QwtPlotDirectPainter(); setAutoReplot( false ); setCanvas( new Canvas() ); plotLayout()->setAlignCanvasToScales( true ); setAxisTitle( QwtPlot::xBottom, "Time [s]" ); setAxisScale( QwtPlot::xBottom, d_interval.minValue(), d_interval.maxValue() ); setAxisScale( QwtPlot::yLeft, -200.0, 200.0 ); /* 画网格 */ QwtPlotGrid *grid = new QwtPlotGrid(); grid->setPen( Qt::gray, 0.0, Qt::DotLine ); grid->enableX( true ); grid->enableXMin( true ); grid->enableY( true ); grid->enableYMin( false ); grid->attach( this ); /* 画X-Y轴直线*/ d_origin = new QwtPlotMarker(); d_origin->setLineStyle( QwtPlotMarker::Cross ); //Crosshair十字光标 d_origin->setValue( d_interval.minValue() + d_interval.width() / 2.0, 0.0 ); d_origin->setLinePen( Qt::gray, 0.0, Qt::DashLine ); d_origin->attach( this ); /* 新建绘制曲线PlotCurve类对象 */ d_curve = new QwtPlotCurve(); d_curve->setStyle( QwtPlotCurve::Lines ); d_curve->setPen( canvas()->palette().color( QPalette::WindowText ) ); d_curve->setRenderHint( QwtPlotItem::RenderAntialiased, true ); d_curve->setPaintAttribute( QwtPlotCurve::ClipPolygons, false ); d_curve->setData( new CurveData() ); //实例化一个曲线数据CurveData类对象，并将其设置为绘制曲线对象的数据 d_curve->attach( this ); } Plot::~Plot() { delete d_directPainter; } void Plot::start() { //为定时器提供更高精度的clock d_clock.start(); //启动定时器，设置定时器事件产生的间隔为10mS d_timerId = startTimer( 10 ); } /* 重绘 */ void Plot::replot() { //用法：static_cast < type-id > ( expression ) //该运算符把expression转换为type-id类型，但没有运行时类型检查来保证转换的安全性。 //将QwtSeriesData指针类型显示强制转换为CurveData指针类型 //CurveData类继承自QwtSeriesData类 CurveData *data = static_cast<CurveData *>( d_curve->data() ); data->values().lock(); QwtPlot::replot(); /* d_paintedPoints变量记录了，已经绘制的容器中点的个数 */ d_paintedPoints = data->size(); data->values().unlock(); } /* 设置显示区间的长度，单位：秒，并重绘 */ void Plot::setIntervalLength( double interval ) { if ( interval > 0.0 && interval != d_interval.width() ) { //设置区间的最大值 d_interval.setMaxValue( d_interval.minValue() + interval ); //设置X轴的比例 setAxisScale( QwtPlot::xBottom, d_interval.minValue(), d_interval.maxValue() ); //重绘 replot(); } } /* 更新曲线，在定时器事件中周期性调用 */ void Plot::updateCurve() { CurveData *data = static_cast<CurveData *>( d_curve->data() ); data->values().lock(); const int numPoints = data->size(); if ( numPoints > d_paintedPoints ) { /* WA_PaintOnScreen属性，指示窗口部件想要直接画在屏幕上 */ const bool doClip = !canvas()->testAttribute( Qt::WA_PaintOnScreen ); if ( doClip ) //如果窗口部件不是要直接画在屏幕上 { /* Depending on the platform setting a clip might be an important performance issue. F.e. for Qt Embedded this reduces the part of the backing store that has to be copied out - maybe to an unaccelerated frame buffer device. */ const QwtScaleMap xMap = canvasMap( d_curve->xAxis() ); const QwtScaleMap yMap = canvasMap( d_curve->yAxis() ); QRectF br = qwtBoundingRect( *data, d_paintedPoints - 1, numPoints - 1 ); const QRect clipRect = QwtScaleMap::transform( xMap, yMap, br ).toRect(); /* 设置增量式画家的剪切区域 */ d_directPainter->setClipRegion( clipRect ); } /* 使用增量式画家，绘制一系列点 */ /* * 由此可以看出，如果没有缩放绘图比例，紧紧增加了一系列点，则不会调用replot函数，而是 * 调用增量式绘图函数，这样可以更高效 */ d_directPainter->drawSeries( d_curve, d_paintedPoints - 1, numPoints - 1 ); /* * 变量d_paintedPoints记录了，上次容器中的元素数量， * 再次绘制时，从上次的最后一个元素+1的地方开始增量式绘制 */ d_paintedPoints = numPoints; } data->values().unlock(); } /* 增加区间，并重绘：当一屏数据显示完成，需要重头显示的时候调用 */ void Plot::incrementInterval() { /* 设置区间 */ d_interval = QwtInterval( d_interval.maxValue(), d_interval.maxValue() + d_interval.width() ); CurveData *data = static_cast<CurveData *>( d_curve->data() ); /* 清除x轴坐标小于区间最小值的点，这种做法，可能会清除一部分还没有绘制的点 */ data->values().clearStaleValues( d_interval.minValue() ); // To avoid, that the grid is jumping, we disable // the autocalculation of the ticks and shift them // manually instead. /* 设置x�