examples/event_filter/plot.cpp

#include "plot.h"
#include "colorbar.h"
#include <qevent.h>
#if QT_VERSION < 0x040000
#include <qwhatsthis.h>
#endif
#include <qwt_plot_layout.h>
#include <qwt_plot_canvas.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_curve.h>
#include <qwt_symbol.h>
#include <qwt_scale_widget.h>
#include <qwt_wheel.h>
#include <stdlib.h>

Plot::Plot(QWidget *parent):
    QwtPlot(parent)
{
    setTitle("Interactive Plot");

    setCanvasColor(Qt::darkCyan);

    QwtPlotGrid *grid = new QwtPlotGrid;
    grid->setMajPen(QPen(Qt::white, 0, Qt::DotLine));
    grid->attach(this);

    // axes

    setAxisScale(QwtPlot::xBottom, 0.0, 100.0);
    setAxisScale(QwtPlot::yLeft, 0.0, 100.0);

    // Avoid jumping when label with 3 digits
    // appear/disappear when scrolling vertically

    QwtScaleDraw *sd = axisScaleDraw(QwtPlot::yLeft);
    sd->setMinimumExtent( sd->extent(QPen(),
        axisWidget(QwtPlot::yLeft)->font()));

    plotLayout()->setAlignCanvasToScales(true);

    insertCurve(Qt::Vertical, Qt::blue, 30.0);
    insertCurve(Qt::Vertical, Qt::magenta, 70.0);
    insertCurve(Qt::Horizontal, Qt::yellow, 30.0);
    insertCurve(Qt::Horizontal, Qt::white, 70.0);

    replot();

    // ------------------------------------
    // We add a color bar to the left axis
    // ------------------------------------

    QwtScaleWidget *scaleWidget = (QwtScaleWidget *)axisWidget(yLeft);
    scaleWidget->setMargin(10); // area for the color bar
    d_colorBar = new ColorBar(Qt::Vertical, scaleWidget);
    d_colorBar->setRange(Qt::red, Qt::darkBlue);
#if QT_VERSION >= 0x040000
    d_colorBar->setFocusPolicy( Qt::TabFocus  );
#else
    d_colorBar->setFocusPolicy( QWidget::TabFocus  );
#endif

    connect(d_colorBar, SIGNAL(selected(const QColor &)),
        SLOT(setCanvasColor(const QColor &)));

    // we need the resize events, to lay out the color bar
    scaleWidget->installEventFilter(this);

    // ------------------------------------
    // We add a wheel to the canvas
    // ------------------------------------

    d_wheel = new QwtWheel(canvas());
    d_wheel->setOrientation(Qt::Vertical);
    d_wheel->setRange(-100, 100);
    d_wheel->setValue(0.0);
    d_wheel->setMass(0.2);
    d_wheel->setTotalAngle(4 * 360.0);

    connect(d_wheel, SIGNAL(valueChanged(double)),
        SLOT(scrollLeftAxis(double)));

    // we need the resize events, to lay out the wheel
    canvas()->installEventFilter(this);

#if QT_VERSION < 0x040000
    QWhatsThis::add(d_colorBar,
        "Selecting a color will change the background of the plot.");
    QWhatsThis::add(scaleWidget,
        "Selecting a value at the scale will insert a new curve.");
    QWhatsThis::add(d_wheel,
        "With the wheel you can move the visible area.");
    QWhatsThis::add(axisWidget(xBottom),
        "Selecting a value at the scale will insert a new curve.");
#else
    d_colorBar->setWhatsThis(
        "Selecting a color will change the background of the plot.");
    scaleWidget->setWhatsThis(
        "Selecting a value at the scale will insert a new curve.");
    d_wheel->setWhatsThis(
        "With the wheel you can move the visible area.");
    axisWidget(xBottom)->setWhatsThis(
        "Selecting a value at the scale will insert a new curve.");
#endif

}

void Plot::setCanvasColor(const QColor &c)
{
    setCanvasBackground(c);
    replot();
}

void Plot::scrollLeftAxis(double value)
{
    setAxisScale(yLeft, value, value + 100.0);
    replot();
}

bool Plot::eventFilter(QObject *object, QEvent *e)
{
    if ( e->type() == QEvent::Resize )
    {
        const QSize &size = ((QResizeEvent *)e)->size();
        if ( object == (QObject *)axisWidget(yLeft) )
        {
            const QwtScaleWidget *scaleWidget = axisWidget(yLeft);

            const int margin = 2;

            // adjust the color bar to the scale backbone
            const int x = size.width() - scaleWidget->margin() + margin;
            const int w = scaleWidget->margin() - 2 * margin;
            const int y = scaleWidget->startBorderDist();
            const int h = size.height() -
                scaleWidget->startBorderDist() - scaleWidget->endBorderDist();

            d_colorBar->setGeometry(x, y, w, h);
        }
        if ( object == canvas() )
        {
            const int w = 16;
            const int h = 50;
            const int margin = 2;

            const QRect cr = canvas()->contentsRect();
            d_wheel->setGeometry(
                cr.right() - margin - w, cr.center().y() - h / 2, w, h);
        }
    }

    return QwtPlot::eventFilter(object, e);
}

void Plot::insertCurve(int axis, double base)
{
    Qt::Orientation o;
    if ( axis == yLeft || axis == yRight )
        o = Qt::Horizontal;
    else
        o = Qt::Vertical;

    QRgb rgb = (uint)rand();
    insertCurve(o, QColor(rgb), base);
    replot();
}

void Plot::insertCurve(Qt::Orientation o,
    const QColor &c, double base)
{
    QwtPlotCurve *curve = new QwtPlotCurve();

    curve->setPen(c);
    curve->setSymbol(QwtSymbol(QwtSymbol::Ellipse,
        Qt::gray, c, QSize(8, 8)));

    double x[10];
    double y[sizeof(x) / sizeof(x[0])];

    for ( uint i = 0; i < sizeof(x) / sizeof(x[0]); i++ )
    {
        double v = 5.0 + i * 10.0;
        if ( o == Qt::Horizontal )
        {
            x[i] = v;
            y[i] = base;
        }
        else
        {
            x[i] = base;
            y[i] = v;
        }
    }

    curve->setData(x, y, sizeof(x) / sizeof(x[0]));
    curve->attach(this);
}