plot.cpp

QWT5.01用于Qt开发的二维图形库程序

#include <qfiledialog.h>
#include <qwt_plot_svgitem.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_layout.h>
#include <qwt_plot_canvas.h>
#include <qwt_plot_panner.h>
#include <qwt_plot_magnifier.h>
#include "plot.h"

Plot::Plot(QWidget *parent):
    QwtPlot(parent),
    d_mapItem(NULL),
    d_mapRect(0.0, 0.0, 100.0, 100.0) // something
{   
#if 1
    /*
       d_mapRect is only a reference for zooming, but
       the ranges are nothing useful for the user. So we
       hide the axes.
     */
    plotLayout()->setCanvasMargin(0);
    for ( int axis = 0; axis < QwtPlot::axisCnt; axis++ )
        enableAxis(axis, false);
#else
    QwtPlotGrid *grid = new QwtPlotGrid();
    grid->attach(this);
#endif

    /*
      Navigation:
      
      Left Mouse Button: Panning
      Mouse Wheel:       Zooming In/Out
      Right Mouse Button: Reset to initial 
    */

    (void)new QwtPlotPanner(canvas());
    (void)new QwtPlotMagnifier(canvas());

#if QT_VERSION >= 0x040000
    using namespace Qt;
#endif
    canvas()->setFocusPolicy(WheelFocus);
    rescale();
}

void Plot::loadSVG()
{
    QString dir;
#if 0
    dir = "/dw/svg";
#endif
#if QT_VERSION >= 0x040000
    const QString fileName = QFileDialog::getOpenFileName( NULL,
        "Load a Scaleable Vector Graphic (SVG) Map",
        dir, "SVG Files (*.svg)");
#else
    const QString fileName = QFileDialog::getOpenFileName( 
        dir, "SVG Files (*.svg)", NULL, NULL, 
        "Load a Scaleable Vector Graphic (SVG) Map" );
#endif
    if ( !fileName.isEmpty() )
    {
        if ( d_mapItem == NULL )
        {
            d_mapItem = new QwtPlotSvgItem();
            d_mapItem->attach(this);
        }

        d_mapItem->loadFile(d_mapRect, fileName);
        rescale();

        replot();
    }
}

void Plot::rescale()
{
    setAxisScale(QwtPlot::xBottom,
        d_mapRect.left(), d_mapRect.right());
    setAxisScale(QwtPlot::yLeft,
        d_mapRect.top(), d_mapRect.bottom());
}