qgps_satmap.cc

在linux系统下开发的GPS接收程序,具有良好的图形操作界面.

//------------------------------------------------------------------------
// qgpssatmap.cc: implementation of QGpsSatMap class
//
//	- programmed by Boyoon Jung
//------------------------------------------------------------------------
#include "qgps_satmap.h"
#include <qpainter.h>
#include <cmath>


// constructor
QGpsSatMap::QGpsSatMap(QWidget *parent, const char *name, WFlags f)
	: QFrame(parent, name, f)
{
    // initialization
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    setBackgroundMode(NoBackground);
}


// destructor
QGpsSatMap::~QGpsSatMap(void)
{
}


// when the size of window changes
void QGpsSatMap::resizeEvent (QResizeEvent *e)
{
    // resize the local data buffer
    _pixmap.resize(e->size());

    // resize north/south indicators
    cx = e->size().width() / 2;
    cy = e->size().height() / 2;
    radius = (cx < cy) ? (cx-20) : (cy-20);	// boundary: 10 pixels
}


// draw contents
void QGpsSatMap::drawContents(QPainter *p)
{
    const static int unitR = 100;

    // for double buffering
    _painter.begin(&_pixmap);

    // clear the buffer
    _painter.setPen(NoPen);
    _painter.setBrush(darkBlue);
    _painter.drawRect(0, 0, _pixmap.size().width(), _pixmap.size().height());

    // set the coordinates
    _painter.translate(cx, cy);

    // draw the center position
    _painter.setPen(darkGray);
    _painter.setBrush(NoBrush);
    _painter.drawLine(-3,0, 3,0);
    _painter.drawLine(0,-3, 0,3);

    // draw concentric circles
    for (double i=radius/4; i<=radius; i+=radius/4)
	_painter.drawEllipse(-i,-i, 2*i,2*i);

    // draw E/W/S/N marks
    _painter.save();
    _painter.drawText(0, -radius-5, "N");
    _painter.rotate(90);
    _painter.drawText(0, -radius-5, "E");
    _painter.rotate(90);
    _painter.drawText(0, -radius-5, "S");
    _painter.rotate(90);
    _painter.drawText(0, -radius-5, "W");
    _painter.restore();

    // draw satellites
    QString prn;
    for (int i=0; i<nsat; i++)
    {
	// set color based on if it is in use or not
	if (active[i]) {
	    _painter.setPen(red);
	    _painter.setBrush(red);
	}
	else {
	    _painter.setPen(white);
	    _painter.setBrush(white);
	}

	// compute the position of satellites in image coordinates
	double d = radius * cos(sat[i].elevation*M_PI/180);
	int x = int(d * cos((sat[i].azimuth-90)*M_PI/180));
	int y = int(d * sin((sat[i].azimuth-90)*M_PI/180));
	_painter.drawEllipse(x-5,y-5, 10,10);
	_painter.drawText(x+5, y, prn.setNum(sat[i].prn));
    }

    // draw them on the screen
    _painter.end();
    p->drawPixmap(0, 0, _pixmap);
}


// inline function to check if a PRN is active
inline bool is_active(int prn, int used[])
{
    for (int i=0; i<12 && used[i] >= 0; i++)
	if (used[i] == prn) return true;
    return false;
}


// update info
void QGpsSatMap::updateSatellites(int nsat, satinfo_t sat[], int prn_used[])
{
    // store the information
    this->nsat = nsat;
    for (int i=0; i<nsat; i++) {
	this->sat[i] = sat[i];
	this->active[i] = is_active(sat[i].prn, prn_used);
    }

    // update the screen
    update();
}