QT实例

#include "ditu.h"

#include

#include

#include

#include

#include

#include

ditu::ditu()

{

map.load("China.jpg");

zoom=50;

int width=map.width();

int height=map.height();

QGraphicsScene *scence=new QGraphicsScene(this);

scence->setSceneRect(-width/2,-height/2,width,height);

setScene(scene);

setCacheMode(CacheBackground);

QSlider *slider=new QSlider;

slider->setOrientation(Qt::Vertical);

slider->setRange(1,100);

slider->setTickInterval(10);

slider->setValue(50);

connect(slider,SIGNAL(valueChanged(int)),this,SLOT(slotZoom(int)));

QLabel *zoominLabel=new QLabel;

zoominLabel->setScaledContents(true);

zoominLabel->setPixmap(QPixmap("zoomin.png"));

QLabel *zoomoutLabel=new QLabel;

zoomoutLabel->setScaledContents(true);

zoomoutLabel->setPixmap(QPixmap("zoomout.png"));

QVBoxLayout *zoomLayout=new QFrame;

zoomLayout->addWidget(zoominLabel);

zoomLayout->addWidget(slider);

zoomLayout->addWidget(zoomoutLabel);

QHBoxLayout *mainLayout =new QHBoxLayout;

mainLayout->addLayout(zoomLayout);

mainLayout->addStretch();

mainLayout->setMargin(30);

mainLayout->setSpacing(10);

setLayout(mainLayout);

setWindowTitle("Map Widget");

setMinimumSize(600,400);

}

void ditu::slotZoom(int value)

{

qreal s;

if(value>zoom)

{

s=pow(1.01,(value-zoom));

}

else

{

s=pow(1/1.01,(zoom-value));

}

scale(s,s);

zoom=value;

}

void ditu::drawBackground(QPainter *painter, const QRectF &rect)

{

painter->drawPixmap(int(sceneRect().left(),int(sceneRect().top())),map); }

QPointF ditu::mapToMap(QPointF p)

{

QPointF latLon;

qreal w=sceneRect().width();

qreal h=sceneRect().height();

qreal lon=y1-((h/2+p.y()*abs(y1-y2)/h));

qreal lat=x1-((w/2+p.x()*abs(x1-x2)/w));

latLon.setX(lat);

latLon.setY(lon);

return latLon;

}

#ifndef DITU_H

#define DITU_H

#include

#include

class ditu : public QGraphicsView

{

Q_OBJECT

public:

ditu();

QPointF mapToMap(QPointF);

public slots:

void slotZoom(int);

protected:

void drawBackground(QPainter *painter, const QRectF &rect);

private:

QPixmap map;

qreal zoom;

double x1,y1;

double x2,y2;

};

#endif // DITU_H