Qt:地图浏览器

Qt:地图浏览器

2010-08-06 04:36

 

 

(源代码和界面之间有一些差异)

参照Linux窗口程序设计---Qt4精彩实例分析中P187的例39"地图浏览器"；

和实例不同的是，这里增加了地图的平移功能。在Qt的Demo中，通过setDragMode(QGraphicsView::ScrollHandDrag)即可实现平移，但是，如果需要mouseMoveEvent事件的话，这个方法就不可用，理由如下：

/*gps.h*/

#include <QtGui>
#include "_5waybutton.h"

class Gps:public QGraphicsView
{
    Q_OBJECT
public:
    Gps();
    ~Gps();
    //
    void mouseMoveEvent(QMouseEvent *event);
    void mousePressEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);
    void mouseDoubleClickEvent(QMouseEvent *event);
    void wheelEvent(QWheelEvent *event);
    //
    void load_map();
    void drawBackground(QPainter *painter, const QRectF &rect);
    //
    QGraphicsScene *scene;
    QPixmap map;
    _5WayButton *_5waybutton;
    QSlider *slider_zoom;
    QFrame *frame_coor;
    QLabel *label_coor;
    QLabel *label_latitude;
    QLabel *label_parallel;
    QPoint point_start;
    //
    int zoom;
    int center_x;
    int center_y;
public slots:
    void slot_zoom(int value);
    void slot_up();
    void slot_left();
    void slot_right();
    void slot_down();
    void slot_center();
};

/*gps.cpp*/

#include "gps.h"

Gps::Gps()
{
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    load_map();
    scene=new QGraphicsScene();
    scene->setSceneRect(-map.width()/2,-map.height()/2,map.width(),map.height());
    scene->setItemIndexMethod(QGraphicsScene::NoIndex);
    setScene(scene);
    setRenderHint(QPainter::Antialiasing);
    setCacheMode(QGraphicsView::CacheBackground);
    //setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
    //setDragMode(QGraphicsView::ScrollHandDrag);
    //setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Colliding Mice"));
    //
    QLabel *label_zoomout=new QLabel(tr(" 放大"));
    label_zoomout->setFont(QFont("Arial",12,QFont::Bold));
    //
    QLabel *label_zoomin=new QLabel(tr(" 缩小"));
    label_zoomin->setFont(QFont("Arial",12,QFont::Bold));
    //
    slider_zoom=new QSlider();
    slider_zoom->setOrientation(Qt::Vertical);
    slider_zoom->setRange(1,400);
    slider_zoom->setTickInterval(5);
    slider_zoom->setValue(200);
    slider_zoom->setFixedSize(40,400);
    connect(slider_zoom,SIGNAL(valueChanged(int)),this,SLOT(slot_zoom(int)));
    zoom=200;
    //
    center_x=0;
    center_y=0;
    //
    frame_coor=new QFrame();
    //
    label_coor=new QLabel(tr("地理坐标"));
    label_coor->setFont(QFont("Arial",10,QFont::Bold));
    label_latitude=new QLabel(tr("纬度: "));
    label_latitude->setFont(QFont("Arial",10,QFont::Bold));
    label_parallel=new QLabel(tr("经度: "));
    label_parallel->setFont(QFont("Arial",10,QFont::Bold));
    //
    QVBoxLayout *layout_frame=new QVBoxLayout();
    layout_frame->addWidget(label_coor);
    layout_frame->addWidget(label_latitude);
    layout_frame->addWidget(label_parallel);
    frame_coor->setLayout(layout_frame);
    //
    _5waybutton=new _5WayButton();
    connect(_5waybutton->navibutton_up,SIGNAL(clicked()),this,SLOT(slot_up()));
    connect(_5waybutton->navibutton_left,SIGNAL(clicked()),this,SLOT(slot_left()));
    connect(_5waybutton->navibutton_right,SIGNAL(clicked()),this,SLOT(slot_right()));
    connect(_5waybutton->navibutton_down,SIGNAL(clicked()),this,SLOT(slot_down()));
    connect(_5waybutton->navibutton_center,SIGNAL(clicked()),this,SLOT(slot_center()));
    //
    QVBoxLayout *layout_zoom=new QVBoxLayout();
    layout_zoom->addWidget(frame_coor);
    layout_zoom->addWidget(_5waybutton);
    layout_zoom->addWidget(label_zoomout);
    layout_zoom->addWidget(slider_zoom);
    layout_zoom->addWidget(label_zoomin);
    layout_zoom->setSpacing(0);
    //
    QHBoxLayout *layout_main=new QHBoxLayout();
    layout_main->addLayout(layout_zoom);
    layout_main->addStretch();
    layout_main->setSpacing(0);
    setLayout(layout_main);
}

Gps::~Gps()
{
}

void Gps::load_map()
{
    map.load(":/image/wuhan.jpg");
}

void Gps::drawBackground(QPainter *painter, const QRectF &rect)
{
    painter->drawPixmap(int(sceneRect().left()),int(sceneRect().top()),map);
}

void Gps::slot_zoom(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 Gps::mouseMoveEvent(QMouseEvent *event)
{
    QPointF point_scene=this->mapToScene(event->pos());
    label_latitude->setText(tr("纬度: ")+QString::number(point_scene.y()+map.height()/2));
    label_parallel->setText(tr("经度: ")+QString::number(point_scene.x()+map.width()/2));
    if(cursor().shape()==Qt::OpenHandCursor)
    {
        center_x+=5*(event->pos().x()-point_start.x());
        center_x<-map.width()/2?center_x=-map.width()/2:1;
        center_x>map.width()/2?center_x=map.width()/2:1;
        center_y+=5*(event->pos().y()-point_start.y());
        center_y<-map.height()/2?center_y=-map.height()/2:1;
        center_y>map.height()/2?center_y=map.height()/2:1;
        centerOn(center_x,center_y);
        point_start=event->pos();
    }

}

void Gps::mousePressEvent(QMouseEvent *event)
{
    point_start=event->pos();
    setCursor(Qt::OpenHandCursor);
}

void Gps::mouseReleaseEvent(QMouseEvent *event)
{
    this->setCursor(Qt::ArrowCursor);
}

void Gps::mouseDoubleClickEvent(QMouseEvent *event)
{
    slot_center();
}

void Gps::wheelEvent(QWheelEvent *event)
{
    int z=slider_zoom->value()+event->delta()/10;
    z>400?z=400:1;
    z<1?z=1:1;
    this->slider_zoom->setValue(z);
}

void Gps::slot_up()
{
    center_y<-map.height()/2?center_y=-map.height()/2:center_y-=map.height()/10;
    centerOn(center_x,center_y);
}

void Gps::slot_left()
{
    center_x<-map.width()/2?center_x=-map.width()/2:center_x-=map.width()/10;
    centerOn(center_x,center_y);
}

void Gps::slot_right()
{
    center_x>map.width()/2?center_x=map.width()/2:center_x+=map.width()/10;
    centerOn(center_x,center_y);
}

void Gps::slot_down()
{
    center_y>map.height()/2?center_y=map.height()/2:center_y+=map.height()/10;
    centerOn(center_x,center_y);
}

void Gps::slot_center()
{
    slider_zoom->setValue(200);
    center_x=0;
    center_y=0;
    centerOn(center_x,center_y

}