clockface.cpp

程序代码使用说明： (1)所有源代码目录下都提供了Makefile（非Qt）

#include "ClockFace.h"

#include <QLayout>
#include <QPainter>
#include <QImage>

#include <QPaintEvent>

#include <math.h>

const double deg2rad = 0.017453292519943295769; // pi/180

ClockFace::ClockFace(QWidget *parent)
    : QFrame(parent), isEvent(true)
{
    setMinimumSize(50,50);
    setSizePolicy(QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding));
    
    currTime = QTime::currentTime();
}

void ClockFace::paintEvent( QPaintEvent *event )
{
    QPainter paint(this);
    if (event->rect().intersects(contentsRect())) {
        paint.setClipRegion(event->region().intersect(contentsRect()));
        drawContents(&paint);
    }
}

void ClockFace::drawContents( QPainter *pp )
{
    pp->setRenderHint(QPainter::Antialiasing);

    QRect r = contentsRect();
    int size = qMin(r.width(), r.height());
    QPoint offs((r.width()-size)/2, (r.height()-size)/2);
    QRect pr(0, 0, size, size);

    pp->save();
    pp->translate(offs.x(), offs.y());
    pp->setRenderHint(QPainter::Antialiasing);

    isEvent = true;

    QPoint center( size / 2, size / 2 );

    const int w_tick = pr.width()/150+1;
    const int w_sec = pr.width()/200+1;
    const int w_min = pr.width()/100+1;
    const int w_hour = pr.width()/50+1;

    QPoint l1( pr.x() + pr.width() / 2, pr.y() + 2 );
    QPoint l2( pr.x() + pr.width() / 2, pr.y() + 6 );

    QPoint h1( pr.x() + pr.width() / 2, pr.y() + pr.height() / 4 );
    QPoint h2( pr.x() + pr.width() / 2, pr.y() + pr.height() / 2 );

    QPoint m1( pr.x() + pr.width() / 2, pr.y() + pr.height() / 9 );
    QPoint m2( pr.x() + pr.width() / 2, pr.y() + pr.height() / 2 );

    QPoint s1( pr.x() + pr.width() / 2, pr.y() + 8 );
    QPoint s2( pr.x() + pr.width() / 2, pr.y() + pr.height() / 2 );

    QColor color(Qt::black);
    QTime time = currTime;

    if ( isEvent || prevTime.minute() != currTime.minute()
            || prevTime.hour() != currTime.hour()
            || qAbs(prevTime.secsTo(currTime)) > 1 ) 
    {
        // draw ticks
        pp->setPen(QPen(color, w_tick));
        for ( int i = 0; i < 12; i++ )
            pp->drawLine( rotate( center, l1, i * 30 ), rotate( center, l2, i * 30 ) );

        // draw hour pointer
        h1 = rotate( center, h1, 30 * ( time.hour() % 12 ) + time.minute() / 2 );
        h2 = rotate( center, h2, 30 * ( time.hour() % 12 ) + time.minute() / 2 );
        pp->setPen(QPen(Qt::green, w_hour));
        pp->drawLine(h1, h2);

        // draw minute pointer
        m1 = rotate( center, m1, time.minute() * 6 );
        m2 = rotate( center, m2, time.minute() * 6 );
        pp->setPen(QPen(Qt::blue, w_min));
        pp->drawLine(m1, m2);
    }

    pp->restore();

    prevTime = currTime;

    pp->setClipping(false);

    // draw second pointer
    s1 = rotate( center, s1, time.second() * 6 );
    s2 = rotate( center, s2, time.second() * 6 );
    pp->setPen(QPen(Qt::red, w_sec));
    pp->drawLine(s1+offs, s2+offs);

    // cap
    pp->setBrush(color);
    pp->drawEllipse( center.x()-w_hour/2+offs.x(), center.y()-w_hour/2+offs.y(), w_hour, w_hour );

    isEvent = true;
}

void ClockFace::display( const QTime& t )
{
    currTime = t;
    if (isVisible()) 
        isEvent = false;
    repaint();
}

QPoint ClockFace::rotate( QPoint c, QPoint p, int a )
{
    double angle = deg2rad * ( - a + 180 );
    double nx = c.x() - ( p.x() - c.x() ) * cos( angle ) -
                ( p.y() - c.y() ) * sin( angle );
    double ny = c.y() - ( p.y() - c.y() ) * cos( angle ) +
                ( p.x() - c.x() ) * sin( angle );
    return QPoint( int(nx), int(ny) );
}