Qt 实现跑马灯效果

参考某大神博客，针对自己的需求，实现了跑马灯效果。

效果如下：

 

思路：

1，启动定时器 进行刷新  

my_timer_id_ = startTimer(10, Qt::PreciseTimer);

2，每触发一次定时器，偏移量增加固定大小。  void Ticker::leftScrollTimerEvent(QTimerEvent *ev)

offset_ ++；

同时对控件面板上的内容左移1pixel。这样相当于控件面板左上角坐标为（0,0）；但是面板最左边坐标为（-1,0）

scroll(offset_,0);

3，每刷新一次 重新绘制文字

painter.drawText(x_coordinate,
                     height()/2-text_height/2,
                     text_width,
                     text_height,
                     Qt::AlignHCenter | Qt::AlignVCenter,
                     getSText());

4，当文字 移动到左侧消失时，重新从右侧开始移动

 if((offset_-fontMetrics().width(getSText()))>=width()){
            scroll(offset_,0);
            offset_ = 0;
            stop();
            emit finish();
        }

 

主要代码：

#pragma once

#include 
#include 

#include 

QT_BEGIN_NAMESPACE
class QHideEvent;
class QShowEvent;
class QTimerEvent;
class QPaintEvent;
QT_END_NAMESPACE

class Ticker : public QLabel
{
    Q_OBJECT

    //Q_PROPERTY(QString my_text_ READ getText WRITE setText)

public:
    explicit Ticker(QWidget *parent = 0);

    virtual QSize sizeHint() const;
    QString getSText() const;

    void setParam(const QString &sFontName,
                 const QString &sFontSize,
                  const QString &sColor,
                  const QString &sSpeed,
                  const QString &sText);

protected:
    virtual void hideEvent(QHideEvent* ev);
    virtual void timerEvent(QTimerEvent* ev);
    virtual void paintEvent(QPaintEvent* ev);

private:
    void leftScrollTimerEvent(QTimerEvent* ev);
    void leftScrollPaintEvent(QPaintEvent* ev);

private:
    //走马灯的偏移量
    int offset_;
    //定义的时钟id
    int my_timer_id_;

    QString m_sFontName;
    QString m_sFontSize;
    QString m_sColor;
    int m_sSpeed;
    QString m_sText;

public slots:
    void start();
    void stop();

signals:
    void finish();
};

#include "ticker.h"

#include 
#include 
#include 
#include 
#include 
#include 


Ticker::Ticker(QWidget *parent) :
    QLabel(parent),
    offset_(0),
    my_timer_id_(0),
    m_sText(QStringLiteral("欢迎光临 ")),
    m_sFontSize("50"),
    m_sColor("255,0,0,255"),
    m_sFontName("SimSun")
{

}

void Ticker::start()
{
    //创建timer，并返回timer的id
    my_timer_id_ = startTimer(10, Qt::PreciseTimer);
}

void Ticker::stop()
{
    killTimer(my_timer_id_);
    my_timer_id_ = 0;
}

QSize Ticker::sizeHint() const
{
    //2倍高度
    /*int height = fontMetrics().size(Qt::TextSingleLine, getSText()).height();
    int width = fontMetrics().size(Qt::TextSingleLine, getSText()).width();
    return QSize(width * 2.3, 5 * height);*/

    //根据文本内容，设定文本框显示尺寸
    return (fontMetrics().size(Qt::TextSingleLine, getSText()));
}


void Ticker::hideEvent(QHideEvent *ev)
{
    Q_UNUSED(ev)

    //根据timer的id终止timer
    killTimer(my_timer_id_);
    my_timer_id_ = 0;
}

void Ticker::timerEvent(QTimerEvent *ev)
{
    leftScrollTimerEvent(ev);
}

void Ticker::paintEvent(QPaintEvent *ev)
{
    leftScrollPaintEvent(ev);
}

void Ticker::leftScrollTimerEvent(QTimerEvent *ev)
{
    if (ev->timerId() == my_timer_id_) {
        //++offset_;
        //速度设置
        if(m_sSpeed<0)
            m_sSpeed=0;
        if(m_sSpeed>10)
            m_sSpeed=10;

        offset_+=m_sSpeed;
        if((offset_-fontMetrics().width(getSText()))>=width()){
            scroll(offset_,0);
            offset_ = 0;
            stop();
            emit finish();
        }

        scroll(-1, 0);
    } else {
        QWidget::timerEvent(ev);
    }
}

void Ticker::leftScrollPaintEvent(QPaintEvent *ev)
{
    Q_UNUSED(ev)

    QPainter painter(this);

    const int text_width(fontMetrics().width(getSText()));
    const int text_height(fontMetrics().height());

    if (text_width < 1) {
        return;
    }

    int x_coordinate(width()-offset_);

    painter.drawText(x_coordinate,
                     height()/2-text_height/2,
                     text_width,
                     text_height,
                     Qt::AlignHCenter | Qt::AlignVCenter,
                     getSText());
}

QString Ticker::getSText() const
{
    return m_sText;
}

void Ticker::setParam(const QString &sFontName, const QString &sFontSize, const QString &sColor, const QString &sSpeed, const QString &sText)
{
    m_sFontName = sFontName;
    m_sText = sText;
    m_sFontSize = sFontSize;
    m_sColor = sColor;
    m_sSpeed = sSpeed.toInt();

    QString r="255",g="0",b="0",a="255";
    QStringList colorList = m_sColor.split(":");
    if(colorList.count()==4){
        r=colorList.at(0);
        g=colorList.at(1);
        b=colorList.at(2);
        a=colorList.at(3);
    }

    QString styleStr = QString("background-color: rgb(0, 0, 0);\n"
                               "color: rgb(%1, %2, %3,%4);\n"
                               "font: %5pt \"%6\";").arg(r).arg(g).arg(b).arg(a).arg(m_sFontSize).arg(m_sFontName);
    qDebug()<<"style:"<setStyleSheet(styleStr);

    //布局管理器更新布局设置
    updateGeometry();
}

 

参考：https://my.oschina.net/weiweiqiao/blog/334931