Qt 水平滚动字幕

转载自：http://blog.sina.com.cn/s/blog_6294abe701015h93.html
/ widget.h"
#ifndef WIDGET_H#define WIDGET_H #include <QWidget>  namespace Ui { class Widget; }  class Widget : public QWidget { Q_OBJECT   Q_PROPERTY(QString text READ text WRITE setText)   public: explicit Widget(QWidget *parent = 0); ~Widget(); void setText(const QString &newText); QString text() const { return myText; } QSize sizeHint() const;  protected: void paintEvent(QPaintEvent *event); void timerEvent(QTimerEvent *event); void showEvent(QShowEvent *event); void hideEvent(QHideEvent *event);  private: QString myText; int offset; int myTimerId;  private: Ui::Widget *ui;   };  #endif // WIDGET_H     // widget.cpp #include "widget.h" #include "ui_widget.h" #include <QPainter>  #include <qcoreevent.h>   Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this);   offset = 0; myTimerId = 0;   }  Widget::~Widget() { delete ui; }  void Widget::setText(const QString &newText) { myText = newText; update(); updateGeometry(); }  QSize Widget::sizeHint() const { return fontMetrics().size(0, text()); }  void Widget::paintEvent(QPaintEvent * ) { QPainter painter(this);   int textWidth = fontMetrics().width(text()); if (textWidth < 1) return; int x = -offset; while (x < width()) { painter.drawText(x, 0, textWidth, height(), Qt::AlignLeft | Qt::AlignVCenter, text()); x += textWidth; } }  void Widget::showEvent(QShowEvent * ) { myTimerId = startTimer(30); }  void Widget::timerEvent(QTimerEvent *event) { if (event->timerId() == myTimerId) { ++offset; if (offset >= fontMetrics().width(text())) offset = 0; scroll(-1, 0); } else { QWidget::timerEvent(event); } }  void Widget::hideEvent(QHideEvent * ) { killTimer(myTimerId); myTimerId = 0; }      // main.cp #include <QtGui/QApplication> #include "widget.h" #include <QLabel> #include <QGridLayout> #include <QTextCodec> #include <QIcon> #include <QPushButton>  int main(int argc, char *argv[]) { QApplication a(argc, argv); Widget w;   w.setWindowTitle(QObject::tr("Ticker")); w.setText(QObject::tr("How long it lasted was impossible to " "say ++ "));   w.show();   return a.exec();  }