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我正在为 QtCreator 中的实时输入编写一个绘图窗口，其中数据波形在用户指定的周期内以循环方式覆盖自身。

实际的绘图仪和轴初始化工作得很好，但是在每个周期结束时更新时间轴时遇到了一些麻烦。我认为擦除标签区域中的所有数据并使用新值重新绘制会起作用，但是在第一个周期结束时会擦除整个轴。我怀疑我使用 QPainter 存在一些问题。

第一次发帖，轻点我。

void T_AxisWidget::initAxis(double window_period) { period = window_period; t_pixmap = QPixmap(大小()); t_pixmap.fill(Qt::black);

QPainter painter(&t_pixmap);
painter.initFrom(this);
painter.setPen(Qt::red);
painter.drawLine(0, 0, size().width(), 0);
painter.drawLine(0, 0, 0, TICK_LENGTH); //always draw first tick at origin
int tick_interval = size().width()/(num_ticks);
int remainder = (size().width()%(num_ticks))-1; //pixels to be skipped to cover entire axis

painter.drawText(0, TICK_LENGTH+2, tick_interval/2, size().height()-TICK_LENGTH+2,
                   Qt::AlignLeft | Qt::AlignTop,
                   QString::number(0));

qDebug() << "width = " << size().width();
qDebug() << "interval = " << size().width()/(num_ticks);

for(int i=tick_interval; i<=size().width()-tick_interval; i+=tick_interval) {
    if (remainder>0) {
        ++i; //space ticks an extra pixel apart initially to achieve an even spread
        --remainder;

        qDebug() << "remainder = " << remainder;
        qDebug() << "tick = " << i;
    }
    painter.drawLine(i, 0, i, TICK_LENGTH);
    painter.drawText(i-(tick_interval/2), TICK_LENGTH+2, tick_interval, size().height()-TICK_LENGTH+2,
                       Qt::AlignHCenter | Qt::AlignTop,
                       QString::number((period/(double)num_ticks)*(i/tick_interval)));
 }
 painter.drawLine(size().width()-1, 0, size().width()-1, TICK_LENGTH);
 painter.drawText(size().width()-tick_interval/2, TICK_LENGTH+2, tick_interval/2, size().height()-TICK_LENGTH+2,
                       Qt::AlignRight | Qt::AlignTop,
                       QString::number(period)); }

void T_AxisWidget::setTValues (int multiplier) { double start = period*multiplier; int tick_interval = period/num_ticks;

QPainter painter(&t_pixmap);
painter.initFrom(this);
painter.setPen(Qt::red);
QRect eraseblock(0, TICK_LENGTH+2, size().width(), size().height());
painter.eraseRect(eraseblock);

painter.drawText(0, TICK_LENGTH+2, tick_interval/2, size().height()-TICK_LENGTH+2,
               Qt::AlignLeft | Qt::AlignTop,
               QString::number(start));


for(int i=1; i<num_ticks; i++) {
    painter.drawText(i*tick_interval-(tick_interval/2), TICK_LENGTH+2, tick_interval, size().height()-TICK_LENGTH+2,
                     Qt::AlignHCenter | Qt::AlignTop,
                     QString::number(start+(i*period/(double)num_ticks)));
}
painter.drawText(size().width()-(tick_interval/2), TICK_LENGTH+2, tick_interval/2, size().height()-TICK_LENGTH+2,
                 Qt::AlignRight | Qt::AlignTop,
                 QString::number(period*multiplier));

}

void T_AxisWidget::paintEvent(QPaintEvent * /* event */) { QStylePainterpainter(this); 画家.drawPixmap(0, 0, t_pixmap); }

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