Qt C++ 图像显示组件 paintEvent 事件优化

void CImageShowWidget::paintEvent(QPaintEvent* event) { QWidget::paintEvent(event); if (m_pixmap.isNull()) { ui->ImageLab->clear(); return; }

QPixmap pix = m_pixmap.scaled(ui->ImageLab->size());
QPainter pLine(ui->ImageLab);
pLine.drawPixmap(0, 0, pix);
pLine.setRenderHint(QPainter::Antialiasing);
pLine.setRenderHint(QPainter::SmoothPixmapTransform);

// 绘制通道id到图上
DrawChannelNum(pLine, m_channelID);

// 绘制ROI矩形
if (m_RoiRect.width() > 0 && m_RoiRect.height() > 0)
{
    if (m_bChangeROIColor)
    {
        pLine.setPen(Qt::green);
        float fWScale = (float)m_pixImage.width() / (float)ui->ImageLab->width();
        float fHScale = (float)m_pixImage.height() / (float)ui->ImageLab->height();
        m_fRectROIScale = fWScale > fHScale ? fHScale : fWScale;
    }
    else
    {
        pLine.setPen(Qt::red);
    }
    pLine.setBrush(Qt::NoBrush);
    QRect rectRoi = m_RoiRect;
    rectRoi.setX(m_RoiRect.x() - ui->ImageLab->x());
    rectRoi.setY(m_RoiRect.y() - ui->ImageLab->y());
    rectRoi.setWidth(m_RoiRect.width());
    rectRoi.setHeight(m_RoiRect.height());
    pLine.drawRect(rectRoi);
}

// 绘制角度
if (m_degDrawingPoint.size() > 1 || m_degPoint.size() > 0)
{
    pLine.setPen(Qt::red);
    pLine.setBrush(Qt::NoBrush);
    if (m_degDrawingPoint.size() > 1)
    {
        if (m_degDrawingPoint.size() == 2)
        {
            int iX = ui->ImageLab->x();
            int iY = ui->ImageLab->y();
            pLine.drawLine(m_degDrawingPoint[0].x() - ui->ImageLab->x(), m_degDrawingPoint[0].y() - ui->ImageLab->y(), m_degDrawingPoint[1].x() - ui->ImageLab->x(), m_degDrawingPoint[1].y() - ui->ImageLab->y());
        }
        else if (m_degDrawingPoint.size() == 3)
        {
            pLine.drawLine(m_degDrawingPoint[0].x() - ui->ImageLab->x(), m_degDrawingPoint[0].y() - ui->ImageLab->y(), m_degDrawingPoint[1].x() - ui->ImageLab->x(), m_degDrawingPoint[1].y() - ui->ImageLab->y());
            pLine.drawLine(m_degDrawingPoint[0].x() - ui->ImageLab->x(), m_degDrawingPoint[0].y() - ui->ImageLab->y(), m_degDrawingPoint[2].x() - ui->ImageLab->x(), m_degDrawingPoint[2].y() - ui->ImageLab->y());
            QVector<QPoint> posResult = GetArcPoint(m_degDrawingPoint);
            if (posResult.size() == 3)
            {
                ArcInfo  arcinfo = DrawArc(posResult[1] - ui->ImageLab->pos(), posResult[2] - ui->ImageLab->pos(), posResult[0] - ui->ImageLab->pos(), false);
                pLine.drawArc(arcinfo.rectangle, arcinfo.startAngle * 16, arcinfo.spanAngle * 16);
                pLine.drawText(m_degDrawingPoint[0] - ui->ImageLab->pos(), QString::number(arcinfo.spanAngle) + "°");
            }
        }
    }
    if (m_degPoint.size() > 0)
    {
        for (size_t i = 0; i < m_degPoint.size(); i++)
        {
            QVector<QPoint> posInt = m_degPoint[i];
            if (posInt.size() == 3)
            {
                pLine.drawLine(posInt[0].x() - ui->ImageLab->x(), posInt[0].y() - ui->ImageLab->y(), posInt[1].x() - ui->ImageLab->x(), posInt[1].y() - ui->ImageLab->y());
                pLine.drawLine(posInt[0].x() - ui->ImageLab->x(), posInt[0].y() - ui->ImageLab->y(), posInt[2].x() - ui->ImageLab->x(), posInt[2].y() - ui->ImageLab->y());
                QVector<QPoint> posResult = GetArcPoint(posInt);
                if (posResult.size() == 3)
                {
                    ArcInfo  arcinfo = DrawArc(posResult[1] - ui->ImageLab->pos(), posResult[2] - ui->ImageLab->pos(), posResult[0] - ui->ImageLab->pos(), false);
                    pLine.drawArc(arcinfo.rectangle, arcinfo.startAngle * 16, arcinfo.spanAngle * 16);
                    pLine.drawText(posInt[0] - ui->ImageLab->pos(), QString::number(arcinfo.spanAngle) + "°");
                }
            }
        }
    }
}

// 绘制Profile线段
if (m_DrawProfilePoint.size() == 2)
{
    pLine.setPen(Qt::red);
    pLine.setBrush(Qt::NoBrush);
    if (m_DrawProfilePoint.size() == 2)
    {
        pLine.drawLine(m_DrawProfilePoint[0].x() - ui->ImageLab->x(), m_DrawProfilePoint[0].y() - ui->ImageLab->y(), m_DrawProfilePoint[1].x() - ui->ImageLab->x(), m_DrawProfilePoint[1].y() - ui->ImageLab->y());
    }
}

// 绘制LineSegment
if (m_LineSegmentPoint.size() == 2)
{
    pLine.setPen(Qt::red);
    pLine.setBrush(Qt::NoBrush);
    if (m_LineSegmentPoint.size() == 2)
    {
        pLine.drawLine(m_LineSegmentPoint[0].x() - ui->ImageLab->x(), m_LineSegmentPoint[0].y() - ui->ImageLab->y(), m_LineSegmentPoint[1].x() - ui->ImageLab->x(), m_LineSegmentPoint[1].y() - ui->ImageLab->y());
        float iDiffX = abs(m_LineSegmentPoint[1].x() - m_LineSegmentPoint[0].x())*m_pixmap.width() / pix.width();
        float iDiffY = abs(m_LineSegmentPoint[1].y() - m_LineSegmentPoint[0].y())*m_pixmap.height() / pix.height();
        float fLength = sqrt(iDiffX*iDiffX + iDiffY * iDiffY);
        if (fLength > 0)
        {
            if (m_PixelWidth > 0)
            {
                pLine.drawText(QPoint(m_LineSegmentPoint[1].x() - ui->ImageLab->x(), m_LineSegmentPoint[1].y() - ui->ImageLab->y()), QString::number(fLength * m_PixelWidth) + "μm");
            }
            else
            {
                pLine.drawText(QPoint(m_LineSegmentPoint[1].x() - ui->ImageLab->x(), m_LineSegmentPoint[1].y() - ui->ImageLab->y()), QString::number(fLength) + "pix");
            }
        }
        //if (m_PixelWidth > 0)
    //         {
    //             float iDiffX = abs(m_LineSegmentPoint[1].x() - m_LineSegmentPoint[0].x())*m_pixmap.width() / pix.width();
    //             float iDiffY = abs(m_LineSegmentPoint[1].y() - m_LineSegmentPoint[0].y())*m_pixmap.height() / pix.height();
    //             float fLength = sqrt(iDiffX*iDiffX + iDiffY * iDiffY);
    //             if (fLength > 0)
    //             {
    //                 pLine.drawText(QPoint(m_LineSegmentPoint[1].x() - ui->ImageLab->x(), m_LineSegmentPoint[1].y() - ui->ImageLab->y()), QString::number(fLength) + "μm");
    //             }
    //         }
    }
}
if (m_bShowScale && m_struScaleStyleSheet.m_bShow)
{
    pLine.setBrush(Qt::NoBrush);
    DrawScale(pLine);
}
g_mutex.lock();
m_pix = pix;
g_mutex.unlock();
if (m_CropUpRect.isValid())
{
    QRect rectRoi = m_CropUpRect;
    rectRoi.setX(m_CropUpRect.x() - ui->ImageLab->x());
    rectRoi.setY(m_CropUpRect.y() - ui->ImageLab->y());
    rectRoi.setWidth(m_CropUpRect.width());
    rectRoi.setHeight(m_CropUpRect.height());
    //QPixmap pixCrop = pix.copy(rectRoi);
    //emit Signal_setPixmap(pixCrop.scaled(ui->ImageLab->size()));
    emit Signal_updateImage(rectRoi);
}
else
{
    emit Signal_updateImage();
    //emit Signal_setPixmap(pix);
}

}