本文例項為大家分享了Qt圓盤進度條的具體程式碼，供大家參考，具體內容如下

自定義控制元件二：圓盤進度條

上效果圖：

主要思路：使用qpainter根據圖形需求 畫圓和圓弧，畫指標（多邊形，指定座標即可），根據具體的value值旋轉座標系，使指標達到旋轉效果，旋轉度數是根據value值，總共360度，佔比求得。最中間需要畫文字上去，每次更新value時呼叫update（）方法，重繪介面。

主要程式碼：CMPassrate1.cpp

void CMPassrate1::paintEvent(QPaintEvent *event){
  int width = this->width();
  int height = this->height();
  int side = qMin(width,height);

  QPainter painter(this);
  painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
  painter.translate(width / 2,height / 2);
  painter.scale(side / 200.0,side / 200.0);

  //繪製外圓
  paintSide(&painter);
  paintOutE(&painter);
  
  paintLine(&painter);//繪製刻度線
  paintInE(&painter);
  paintPoint(&painter);//繪製指標
  paintTextE(&painter);//繪製文字所在的圓
  paintText(&painter);//繪製文字
  paintValue(&painter);//繪製value對應的填充角度
}

void CMPassrate1::paintSide(QPainter *painter){
  int radis = outRadis;
  QRect rect(-radis,-radis,radis*2,radis*2);
  painter->save();
  painter->setBrush(QBrush(QColor("#505050")));
  painter->setPen(Qt::NoPen);
  painter->drawEllipse(rect);
  painter->restore();
}

void CMPassrate1::paintOutE(QPainter *painter){
  int radis = outRadis-side;
  QRect rect(-radis,radis*2);
  painter->save();
  painter->setBrush(QBrush(QColor("#868686")));
  painter->setPen(Qt::NoPen);
  painter->drawEllipse(rect);
  painter->restore();
}

void CMPassrate1::paintLine(QPainter *painter){
  int lineStart = outRadis-3;
  painter->save();
  painter->setPen(QColor("#868686"));
  int range = 360/12;
  for(int i = 0;i<12;i++){
    painter->rotate(range);
    painter->drawLine(QPoint(lineStart,0),QPoint(outRadis,0));
  }
  painter->restore();
}

void CMPassrate1::paintInE(QPainter *painter){
  int radis = inRadis;
  QRect rect(-radis,radis*2);
  painter->save();
  painter->setBrush(QBrush(QColor("#646464")));
  painter->setPen(Qt::NoPen);
  painter->drawEllipse(rect);
  painter->restore();
}

void CMPassrate1::paintTextE(QPainter *painter){
  int radis = 23;
  QRect rect(-radis,radis*2);
  painter->save();
  painter->setBrush(QBrush(QColor("#FFFFFF")));
  painter->setPen(Qt::NoPen);
  painter->drawEllipse(rect);
  painter->restore();
}

void CMPassrate1::paintPoint(QPainter *painter){
   painter->save();
   const QPoint points[3] = {
       QPoint(10,QPoint(-10,QPoint(0,inRadis-5)
     };
   int range = ((double)value/100)*360;
   painter->rotate(range);
   painter->setPen(Qt::NoPen);
   painter->setBrush(QBrush(QColor("#66CFFF")));
   painter->drawConvexPolygon(points,3);


   painter->restore();
}

void CMPassrate1::paintText(QPainter *painter){
  int radis = 23;
  QRect rect(-radis,radis*2);
  painter->save();
  painter->setBrush(QBrush(QColor("#000000")));
  painter->setPen(QPen(QColor("#000000")));
  QFont font = painter->font();
  font.setPixelSize(20);
  painter->setFont(font);
  painter->drawText(rect,Qt::AlignCenter,QString("%1%").arg(QString::number(value)));
  painter->restore();
}

void CMPassrate1::paintValue(QPainter *painter){
  int oRandis = outRadis-side;
  qDebug()<<"value::"<<value;
  int rangle = ((double)value/100)*360;
  QRectF rect(-oRandis,-oRandis,oRandis << 1,oRandis << 1);
  QPainterPath path;
  qDebug()<<"rangle:"<<rangle<<" start:"<<270-rangle;
  path.arcTo(rect,270-rangle,rangle);

  // QRectF(-120,-120,240,240)
  QPainterPath subPath;
  subPath.addEllipse(rect.adjusted((oRandis-inRadis),(oRandis-inRadis),-(oRandis-inRadis),-(oRandis-inRadis)));

  // path為扇形 subPath為橢圓
  path -= subPath;
  painter->save();
  painter->setBrush(valueColor);
  painter->setPen(Qt::NoPen);
  painter->drawPath(path);
  painter->restore();
}

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。