Qt自定义控件实现圆盘进度条

来源：本站原创|时间：2020-01-10|栏目：C语言|点击：次

本文实例为大家分享了Qt圆盘进度条的具体代码，供大家参考，具体内容如下

自定义控件二：圆盘进度条

上效果图：

主要思路：使用qpainter根据图形需求画圆和圆弧，画指针（多边形，指定坐标即可），根据具体的value值旋转坐标系，使指针达到旋转效果，旋转度数是根据value值，总共360度，占比求得。最中间需要画文字上去，每次更新value时调用update（）方法，重绘界面。

主要代码：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);

  //绘制外圆
  paintSide(&painter);
  paintOutE(&painter);
  
  paintLine(&painter);//绘制刻度线
  paintInE(&painter);
  paintPoint(&painter);//绘制指针
  paintTextE(&painter);//绘制文字所在的圆
  paintText(&painter);//绘制文字
  paintValue(&painter);//绘制value对应的填充角度
}

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,radis*2,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,radis*2,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,radis*2,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(10,0),
       QPoint(-10,0),
       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,radis*2,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为扇形 subPath为椭圆
  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内容，希望对大家的学习有所帮助，也希望大家多多支持我们。

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