Qt自定义控件实现多彩色仪表盘_C/C++

本文实例为大家分享了Qt实现多彩色仪表盘的具体代码，供大家参考，具体内容如下

Qt自定义控件4：多彩色仪表盘

先看效果图：

Qt自定义控件实现多彩色仪表盘

思路：外围三色的圆弧红：蓝：绿 = 1：2：1，总共占270度。刻度线是根据所在圆弧的颜色而画，刻度线的角度也是根据坐标系的旋转而画。刻度值是根据刻度线的角度得到所要画的刻度的左上角的坐标，然后构成一个矩形，根据矩形画出刻度值。指针是根据四个点的坐标直接画的四边形，再旋转坐标系实现指针旋转的效果。下方的文字直接得到坐标横纵坐标位置得到矩形画出value的值

关键代码：CMPassrate3.cpp

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									void CMPassrate3::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);

									  drawBG(&painter);

									  drawE(&painter);

									  drawLine(&painter);

									  drawText(&painter);

									  drawBootomText(&painter);

									  drawPoint(&painter);

									}

									void CMPassrate3::drawE(QPainter* painter){

									  painter->setPen(Qt::NoPen);

									  QRect rectOut(-outRadius,-outRadius,2*outRadius,2*outRadius);

									  QRect rectInn(-innRadius,-innRadius,2*innRadius,2*innRadius);

									  painter->save();

									  painter->setBrush(QColor("#04EEB2"));

									  QPainterPath path;

									  path.arcTo(rectOut,-45,270.0/4);

									  QPainterPath subPath;

									  subPath.addEllipse(rectInn);

									  path -= subPath;

									  painter->drawPath(path);

									  painter->restore();

									  painter->save();

									  QPainterPath bluePath;

									  QPainterPath blueSubPath;

									  painter->setBrush(QColor("#2DC5F6"));

									  bluePath.arcTo(rectOut,-45+(270.0/4),270.0/2);

									  blueSubPath.addEllipse(rectInn);

									  bluePath -= blueSubPath;

									  painter->drawPath(bluePath);

									  painter->restore();

									  painter->save();

									  QPainterPath redPath;

									  QPainterPath redSubPath;

									  painter->setBrush(QColor("#FA468C"));

									  redPath.arcTo(rectOut,-45+270.0*3/4,270.0/4);

									  redSubPath.addEllipse(rectInn);

									  redPath -= redSubPath;

									  painter->drawPath(redPath);

									  painter->restore();

									}

									void CMPassrate3::drawLine(QPainter* painter){

									  painter->save();

									  painter->rotate(135);

									  //270/8度一格

									  for(int i = 0;i<9;i++){

									    if(i<3){

									      painter->setPen(QColor("#FA468C"));

									    }else if(i<6){

									      painter->setPen(QColor("#2DC5F6"));

									    }else{

									      painter->setPen(QColor("#04EEB2"));

									    }

									    QLine line(QPoint(lineStart,0),QPoint(innRadius,0));

									    painter->drawLine(line);

									    painter->rotate(270.0/8);

									  }

									  painter->restore();

									}

									void CMPassrate3::drawPoint(QPainter* painter){

									  const QPoint point[4]{

									    QPoint(0,0),QPoint(0,6),QPoint((lineStart-3)*qCos(135*3.14/180),(lineStart-3)*qSin(135*3.14/180)),QPoint(-6,0)

									  };

									  float range = 270.0/100*value;

									  painter->save();

									  painter->setBrush(QColor("#C2E481"));

									  painter->rotate(range);

									  painter->drawConvexPolygon(point,4);

									  painter->restore();

									}

									void CMPassrate3::drawBG(QPainter* painter){//可以自行添加背景图片实现更加精美的效果

									//  painter->save();

									//  QImage image(":/image/images/bg1.jpg");

									//  QRect rect(-this->width(),-this->height(),this->width()*2,this->height()*2);

									//  painter->drawImage(rect,image);

									//  painter->restore();

									}

									void CMPassrate3::drawText(QPainter *painter){

									  painter->save();

									  //初始为

									  painter->setPen(Qt::black);

									  QFont font = painter->font();

									  font.setPixelSize(8);

									  painter->setFont(font);

									  float x,y;

									  for(float i =0;i<=100;i+=12.5){

									    x = lineStart*qCos((135+(270.0/8)*((i+1)/12.5))*3.14/180);

									    y = lineStart*qSin((135+(270.0/8)*((i+1)/12.5))*3.14/180);

									    QRect rect;

									    if(i<50){

									      rect.setX(x);

									      rect.setY(y);

									    }else if(i>50){

									      rect.setX(x-17);

									      rect.setY(y-7);

									    }else{

									      rect.setX(x);

									      rect.setY(y);

									    }

									    rect.setWidth(17);

									    rect.setHeight(10);

									    painter->drawText(rect,Qt::AlignCenter,QString::number(i));

									  }

									  painter->restore();

									}

									void CMPassrate3::drawBootomText(QPainter *painter){

									  painter->save();

									  painter->setPen(Qt::black);

									  QFont font = painter->font();

									  font.setPixelSize(25);

									  painter->setFont(font);

									  painter->translate(0,outRadius-12);

									  int length = 20;

									  QRect rect(-length,-length,length*2,length*2);

									  painter->drawText(rect,Qt::AlignCenter,QString::number(value));

									  painter->restore();

									}