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Xiaobian to share with you how to use Qt custom controls to achieve multi-color dashboard, I believe most people still do not know how to share this article for your reference, I hope you have a lot of harvest after reading this article, let's go to understand it together!

specific contents are as follows

Qt Custom Controls 4: Multi-Color Dashboard

Idea: The arc of the outer three colors red: blue: green = 1:2:1, accounting for a total of 270 degrees. Graduation marks are drawn according to the color of the arc, and the angle of the graduation marks is also drawn according to the rotation of the coordinate system. The scale value is the coordinate of the upper left corner of the scale to be drawn according to the angle of the scale line, and then a rectangle is formed, and the scale value is drawn according to the rectangle. The pointer is a quadrilateral drawn directly according to the coordinates of four points, and then rotates the coordinate system to achieve the effect of pointer rotation. The text below directly gets the coordinates, the ordinate position, the rectangle, and the value.

Key Code: CMPassrate3.cpp

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 degrees for(int i = 0;isetPen(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){//You can add background image to achieve more beautiful effect// 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(); //initially painter->setPen (Qt::black); QFont font = painter->font(); font.setPixelSize(8); painter->setFont(font); float x,y; for (float i =0;idrawText(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();} The above is "How to use Qt custom controls to achieve multi-color dashboard" All the content of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!

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