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This article mainly introduces how to use Qt custom control to achieve circle loading progress bar, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian take you to understand.

Idea: draw an arc of 270 degrees, and then define a timer to rotate the coordinate system regularly to achieve the effect of rotation. The arc needs to use a gradient to achieve the effect of lighter and lighter color.

Key code: CMProcessBar1.cpp

CMProcessBar1::CMProcessBar1 (QWidget * parent): QWidget (parent), ui (new Ui::CMProcessBar1) {ui- > setupUi (this); QTimer * timer = new QTimer; connect (timer,QTimer::timeout,this,updaterRotation); / / timing rotation coordinate system timer- > start (3); / / timing 3 milliseconds} CMProcessBar1::~CMProcessBar1 () {delete ui;} void CMProcessBar1::updaterRotation () {/ / cycle 360 degree rotation coordinate system rotation++ If (rotation) {rotation = 0;} update ();} void CMProcessBar1::paintEvent (QPaintEvent * event) {/ / draw a gradual arc according to QPaintPath 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) QConicalGradient gra (QPoint (0jue 0), 0); gra.setColorAt (0Magnum QColor ("# 3BB6FE")); gra.setColorAt (1Magical QColor ("# FFFFFF")); QBrush brush (gra); int radis = 40; int sider = 5; QRect rect (- radis,-radis,radis*2,radis*2); QPainterPath path; path.arcTo (rect,0, 270); QPainterPath subPath; subPath.addEllipse (rect.adjusted (sider, sider,-sider,-sider)); path = path-subPath Painter.setBrush (brush); / / QColor ("# 66CFFF") painter.setPen (Qt::NoPen); painter.rotate (rotation); painter.drawPath (path) } Thank you for reading this article carefully. I hope the article "how to use Qt custom controls to achieve circle loading progress bar" shared by the editor will be helpful to you. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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