QT--源码实现烧烤箱表盘实现

//自定义画笔、绘制窗口、表盘绘制和渐近线操作

具体效果如下：间隔一秒自动旋转

/*------------头函数----------------*/

#ifndef OVENTIMER_H

#define OVENTIMER_H

#include <QDateTime>

#include <QtWidgets/QWidget>

#include <QTimer>

class OvenTimer : public QWidget

    Q_OBJECT

public:

    OvenTimer(QWidget *parent = 0);

    void setDuration(int secs);

    int duration() const;

    void draw(QPainter *painter);

signals:

    void timeout();

protected:

    void paintEvent(QPaintEvent *event);

    void mousePressEvent(QMouseEvent *event);

private:

    QDateTime finishTime;

    QTimer *updateTimer;

    QTimer *finishTimer;

};

#endif

/*------------原函数----------------*/

#include <QtGui>

#include <cmath>

#include<Qdebug>

#ifndef M_PI

#define M_PI 3.14159265359

#endif

#include "oventimer.h"

const double DegreesPerMinute = 7.0;

const double DegreesPerSecond = DegreesPerMinute / 60;

const int MaxMinutes = 45;

const int MaxSeconds = MaxMinutes * 60;

const int UpdateInterval = 1;

OvenTimer::OvenTimer(QWidget *parent)

    : QWidget(parent)

    finishTime = QDateTime::currentDateTime();

    updateTimer = new QTimer(this);

    connect(updateTimer, SIGNAL(timeout()), this, SLOT(update()));

    finishTimer = new QTimer(this);

    finishTimer->setSingleShot(true);

    connect(finishTimer, SIGNAL(timeout()), this, SIGNAL(timeout()));

    connect(finishTimer, SIGNAL(timeout()), updateTimer, SLOT(stop()));

    QFont font;

    font.setPointSize(8);

    setFont(font);

void OvenTimer::setDuration(int secs)

    secs = qBound(0, secs, MaxSeconds);

    finishTime = QDateTime::currentDateTime().addSecs(secs);

    if (secs > 0) {//设置几秒更新一次

        updateTimer->start(UpdateInterval * 1000);

        finishTimer->start(secs * 1000);

    } else {

        updateTimer->stop();

        finishTimer->stop();

    update();

int OvenTimer::duration() const

    int secs = QDateTime::currentDateTime().secsTo(finishTime);

    if (secs < 0)

        secs = 0;

    return secs;

void OvenTimer::mousePressEvent(QMouseEvent *event)

    QPointF point = event->pos() - rect().center();

    double theta = std::atan2(-point.x(), -point.y()) * 180.0 / M_PI;

    setDuration(duration() + int(theta / DegreesPerSecond));

    update();

//每次的图形窗口改变都会调用此重新绘制函数

void OvenTimer::paintEvent(QPaintEvent * /* event */)

    QPainter painter(this);

    //设置反走样设置，减少边界的虚化

    painter.setRenderHint(QPainter::Antialiasing, true);

    int side = qMin(width(), height());

    qDebug() <<pos()<<endl;

    qDebug() <<width()<<endl;

    qDebug() <<height()<<endl;

//第一个参数用来显示画笔显示图形在窗口上的偏移

    painter.setViewport((width() - side) / 2, (height() - side) / 2,

                        side, side);

    //偏移中间这样就可以显示整个图形

    painter.setWindow(-50, -50, 100, 100);

    draw(&painter);

void OvenTimer::draw(QPainter *painter)

    static const int triangle[3][2] = {

        { -2, -49 }, { +2, -49 }, { 0, -47 }

};

    QPen thickPen(palette().foreground(), 1.5);

    QPen thinPen(palette().foreground(), 0.5);

    QColor niceBlue(150, 150, 200);

    painter->setPen(thinPen);

    painter->setBrush(palette().foreground());

    //最上面的三角形 第一个画几个点，点的位置

    painter->drawPolygon(QPolygon(3, &triangle[0][0]));

    //设置背景渐变

    QConicalGradient coneGradient(0, 0, -90.0);

    coneGradient.setColorAt(0.0, Qt::darkGray);

    coneGradient.setColorAt(0.2, niceBlue);

    coneGradient.setColorAt(0.5, Qt::white);

    coneGradient.setColorAt(1.0, Qt::darkGray);

    painter->setBrush(coneGradient);

    painter->drawEllipse(-46, -46, 92, 92);

//四周变化组合

    QRadialGradient haloGradient(0, 0, 20, 0, 0);

    haloGradient.setColorAt(0.0, Qt::lightGray);

    haloGradient.setColorAt(0.8, Qt::darkGray);

    haloGradient.setColorAt(0.9, Qt::white);

    haloGradient.setColorAt(1.0, Qt::black);

    painter->setPen(Qt::NoPen);

    painter->setBrush(haloGradient);

    painter->drawEllipse(-20, -20, 40, 40);

//线性渐变具体参见博客：https://mp.csdn.net/postedit/80782701

    QLinearGradient knobGradient(-7, -25, 7, -25);

    knobGradient.setColorAt(0.0, Qt::black);

    knobGradient.setColorAt(0.2, niceBlue);

    knobGradient.setColorAt(0.3, Qt::lightGray);

    knobGradient.setColorAt(0.8, Qt::white);

    knobGradient.setColorAt(1.0, Qt::black);

    //painter自带的坐标系旋转类 返回60s  1°

    painter->rotate(duration() * DegreesPerSecond);

    //同样渐变线也要跟着动

    painter->setBrush(knobGradient);

    painter->setPen(thinPen);

    painter->drawRoundRect(-7, -25, 14, 50, 99, 49);

    for (int i = 0; i <= MaxMinutes; ++i) {

        if (i % 5 == 0) { //当为特殊时刻变粗

            //画圆盘

            painter->setPen(thickPen);

            painter->drawLine(0, -41, 0, -44);

            painter->drawText(-15, -41, 30

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