Qt自定义控件实现仪表盘 Qt自定义控件实现仪表盘

1.预览图
2. 代码

头文件
源文件

3. 用法

1.预览图

文章图片

2. 代码 【Qt自定义控件实现仪表盘】
头文件

#ifndef MOTORMETER_H#define MOTORMETER_H#include #include #include #include #include #include #include #include class motormeter : public QWidget{Q_OBJECTpublic:explicit motormeter(QWidget *parent = nullptr); ~motormeter(); protected:void paintEvent(QPaintEvent*); private:int degRotate =-120; private:void DrawPoint(QPainter&,int); void DrawDigital(QPainter&,int); void DrawCircle(QPainter&,int); void DrawSmallScale(QPainter&,int); void DrawBigScale(QPainter&,int); void DrawText(QPainter&,int); void DrawPointer(QPainter&,int); void drawIndicator(QPainter *painter); public slots:void valueChanged(int); }; #endif // MOTORMETER_H

源文件

#include "motormeter.h"motormeter::motormeter(QWidget *parent) : QWidget(parent){}motormeter::~motormeter(){}void motormeter::paintEvent(QPaintEvent*){QPainter painter(this); int width=this->width(); int height=this->height(); int radius=((width>height)?height:width)/2; //移动画笔到中下方painter.translate(width/2,height*0.6); //启用反锯齿painter.setRenderHint(QPainter::Antialiasing, true); painter.setPen(Qt::NoPen); //设置画刷颜色painter.setBrush(QColor(138,43,226)); DrawPoint(painter,radius); DrawDigital(painter,radius-10); DrawCircle(painter,radius-35); DrawSmallScale(painter,radius-60); DrawBigScale(painter,radius-75); DrawText(painter,radius/2); DrawPointer(painter,radius-100); }//绘制外圈点void motormeter::DrawPoint(QPainter& painter,int radius){//组装点的路径图QPainterPath pointPath; pointPath.moveTo(-2,-2); pointPath.lineTo(2,-2); pointPath.lineTo(2,2); pointPath.lineTo(0,4); pointPath.lineTo(-2,2); //绘制13个小点for(int i=0; i<13; ++i){QPointF point(0,0); painter.save(); painter.setBrush(QColor(255,127,80)); //计算并移动绘图对象中心点point.setX(radius*qCos(((210-i*20)*M_PI)/180)); point.setY(radius*qSin(((210-i*20)*M_PI)/180)); //计算并移动绘图对象的中心点painter.translate(point.x(),-point.y()); //计算并选择绘图对象坐标painter.rotate(-120+i*20); //绘制路径painter.drawPath(pointPath); painter.restore(); }}//绘制外圈数字，原理和绘制圆圈点一样void motormeter::DrawDigital(QPainter& painter,int radius){//设置画笔，画笔默认NOPENpainter.setPen(QColor(218,112,214)); QFont font; font.setFamily("Cambria"); font.setPointSize(15); painter.setFont(font); for(int i=0; i<13; ++i){QPointF point(0,0); painter.save(); point.setX(radius*qCos(((210-i*20)*M_PI)/180)); point.setY(radius*qSin(((210-i*20)*M_PI)/180)); painter.translate(point.x(),-point.y()); painter.rotate(-120+i*20); painter.drawText(-15, -5, 40, 30,Qt::AlignCenter,QString::number(i*20)); painter.restore(); }//还原画笔painter.setPen(Qt::NoPen); }//绘制外圈void motormeter::DrawCircle(QPainter& painter,int radius){//保存绘图对象painter.save(); //计算大小圆路径QPainterPath outRing; QPainterPath inRing; outRing.moveTo(0,0); inRing.moveTo(0,0); outRing.arcTo(-radius,-radius, 2*radius,2*radius,-31,242); inRing.addEllipse(-radius+20,-radius+20,2*(radius-20),2*(radius-20)); outRing.closeSubpath(); //设置渐变色kQRadialGradient radialGradient(0,0,radius,0,0); radialGradient.setColorAt(0.93,QColor(138,43,226)); radialGradient.setColorAt(1,QColor(0,0,0)); //设置画刷painter.setBrush(radialGradient); //大圆减小圆painter.drawPath(outRing.subtracted(inRing)); //painter.drawPath(outRing); //painter.drawPath(inRing); painter.restore(); }//绘制刻度void motormeter::DrawSmallScale(QPainter& painter,int radius){//组装点的路径图QPainterPath pointPath; pointPath.moveTo(-2,-2); pointPath.lineTo(-1,-4); pointPath.lineTo(1,-4); pointPath.lineTo(2,-2); pointPath.lineTo(1,8); pointPath.lineTo(-1,8); //绘制121个小点for(int i=0; i<121; ++i){QPointF point(0,0); painter.save(); point.setX(radius*qCos(((210-i*2)*M_PI)/180)); point.setY(radius*qSin(((210-i*2)*M_PI)/180)); painter.translate(point.x(),-point.y()); painter.rotate(-120+i*2); if(i>=90) painter.setBrush(QColor(250,0,0)); painter.drawPath(pointPath); painter.restore(); }}//绘制刻度void motormeter::DrawBigScale(QPainter& painter,int radius){//组装点的路径图QPainterPath pointPath1; pointPath1.moveTo(-2,-2); pointPath1.lineTo(-1,-4); pointPath1.lineTo(1,-4); pointPath1.lineTo(2,-2); pointPath1.lineTo(1,8); pointPath1.lineTo(-1,8); QPainterPath pointPath2; pointPath2.moveTo(-2,-2); pointPath2.lineTo(-1,-4); pointPath2.lineTo(1,-4); pointPath2.lineTo(2,-2); pointPath2.lineTo(1,15); pointPath2.lineTo(-1,15); //绘制25个刻度for(int i=0; i<25; ++i){QPointF point(0,0); painter.save(); point.setX(radius*qCos(((210-i*10)*M_PI)/180)); point.setY(radius*qSin(((210-i*10)*M_PI)/180)); painter.translate(point.x(),-point.y()); painter.rotate(-120+i*10); if(i>=18) painter.setBrush(QColor(250,0,0)); if(i%2){painter.drawPath(pointPath1); }else{painter.drawPath(pointPath2); }painter.restore(); }}//绘制中心文字km/hvoid motormeter::DrawText(QPainter& painter,int radius){painter.save(); painter.setPen(QColor(153,51,250)); QFont font; font.setFamily("Cambria"); font.setPointSize(16); painter.setFont(font); painter.drawText(-25, -radius, 60, 30,Qt::AlignCenter,QString("km/h")); painter.restore(); }//绘制指针void motormeter::DrawPointer(QPainter& painter,int radius){//组装点的路径图QPainterPath pointPath; pointPath.moveTo(10,0); pointPath.lineTo(1,-radius); pointPath.lineTo(-1,-radius); pointPath.lineTo(-10,0); pointPath.arcTo(-10,0,20,20,180,180); QPainterPath inRing; inRing.addEllipse(-5,-5,10,10); painter.save(); QRadialGradient radialGradient(0,0,radius,0,0); radialGradient.setColorAt(0,QColor(0,199,140,150)); radialGradient.setColorAt(1,QColor(255,153,18,150)); //计算并选择绘图对象坐标painter.rotate(degRotate); painter.setBrush(radialGradient); painter.drawPath(pointPath.subtracted(inRing)); painter.restore(); }void motormeter::valueChanged(int value){this->degRotate = value; update(); }

3. 用法创建类，然后在创建的头文件和源文件里面添加上述代码