QT控件大全 三十二 QPotPlug

效果如图：

核心代码：

#ifndef QPOT1_H#define QPOT1_H#include <QtGui>#include <QtDesigner/QDesignerExportWidget>#include <math.h>#include <QWidget>class  QPot1 : public QWidget{    Q_OBJECT    Q_ENUMS(DisplayColor);    Q_PROPERTY(double minValue READ minValue WRITE setMinValue);    Q_PROPERTY(double maxValue READ maxValue WRITE setMaxValue);    Q_PROPERTY(int wheelStep READ wheelStep WRITE setWheelStep);    Q_PROPERTY(int fontDim READ fontDim WRITE setFontDim);    Q_PROPERTY(int numPrec READ numPrec WRITE setPrecision);    Q_PROPERTY(DisplayColor dispColor READ color WRITE setColor);    public:    QPot1(QWidget *parent = 0);    QSize minimumSizeHint() const;    QSize sizeHint() const;    enum DisplayColor    {        white, green, red, yellow, magenta, cyan    };    double actValue() const    {        return value;    }    double minValue() const    {        return min;    }    double maxValue() const    {        return max;    }    int wheelStep() const    {        return wheel;    }    int fontDim() const    {        return font;    }    int numPrec() const    {        return precision;    }    DisplayColor color() const    {        return dcolor;    }    signals:    void valueChanged(double);public slots:    void setMinValue(double);    void setMaxValue(double);    void setWheelStep(int);    void setFontDim(int);    void setPrecision(int);    void setColor(DisplayColor);    protected:    void paintEvent(QPaintEvent *);    void wheelEvent(QWheelEvent *);    void paintLevel();    void paintDial();    void paintBorder();    void paintValue();    void paintScale();private:    int spanAngle;    int startAngle;    int startPoint;    double arc;    double value;    double min;    double max;    int wheel;    int font;    int precision;    DisplayColor dcolor;   };#endif

#include "qpot1.h"#include <QWidget>QPot1::QPot1(QWidget *parent) : QWidget(parent){    spanAngle = 0;    startAngle = 225 * 16;    startPoint = 225 * 16;    min = 0;    max = 100;    value = 0;    arc = 0;    wheel = 1;    font = 20;    precision = 0;    dcolor = green;}void QPot1::paintEvent(QPaintEvent *){    paintBorder();    paintDial();    paintScale();    paintValue();    paintLevel();   }void QPot1::paintScale(){    QPainter painter(this);    painter.setWindow(-100, -100, 200, 250);    painter.setRenderHint(QPainter::Antialiasing);    painter.setPen(QPen(Qt::gray, 3, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    int nSteps1 = 6;    painter.save();    for (int i=0; i<=nSteps1; i++)    {        painter.drawLine(-45, 45, -40, 40);        painter.rotate(45);    }    painter.restore();    painter.setPen(QPen(Qt::gray, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    int nSteps2 = 18;    painter.save();    for (int i=0; i<=nSteps2; i++)    {        painter.drawLine(-42, 42, -40, 40);        painter.rotate(15);    }    painter.restore();}void QPot1::paintBorder(){    QPainter painter(this);    painter.setWindow(-100, -100, 200, 250);    painter.setRenderHint(QPainter::Antialiasing);    painter.setPen(QPen(Qt::black, 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    QLinearGradient linGrad1(-90, 15, -85, 15);    linGrad1.setColorAt(0, Qt::white);    linGrad1.setColorAt(1, QColor(80,80,80));    linGrad1.setSpread(QGradient::PadSpread);    painter.setBrush(linGrad1);    QRectF border(-90, -90, 180, 230);    painter.drawRect(border);        painter.setPen(QPen(Qt::gray, 1, Qt::DotLine, Qt::RoundCap, Qt::RoundJoin));    QRectF border1(-70, -70, 140, 130);    painter.drawRect(border1);    QRectF border2(-70, 70, 140, 60);    painter.drawRect(border2);    }void QPot1::paintDial(){    QPainter painter(this);    painter.setWindow(-100, -100, 200, 250);    painter.setRenderHint(QPainter::Antialiasing);    QLinearGradient linGrad(-48,0,96,0);    linGrad.setColorAt(0, Qt::gray);    linGrad.setColorAt(1, Qt::black);    linGrad.setSpread(QGradient::PadSpread);    painter.setBrush(linGrad);    painter.setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    painter.drawEllipse(-48,-48,96,96);    painter.setBrush(QBrush(Qt::black));    int nSteps = 35;    painter.save();    for (int i=0; i<=nSteps; i++)    {        painter.drawEllipse(0, 0, 35, 15 );        painter.rotate(10);    }    painter.restore();    QRadialGradient radGrad(-33,0,50);    radGrad.setColorAt(0, Qt::white);    radGrad.setColorAt(1, Qt::gray);    painter.setBrush(radGrad);    painter.setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    painter.drawEllipse(-33,-33,66,66);    painter.drawEllipse(-30,-30,60,60);}void QPot1::paintValue(){    QPainter painter(this);    painter.setWindow(-100, -100, 200, 250);    painter.setRenderHint(QPainter::Antialiasing);        QColor color;    switch (dcolor)    {    case white:        color=QColor(Qt::white);        break;    case green:        color=QColor(Qt::green);        break;    case red:        color=QColor(Qt::red);        break;    case yellow:        color=QColor(Qt::yellow);        break;    case magenta:        color=QColor(Qt::magenta);        break;    case cyan:        color=QColor(Qt::cyan);        break;    default:        color=QColor(Qt::green);        break;    }        painter.setPen(QPen(Qt::black, 1, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    painter.setBrush(Qt::black);    QRectF valRect(-50, 75, 100, 50);    painter.drawRect(valRect);       QLinearGradient linGrad1(-50,100,-45,100);    linGrad1.setColorAt(0, Qt::white);    linGrad1.setColorAt(1, Qt::black);    linGrad1.setSpread(QGradient::PadSpread);    painter.setBrush(linGrad1);    painter.setPen(QPen(Qt::black));    QRectF gradRect1(-50,75,100,50);    painter.drawRect(gradRect1);    QLinearGradient linGrad(0,75,0,150); linGrad.setColorAt(0, Qt::black);    linGrad.setColorAt(1, color);    linGrad.setSpread(QGradient::PadSpread);    painter.setBrush(linGrad);    painter.setOpacity(0.50);    QRectF gradRect(-50, 75, 100, 50);    painter.drawRect(gradRect);    value = min + (-arc)*(max-min)/4320;    QString actVal = QString("%1").arg(value,0,'f',precision);    QFont valFont("SanSerifArial", font, QFont::Bold);    painter.setFont(valFont);    painter.setOpacity(1);    painter.setPen(QPen(color));    painter.drawText(valRect, Qt::AlignCenter, actVal);        emit valueChanged(value);}void QPot1::paintLevel(){    QPainter painter(this);    painter.setWindow(-100, -100, 200, 250);    painter.setRenderHint(QPainter::Antialiasing);    painter.setPen(QPen(Qt::black, 7, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin));    painter.save();    painter.rotate(-arc/16);    painter.drawLine(-18, 18, 0, 0);    painter.restore();}void QPot1::setMinValue(double minValue){    min = minValue;    update();}void QPot1::setMaxValue(double maxValue){    max = maxValue;    update();}void QPot1::setWheelStep(int wheelStep){    wheel = wheelStep;    update();}void QPot1::setFontDim(int fontDim){    font = fontDim;    update();}void QPot1::setPrecision(int numPrec){    precision = numPrec;    update();}void QPot1::setColor(DisplayColor dispColor){    dcolor = dispColor;    update();}void QPot1::wheelEvent(QWheelEvent *e){    int delta = e->delta()/wheel;    arc = spanAngle-delta;    if (arc <= 0 && arc >= -270*16)    {        spanAngle = arc;        startPoint = startPoint-delta;        update();    }}QSize QPot1::minimumSizeHint() const{    return QSize(20, 25);}QSize QPot1::sizeHint() const{    return QSize(200, 250);}

源码工程：qq:609162385