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Qt+C++ custom control dashboard animation simulation

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Preface

This blog writes code for <<Qt+C++ Custom Control Dashboard Animation Simulation>>. The code is clean, regular and easy to read. Recommended for learning and application.

Article directory

1. Required tools and software

2. Usage steps

1. Import the library

2. Code implementation

3. Running results

3. Online assistance

1. Required tools and software

1. VS, Qt

2. C++

2. Usage steps

1. Import the library

#include <QWidget>
#include <QPropertyAnimation>
#include <QtMath>
#include <QPainter>

2. Code implementation

code show as below:

#include "GaugePanel.h"
GaugePanel::~GaugePanel()
{
    hShearAnimation->stop();
    vShearAnimation->stop();
    delete hShearAnimation;
    delete vShearAnimation;
}

void GaugePanel::paintEvent(QPaintEvent*)
{
    int width = this->width();
    int height = this->height();
    int side = qMin(width, height);

    //绘制准备工作,启用反锯齿,平移坐标轴中心,等比例缩放
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
    painter.translate(width / 2, height / 2);
    painter.scale(side / 215.0, side / 215.0);

    painter.shear(double(hShearValue / 100.0f), double(vShearValue / 100.0f));

    //内层渐变
    drawInnerGradient(&painter);

    //外层渐变
    drawOuterGradient(&painter);

    //外层光晕
    drawOuterHalo(&painter);

    //刻度线
    drawScale(&painter);

    //刻度值
    drawScaleNum(&painter);

    //绘制指针
    drawPointer(&painter);

    //绘制指针扇形
    drawPointerSector(&painter);

    //绘制值
    drawValue(&painter);

    //绘制单位
    drawUnit(&painter);
}

void GaugePanel::drawOuterGradient(QPainter* painter)
{
    if (radiusHalo <= radiusOuter)
        return;

    painter->save();

    QRectF rectangle(0 - radiusHalo, 0 - radiusHalo, radiusHalo * 2, radiusHalo * 2);
    QPen framePen(colorOuterFrame);
    framePen.setWidthF(1.5f);
    painter->setPen(framePen);
    painter->drawEllipse(rectangle);

    painter->setPen(Qt::NoPen);

    QPainterPath smallCircle;
    QPainterPath bigCircle;

    float radius = radiusOuter;
    smallCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);
    radius += (radiusHalo - radiusOuter);
    bigCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);

    //大圆抛去小圆部分
    QPainterPath gradientPath = bigCircle - smallCircle;
    QRadialGradient gradient(0, 0, radius, 0, 0);
    //gradient.setSpread(QGradient::ReflectSpread);

    gradient.setColorAt(0.85, colorOuterStart);
    gradient.setColorAt(0.98, colorOuterEnd);
    painter->setBrush(gradient);
    painter->drawPath(gradientPath);

    painter->restore();
}

void GaugePanel::drawInnerGradient(QPainter* painter)
{
    if (radiusOuter <= radiusInner)
        return;

    painter->save();
    painter->setPen(Qt::NoPen);

    QPainterPath smallCircle;
    QPainterPath bigCircle;

    float radius = radiusInner;
    smallCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);
    radius += (radiusOuter - radiusInner);
    bigCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);

    //大圆抛去小圆部分
    QPainterPath gradientPath = bigCircle - smallCircle;
    QRadialGradient gradient(0, 0, radius, 0, 0);
    //gradient.setSpread(QGradient::ReflectSpread);

    gradient.setColorAt(0.7, colorInnerStart);
    gradient.setColorAt(1, colorInnerEnd);
    painter->setBrush(gradient);
    painter->drawPath(gradientPath);

    painter->restore();
}

void GaugePanel::drawOuterHalo(QPainter* painter)
{
    painter->save();
    painter->setPen(Qt::NoPen);

    QPainterPath smallCircle;
    QPainterPath bigCircle;

    float radius = radiusHalo;
    smallCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);
    radius += (110.0 - radiusHalo);
    bigCircle.addEllipse(-radius, -radius, radius * 2, radius * 2);

    //大圆抛去小圆部分
    QPainterPath gradientPath = bigCircle - smallCircle;
    QRadialGradient gradient(0, 0, 100, 0, 0);
    gradient.setSpread(QGradient::ReflectSpread);

    gradient.setColorAt(radiusHalo / 100, colorHaloStart);
    gradient.setColorAt(1, colorHaloEnd);
    painter->setBrush(gradient);
    painter->drawPath(gradientPath);

    painter->restore();
}

void GaugePanel::drawScale(QPainter* painter)
{
    float radius = 85;
    painter->save();
    painter->setPen(QColor(255, 255, 255));

    painter->rotate(30);
    int steps = (30);
    double angleStep = (360.0 - 60) / steps;
    QPen pen = painter->pen();
    pen.setCapStyle(Qt::RoundCap);

    for (int i = 0; i <= steps; i++) {
        if (i % 3 == 0) {
            pen.setWidthF(1.5);
            painter->setPen(pen);
            QLineF line(0.0f, radius - 8.0f, 0.0f, radius);
            painter->drawLine(line);
        }
        else {
            pen.setWidthF(0.5);
            painter->setPen(pen);
            QLineF line(0.0f, radius - 3.0f, 0.0f, radius);
            painter->drawLine(line);
        }

        painter->rotate(angleStep);
    }

    painter->restore();
}

void GaugePanel::drawScaleNum(QPainter* painter)
{
    float radius = 95.0f;
    painter->save();
    painter->setPen(QColor(255, 255, 255));

    double startRad = (330 - 90) * (M_PI / 180);
    double deltaRad = (300) * (M_PI / 180) / 10;

    for (int i = 0; i <= 10; i++) {
        double sina = sin(startRad - i * deltaRad);
        double cosa = cos(startRad - i * deltaRad);
        double value = 1.0 * i * ((30) / 10);//刻度值范围

        QString strValue = QString("%1").arg((double)value, 0, 'f', 0);
        double textWidth = fontMetrics().width(strValue);
        double textHeight = fontMetrics().height();
        int x = radius * cosa - textWidth / 2;
        int y = -radius * sina + textHeight / 4;
        painter->drawText(x, y, strValue);
    }

    painter->restore();
}

void GaugePanel::drawPointer(QPainter* painter)
{
    painter->save();

    float radius = 83.0;
    painter->rotate(30 + int(value * 10));
    QPen pen = painter->pen();
    pen.setWidthF(1.0);
    pen.setColor(QColor(50, 154, 255, 200));
    painter->setPen(pen);
    QLineF line(0.0f, 0.0f, 0.0f, radius);
    painter->drawLine(line);

    painter->restore();
}

void GaugePanel::drawPointerSector(QPainter* painter)
{
    float radius = 87.5f;
    painter->save();
    painter->setPen(Qt::NoPen);

    QRectF rect(-radius, -radius, radius * 2, radius * 2);
    painter->setBrush(QColor(50, 154, 255, 50));
    painter->drawPie(rect, -120 * 16, -value * 16 * 10);

    painter->restore();
}

void GaugePanel::drawValue(QPainter* painter)
{
    int radius = 100;
    painter->save();
    painter->setPen(QColor(255, 255, 255));
    painter->setFont(QFont("Arial", 22, 22, true));

    QRectF textRect(-radius, -radius, radius * 2, radius * 2);
    QString strValue = QString("%1").arg((double)value, 0, 'f', 0);
    painter->drawText(textRect, Qt::AlignCenter, strValue);

    painter->restore();
}

void GaugePanel::drawUnit(QPainter* painter)
{
    int radius = 100;
    painter->save();
    painter->setPen(QColor(255, 255, 255));
    painter->setFont(QFont("Arial", 9, -1, true));

    QRectF textRect(-radius, -radius + 20, radius * 2, radius * 2);
    painter->drawText(textRect, Qt::AlignCenter, "km/h");

    painter->restore();
}

double GaugePanel::getValue() const
{
    return this->value;
}

int GaugePanel::getHShearValue() const
{
    return this->hShearValue;
}

int GaugePanel::getVShearValue() const
{
    return this->vShearValue;
}

double GaugePanel::getRadiusInner() const
{
    return radiusInner;
}

double GaugePanel::getRadiusOuter() const
{
    return radiusOuter;
}

double GaugePanel::getRadiusHalo() const
{
    return radiusHalo;
}

QColor GaugePanel::getColorOuterFrame() const
{
    return colorOuterFrame;
}

QColor GaugePanel::getColorInnerStart() const
{
    return colorInnerStart;
}

QColor GaugePanel::getColorInnerEnd() const
{
    return colorInnerEnd;
}

QColor GaugePanel::getColorOuterStart() const
{
    return colorOuterStart;
}

QColor GaugePanel::getColorOuterEnd() const
{
    return colorOuterEnd;
}

QColor GaugePanel::getColorHaloStart() const
{
    return colorHaloStart;
}

QColor GaugePanel::getColorHaloEnd() const
{
    return colorHaloEnd;
}

void GaugePanel::setValue(int value)
{
    setValue(double(value));
}

void GaugePanel::setValue(double value) {
    updateValue(value);
}

void GaugePanel::setHShearValue(int value)
{
    if (value > 100 || value < -100)
        return;

    this->hShearValue = value;
    update();
}

void GaugePanel::setVShearValue(int value)
{
    if (value > 100 || value < -100)
        return;

    this->vShearValue = value;
    update();
}

void GaugePanel::setColorOuterFrame(QColor color)
{
    colorOuterFrame = color;
}

void GaugePanel::setRadiusInner(int radius)
{
    setRadiusInner(double(radius));
}

void GaugePanel::setRadiusInner(double radius)
{
    if (radius >= 0.0f && radius < 100.0f) {
        radiusInner = radius;
        update();
    }
}

void GaugePanel::setRadiusOuter(int radius)
{
    setRadiusOuter(double(radius));
}

void GaugePanel::setRadiusOuter(double radius)
{
    if (radius > 0.0f && radius < 100.0f) {
        radiusOuter = radius;
        update();
    }
}

void GaugePanel::setRadiusHalo(int radius)
{
    setRadiusHalo(double(radius));
}

void GaugePanel::setRadiusHalo(double radius)
{
    if (radius > 0.0f && radius < 100.0f) {
        radiusHalo = radius;
        update();
    }
}

void GaugePanel::setColorInnerStart(QColor color)
{
    colorInnerStart = color;
}

void GaugePanel::setColorInnerEnd(QColor color)
{
    colorInnerEnd = color;
}

void GaugePanel::setColorOuterStart(QColor color)
{
    colorOuterStart = color;
}

void GaugePanel::setColorOuterEnd(QColor color)
{
    colorOuterEnd = color;
}

void GaugePanel::setColorHaloStart(QColor color)
{
    colorHaloStart = color;
}

void GaugePanel::setColorHaloEnd(QColor color)
{
    colorHaloEnd = color;
}

void GaugePanel::startShearAnimal(int duration, int hShearValue, int vShearValue)
{
    if (hShearValue == this->hShearValue && vShearValue == this->vShearValue) {
        return;
    }

    if (hShearAnimation->state() != QPropertyAnimation::Stopped) {
        hShearAnimation->stop();
    }

    if (vShearAnimation->state() != QPropertyAnimation::Stopped) {
        vShearAnimation->stop();
    }

    hShearAnimation->setDuration(duration);
    hShearAnimation->setStartValue(this->hShearValue);
    hShearAnimation->setEndValue(hShearValue);
    hShearAnimation->start();

    vShearAnimation->setDuration(duration);
    vShearAnimation->setStartValue(this->vShearValue);
    vShearAnimation->setEndValue(vShearValue);
    vShearAnimation->start();
}

void GaugePanel::updateValue(double value)
{
    if (value > 30.0 || value < 0.0) {
        return;
    }

    this->value = value;
    //update();
    this->update();
    // emit valueChanged(value);
}

3. Running results

3. Online assistance:

If you need to install the operating environment or remote debugging, please see your personal QQ business card at the bottom of the article for remote assistance from professional technicians!
1) Remote installation and running environment, code debugging
2) Qt, C++, Python entry guide
3) Interface beautification
4) Software production