C++ QT 自绘表盘

效果图

代码

• 代码没什么好说的，直接上源码
• .h

#pragma once#include <QWidget>
#include <QPainter>
#include <QResizeEvent>
#include <QtMath>
#include <QCoreApplication>class DialPlateWidget : public QWidget
{Q_OBJECTQ_PROPERTY(double minValue READ getMinValue WRITE setMinValue USER true)Q_PROPERTY(double maxValue READ getMaxValue WRITE setMaxValue USER true)Q_PROPERTY(double value READ getValue WRITE setValue USER true)public:explicit DialPlateWidget(QWidget *parent = nullptr);// 获取和设置最小值double getMinValue() const;void setMinValue(double minValue);// 获取和设置最大值double getMaxValue() const;void setMaxValue(double maxValue);/// @brief  设置当前值void setValue(double ivalue);double getValue() const;/// @brief 设置标题和单位/// @param title/// @param unitvoid setContent(QString title, QString unit = QString());QSize sizeHint() const override;QSize minimumSizeHint() const override;~DialPlateWidget();private:void paintEvent(QPaintEvent *event) override;void drawBg(QPainter *painter);void drawDial(QPainter *painter);void drawScaleNum(QPainter *painter);void drawIndicator(QPainter *painter);void drawText(QPainter *painter);private:QString unit;            // 单位QString title;           // 名称const static int radius; // 半径double maxv;             // 最小值double minv;             // 最大值double percent = 0;      // 百分比int m_refSize = 200;     // 刻度线长度int Angle = 45;          // 刻度线角度double m_value = 0;      // 当前值
};

• cpp

#include "dialPlateWidget.h"const int DialPlateWidget::radius = 100;DialPlateWidget::DialPlateWidget(QWidget *parent) : QWidget(parent)
{maxv = 200;minv = 0;this->installEventFilter(this);m_refSize = 2.5 * radius;
}DialPlateWidget::~DialPlateWidget()
{
}void DialPlateWidget::setValue(double ivalue)
{// 确保值在最小值和最大值之间if (ivalue < minv){ivalue = minv;}else if (ivalue > maxv){ivalue = maxv;}m_value = ivalue;percent = (ivalue - minv) / (maxv - minv) * 100;update();
}double DialPlateWidget::getValue() const
{return minv + percent * (maxv - minv) / 100; // 根据百分比计算实际值
}QSize DialPlateWidget::sizeHint() const
{return QSize(m_refSize, m_refSize);
}QSize DialPlateWidget::minimumSizeHint() const
{return QSize(30, 10);
}void DialPlateWidget::paintEvent(QPaintEvent *event)
{QPainter painter(this);painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);// 计算缩放比例，确保仪表盘适应Widget大小float scale = qMin(width(), height()) / (float)m_refSize;painter.scale(scale, scale);// 设置坐标原点为中心点painter.translate(width() / (2 * scale), height() / (2 * scale));// 绘制背景、刻度线、刻度数字、指针和文字drawBg(&painter);drawDial(&painter);drawScaleNum(&painter);drawIndicator(&painter);drawText(&painter);QWidget::paintEvent(event);
}void DialPlateWidget::drawBg(QPainter *painter)
{int r = radius;painter->save();painter->setPen(Qt::NoPen);painter->setBrush(QColor(172, 172, 172));painter->drawEllipse(-r, -r, r * 2, r * 2);r = radius * 0.9;painter->setBrush(QColor(40, 40, 40));painter->setPen(Qt::NoPen);painter->drawEllipse(-r, -r, r * 2, r * 2);painter->restore();
}void DialPlateWidget::drawDial(QPainter *painter)
{int r = radius * 0.85;double lineWidth = 1;painter->save();painter->rotate(Angle);double rotate = (double)(360 - (Angle * 2)) / 100;for (int i = 0; i <= 100; i++){QColor color = QColor(84, 84, 84);if (i <= 30)color = QColor(250, 0, 0);if (i > 30)color = QColor(0, 255, 0, 255);if ((i % 10) == 0){painter->setPen(QPen(color, 4.2 * lineWidth));painter->drawLine(0, r, 0, r / 1.2);}else if ((i % 2) == 0){painter->setPen(QPen(color, 1 * lineWidth));painter->drawLine(0, r, 0, r / 1.1);}painter->rotate(rotate);}painter->restore();
}void DialPlateWidget::drawScaleNum(QPainter *painter)
{painter->save();int r = (int)(radius * 0.6); // 增加半径，使刻度数字更远离中心painter->setFont(QFont("Arial", 12));painter->setPen(QPen(QColor(255, 255, 255)));QFontMetricsF fm = QFontMetricsF(painter->font());// 计算五个标值的间隔double valueRange = maxv - minv;double valueStep = valueRange / 4.0;          // 四个间隔，五个标值double angleStep = (360.0 - Angle * 2) / 4.0; // 对应的角度间隔for (int i = 0; i <= 4; ++i){double value = minv + i * valueStep;       // 当前标值double angle = 90 + Angle + i * angleStep; // 当前标值对应的角度float angleArc = (int(angle) % 360) * 3.14 / 180; // 转换为弧度int x = r * cos(angleArc);int y = r * sin(angleArc);QString speed = QString::number(value);int w = (int)fm.width(speed);int h = (int)fm.height();x = x - w / 2;y = y + h / 4; // 调整文本位置painter->drawText(QPointF(x, y), speed);}painter->restore();
}void DialPlateWidget::drawIndicator(QPainter *painter)
{painter->save();QPolygon pts;int r = radius * 0.6;pts.setPoints(3, -2, 0, 2, 0, 0, r);double angle = Angle + (360.0 - 2 * Angle) * (percent / 100.0);painter->rotate(angle);// 绘制指针QRadialGradient haloGradient(0, 0, 60, 0, 0); // 辐射渐变，内部填充颜色haloGradient.setColorAt(0, QColor(100, 100, 100));haloGradient.setColorAt(1, QColor(250, 50, 50)); // redpainter->setPen(QColor(250, 150, 150));          // 边框颜色painter->setBrush(haloGradient);painter->drawConvexPolygon(pts);// 绘制中心圆圈QRadialGradient radial(0, 0, 14); // 渐变radial.setColorAt(0.0, QColor(100, 100, 100));radial.setColorAt(1.0, QColor(250, 50, 50));painter->setPen(Qt::NoPen); // 填满没有边界painter->setBrush(radial);painter->drawEllipse(-7, -7, 14, 14);painter->restore();
}void DialPlateWidget::drawText(QPainter *painter)
{painter->save();painter->setFont(QFont("Arial", 8));painter->setPen(QPen(QColor(255, 255, 255)));QFontMetricsF fm = QFontMetricsF(painter->font());QString speed = title + QString::number(m_value) + unit;int w = (int)fm.width(speed);painter->drawText(QPointF(-w / 2, (int)(0.7 * radius)), speed);painter->restore();
}void DialPlateWidget::setContent(QString title, QString unit)
{this->unit = unit;this->title = title;update(); // 更新显示
}double DialPlateWidget::getMinValue() const
{return minv;
}void DialPlateWidget::setMinValue(double minValue)
{minv = minValue;
}double DialPlateWidget::getMaxValue() const
{return maxv;
}void DialPlateWidget::setMaxValue(double maxValue)
{maxv = maxValue;
}