QT实现动态波形的实时显示_qt波形显示,qt显示波形资源-CSDN文库

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在本文中，我们将深入探讨如何使用QT框架来实现动态波形的实时显示。QT是一个流行的、跨平台的应用程序开发框架，特别适用于创建图形用户界面（GUI）。动态波形的实时显示是许多科学、工程和音频处理应用的核心部分，它允许用户直观地观察数据流的变化。我们需要设置一个QT项目，导入必要的库。在QT Creator中，创建一个新的QT项目，选择"QT Widgets Application"模板。在.pro文件中，确保包含`QT += widgets`和`QT += gui`，因为我们需要使用这些库来构建GUI和进行图形绘制。接着，我们要创建一个窗口类，继承自`QWidget`，并重写`paintEvent()`函数。在这个函数中，我们将实现波形的绘制。为了实时更新，我们需要一个定时器，每当定时器触发时，都会调用`repaint()`方法，重新绘制界面。 ```cpp #include <QWidget> #include <QPainter> #include <QTimer> class WaveformWidget : public QWidget { Q_OBJECT public: explicit WaveformData(QWidget *parent = nullptr); ~WaveformData(); protected: void paintEvent(QPaintEvent *) override; private: QTimer *timer; // 假设我们有用于存储波形数据的成员变量，如QVector<double> waveformData QVector<double> m_waveformData; private slots: void updateWaveform(); }; ``` 在`WaveformData`类中，我们初始化定时器并在`updateWaveform()`槽函数中模拟数据的变化。例如，我们可以随机生成新的数据点，或者从一个数据流中读取新的样本。然后，将这些数据点添加到`waveformData`数组，并调用`repaint()`。 ```cpp WaveformData::WaveformData(QWidget *parent) : QWidget(parent), timer(new QTimer(this)) { timer->setInterval(100); // 每100毫秒更新一次 connect(timer, &QTimer::timeout, this, &WaveformData::updateWaveform); timer->start(); } void WaveformData::updateWaveform() { // 更新波形数据，这里仅作示例，实际应用中可能需要从传感器或其他数据源获取新数据 double newDataPoint = qrand() % 100; // 生成0-100的随机值 m_waveformData.append(newDataPoint); // 防止数据量过大，可以设定一定的最大数据点数量 if (m_waveformData.size() > 1000) { m_waveformData.removeFirst(); } repaint(); // 触发重绘事件 } ``` 在`paintEvent()`中，我们将使用`QPainter`来绘制波形。我们需要设置适当的坐标系，使Y轴表示波形的高度，X轴表示时间。然后，遍历`waveformData`数组，绘制每个数据点的线段。注意，为了获得平滑的曲线效果，可以考虑使用抗锯齿（`painter.setRenderHint(QPainter::Antialiasing)`）。 ```cpp void WaveformData::paintEvent(QPaintEvent *) { QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); // 设置画布大小和坐标轴范围 int width = this->width(); int height = this->height(); double maxX = width - 10; double maxY = height - 10; double minY = 0; // 绘制背景和坐标轴 painter.fillRect(rect(), Qt::white); painter.drawLine(5, maxY, 5, minY); painter.drawLine(5, minY, maxX, minY); // 计算X轴步进 double xStep = (maxX / static_cast<double>(m_waveformData.size())); // 绘制波形 painter.setPen(Qt::blue); for (int i = 0; i < m_waveformData.size() - 1; ++i) { double x1 = i * xStep + 5; double y1 = (1.0 - m_waveformData[i] / 100.0) * maxY; double x2 = (i + 1) * xStep + 5; double y2 = (1.0 - m_waveformData[i + 1] / 100.0) * maxY; painter.drawLine(x1, y1, x2, y2); } } ``` 至此，我们已经创建了一个基本的动态波形显示界面。你可以根据实际需求调整波形的颜色、样式、坐标轴范围以及数据更新的频率。此外，还可以添加滚动条、缩放功能，以便更精细地查看特定区域的波形，或者使用鼠标事件来捕捉特定的数据点。 QT的强大之处在于其丰富的图形和用户交互功能，结合C++的灵活性，可以轻松实现复杂而高效的可视化应用。在实际项目中，你可能需要连接到硬件设备，实时接收数据，或者与其他模块进行通信，这时可以利用QT的信号和槽机制来实现。QT为实现动态波形的实时显示提供了强大的工具和支持。

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boxing.rar （20个子文件）

boxing

qcustomplot.h 146KB

boxing.pro 436B

Makefile.Debug 186KB

qcustomplot.cpp 832KB

boxing.pro.user 33KB

Makefile.Release 186KB

ui_mainwindow.h 3KB

main.cpp 183B

mainwindow.ui 1KB

debug

moc_mainwindow.cpp 3KB

moc_mainwindow.o 411KB

moc_qcustomplot.cpp 241KB

moc_qcustomplot.o 1.86MB

mainwindow.o 453KB

main.o 449KB

boxing.exe 5.48MB

qcustomplot.o 3.7MB

mainwindow.cpp 2KB

mainwindow.h 421B

Makefile 20KB

release

/*************************************************************************** ** ** ** QCustomPlot, an easy to use, modern plotting widget for Qt ** ** Copyright (C) 2011-2015 Emanuel Eichhammer ** ** ** ** This program is free software: you can redistribute it and/or modify ** ** it under the terms of the GNU General Public License as published by ** ** the Free Software Foundation, either version 3 of the License, or ** ** (at your option) any later version. ** ** ** ** This program is distributed in the hope that it will be useful, ** ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** ** GNU General Public License for more details. ** ** ** ** You should have received a copy of the GNU General Public License ** ** along with this program. If not, see http://www.gnu.org/licenses/. ** ** ** **************************************************************************** ** Author: Emanuel Eichhammer ** ** Website/Contact: http://www.qcustomplot.com/ ** ** Date: 22.12.15 ** ** Version: 1.3.2 ** ****************************************************************************/ #include "qcustomplot.h" //////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////// QCPPainter //////////////////////////////////////////////////////////////////////////////////////////////////// /*! \class QCPPainter \brief QPainter subclass used internally This QPainter subclass is used to provide some extended functionality e.g. for tweaking position consistency between antialiased and non-antialiased painting. Further it provides workarounds for QPainter quirks. \warning This class intentionally hides non-virtual functions of QPainter, e.g. setPen, save and restore. So while it is possible to pass a QCPPainter instance to a function that expects a QPainter pointer, some of the workarounds and tweaks will be unavailable to the function (because it will call the base class implementations of the functions actually hidden by QCPPainter). */ /*! Creates a new QCPPainter instance and sets default values */ QCPPainter::QCPPainter() : QPainter(), mModes(pmDefault), mIsAntialiasing(false) { // don't setRenderHint(QPainter::NonCosmeticDefautPen) here, because painter isn't active yet and // a call to begin() will follow } /*! Creates a new QCPPainter instance on the specified paint \a device and sets default values. Just like the analogous QPainter constructor, begins painting on \a device immediately. Like \ref begin, this method sets QPainter::NonCosmeticDefaultPen in Qt versions before Qt5. */ QCPPainter::QCPPainter(QPaintDevice *device) : QPainter(device), mModes(pmDefault), mIsAntialiasing(false) { #if QT_VERSION < QT_VERSION_CHECK(5, 0, 0) // before Qt5, default pens used to be cosmetic if NonCosmeticDefaultPen flag isn't set. So we set it to get consistency across Qt versions. if (isActive()) setRenderHint(QPainter::NonCosmeticDefaultPen); #endif } QCPPainter::~QCPPainter() { } /*! Sets the pen of the painter and applies certain fixes to it, depending on the mode of this QCPPainter. \note this function hides the non-virtual base class implementation. */ void QCPPainter::setPen(const QPen &pen) { QPainter::setPen(pen); if (mModes.testFlag(pmNonCosmetic)) makeNonCosmetic(); } /*! \overload Sets the pen (by color) of the painter and applies certain fixes to it, depending on the mode of this QCPPainter. \note this function hides the non-virtual base class implementation. */ void QCPPainter::setPen(const QColor &color) { QPainter::setPen(color); if (mModes.testFlag(pmNonCosmetic)) makeNonCosmetic(); } /*! \overload Sets the pen (by style) of the painter and applies certain fixes to it, depending on the mode of this QCPPainter. \note this function hides the non-virtual base class implementation. */ void QCPPainter::setPen(Qt::PenStyle penStyle) { QPainter::setPen(penStyle); if (mModes.testFlag(pmNonCosmetic)) makeNonCosmetic(); } /*! \overload Works around a Qt bug introduced with Qt 4.8 which makes drawing QLineF unpredictable when antialiasing is disabled. Thus when antialiasing is disabled, it rounds the \a line to integer coordinates and then passes it to the original drawLine. \note this function hides the non-virtual base class implementation. */ void QCPPainter::drawLine(const QLineF &line) { if (mIsAntialiasing || mModes.testFlag(pmVectorized)) QPainter::drawLine(line); else QPainter::drawLine(line.toLine()); } /*! Sets whether painting uses antialiasing or not. Use this method instead of using setRenderHint with QPainter::Antialiasing directly, as it allows QCPPainter to regain pixel exactness between antialiased and non-antialiased painting (Since Qt < 5.0 uses slightly different coordinate systems for AA/Non-AA painting). */ void QCPPainter::setAntialiasing(bool enabled) { setRenderHint(QPainter::Antialiasing, enabled); if (mIsAntialiasing != enabled) { mIsAntialiasing = enabled; if (!mModes.testFlag(pmVectorized)) // antialiasing half-pixel shift only needed for rasterized outputs { if (mIsAntialiasing) translate(0.5, 0.5); else translate(-0.5, -0.5); } } } /*! Sets the mode of the painter. This controls whether the painter shall adjust its fixes/workarounds optimized for certain output devices. */ void QCPPainter::setModes(QCPPainter::PainterModes modes) { mModes = modes; } /*! Sets the QPainter::NonCosmeticDefaultPen in Qt versions before Qt5 after beginning painting on \a device. This is necessary to get cosmetic pen consistency across Qt versions, because since Qt5, all pens are non-cosmetic by default, and in Qt4 this render hint must be set to get that behaviour. The Constructor \ref QCPPainter(QPaintDevice *device) which directly starts painting also sets the render hint as appropriate. \note this function hides the non-virtual base class implementation. */ bool QCPPainter::begin(QPaintDevice *device) { bool result = QPainter::begin(device); #if QT_VERSION < QT_VERSION_CHECK(5, 0, 0) // before Qt5, default pens used to be cosmetic if NonCosmeticDefaultPen flag isn't set. So we set it to get consistency across Qt versions. if (result) setRenderHint(QPainter::NonCosmeticDefaultPen); #endif return result; } /*! \overload Sets the mode of the painter. This controls whether the painter shall adjust its fixes/workarounds optimized for certain output devices. */ void QCPPainter::setMode(QCPPainter::PainterMode mode, bool enabled) { if (!enabled && mModes.testFlag(mode)) mModes &= ~mode; else if (enabled && !mModes.testFlag(mode)) mModes |= mode; } /*! Saves the painter (see QPainter::save). Since QCPPainter adds some new internal state to QPainter, the save/restore functions are reimplemented to also save/restore those members. \note this function hides the non-virtual base class implementation. \see restore */ void QCPPainter::save() { mAntialiasingStack.push(mIsAntialiasing); QPainter::save(); } /*! Restores the painter (see QPainter::restore). Since QCPPainter adds some new inte

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