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Qt无边框窗口拖拽和阴影

news 2026/2/11 0:39:36

先看下效果：

在这里插入图片描述

说明

自定义窗口控件的无边框,窗口事件由于没有系统自带边框,无法实现拖拽拉伸等事件的处理,一种方法就是重新重写主窗口的鼠标事件，一种时通过nativeEvent事件处理。重写事件相对繁琐,我们这里推荐nativeEvent处理。注意后续我们在做win平台的进程通信，也会用到它！

我们这里使用的是：nativeEvent

软件用到的样式表，这里就不展示了，大家可以自行调整！

关键点说明

QPainterPath

QPainterPath类提供一个容器，可以用来创建图形并且重复使用。绘制器路径是由许多图形构建基块（如矩形、椭圆形、直线和曲线）组成的对象。构建基块可以连接在封闭的子路径中，例如作为矩形或椭圆。封闭路径具有重合的起点和终点。或者它们可以作为未闭合的子路径独立存在，例如直线和曲线。

抗锯齿

抗锯齿是一种常见的图形处理技术，用于减少在显示器上呈现的图像中出现的锯齿状边缘。
抗锯齿技术通过在边缘周围添加额外的像素来平滑边缘，从而减少锯齿状边缘。这种技术基于亚像素级别的渲染，它将颜色逐渐混合到边缘像素的周围像素中，使得边缘更加平滑。
打开抗锯齿可以使图像更加平滑，尤其是在呈现锐利直线或曲线时。这种技术可以减少锯齿状边缘，使得图像更加清晰，更加真实。特别是在高分辨率屏幕上，抗锯齿可以使得字体更加易读，图像更加细腻。
虽然抗锯齿可以使图像更加平滑，但在某些情况下，关闭抗锯齿可能更加合适。关闭抗锯齿可以提高图像处理速度。
这里我们基于Qt绘图框架用的是：

setRenderHint(QPainter::Antialiasing, true); //打开抗锯齿
setRenderHint(QPainter::Antialiasing, false); //关闭抗锯齿

具体实现

CDlgComBase,无边框窗口,带阴影，支持拖拽，注意:

该实现方案不支持存在多个显示屏的情况！
该实现方案仅支持win平台！

实现无边框带阴影的窗口代码，下面的代码供大家参考：

DlgComBase.h

#pragma once
#include "DlgShadow.h"
#include "FrameComTitleBar.h"
#include <QVBoxLayout>class CDlgComBase : public CDlgShadow
{Q_OBJECTpublic:CDlgComBase(QWidget *parent = 0, bool bCenterDlg = true, bool bHasTitleBar = true);~CDlgComBase();void SetWindowsTitle(const QString& strTitle, bool bCheckPos = false);// 显示隐藏按钮void ShowMinBtn(bool bShow);void ShowMaxBtn(bool bShow);void ShowCloseBtn(bool bShow);void ShowSettingBtn(bool bShow);void ShowMaximized();void SetTitleBarObjectName(QString strObjectName);void SetHeadBarHeight(int nHeight);protected:virtual bool IsCaption(int nXPos, int nYPos);QWidget* GetCenterWidget() { return &m_frameCenter; }virtual void OnNcLBtnDbClick(int nXPos, int nYPos);protected slots:void OnTimerCenter();private:CFrameComTitleBar		m_frameComTitleBar;QVBoxLayout				m_vBoxLayout;QFrame					m_frameCenter;bool					m_bHasTitleBar;
};

DlgComBase.cpp

#include "DlgComBase.h"
#include <QTimer>CDlgComBase::CDlgComBase(QWidget *parent, bool bCenterDlg, bool bHasTitleBar)
: CDlgShadow(parent), m_frameComTitleBar(this), m_frameCenter(this), m_bHasTitleBar(bHasTitleBar)
{m_frameComTitleBar.setObjectName("framComTitleBar");m_frameComTitleBar.setFixedHeight(GetHeadBarHeight());int nShadowLen = GetShadowLen();m_vBoxLayout.setContentsMargins(nShadowLen, nShadowLen, nShadowLen, nShadowLen);m_vBoxLayout.setSpacing(0);if (m_bHasTitleBar){m_vBoxLayout.addWidget(&m_frameComTitleBar);}m_vBoxLayout.addWidget(&m_frameCenter);m_frameCenter.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);setLayout(&m_vBoxLayout);if (bCenterDlg)QTimer::singleShot(10, this, SLOT(OnTimerCenter()));
}CDlgComBase::~CDlgComBase()
{}void CDlgComBase::SetWindowsTitle(const QString& strTitle, bool bCheckPos)
{m_strTitle = strTitle;m_frameComTitleBar.SetWindowsTitle(strTitle, bCheckPos);setWindowTitle(strTitle);
}void CDlgComBase::ShowMinBtn(bool bShow)
{m_frameComTitleBar.ShowMinBtn(bShow);
}void CDlgComBase::ShowMaxBtn(bool bShow)
{SetHasMaxFun(bShow);m_frameComTitleBar.ShowMaxBtn(bShow);
}void CDlgComBase::ShowCloseBtn(bool bShow)
{m_frameComTitleBar.ShowCloseBtn(bShow);
}void CDlgComBase::ShowSettingBtn(bool bShow)
{m_frameComTitleBar.ShowSettingBtn(bShow);
}bool CDlgComBase::IsCaption(int nXPos, int nYPos)
{QWidget* pChild = childAt(nXPos, nYPos);if (pChild == NULL){ADD_LOGD("CDlgComBase::IsCaption() return true");return true;}if (pChild == &m_frameComTitleBar || pChild == m_frameComTitleBar.GetTitleLabel()){ADD_LOGD("CDlgComBase::IsCaption() return true");return true;}ADD_LOGD("CDlgComBase::IsCaption() return false");return false;
}void CDlgComBase::SetTitleBarObjectName(QString strObjectName)
{m_frameComTitleBar.setObjectName(strObjectName);
}void CDlgComBase::OnTimerCenter()
{CenterInParent((QWidget*)parent());
}void CDlgComBase::SetHeadBarHeight(int nHeight)
{m_frameComTitleBar.setFixedHeight(nHeight);CDlgShadow::SetHeadBarHeight(nHeight);
}void CDlgComBase::ShowMaximized()
{m_frameComTitleBar.ShowMaximized();CDlgShadow::ShowMaximized();
}void CDlgComBase::OnNcLBtnDbClick(int nXPos, int nYPos)
{if (m_bHasMaxFun)m_frameComTitleBar.ShowMaxRestoreBtn(m_bMaximized);CDlgShadow::OnNcLBtnDbClick(nXPos, nYPos);
}

DlgShadow.h

#ifndef SHADOWDLG_H
#define SHADOWDLG_H
#include <QDialog>
#include <QMouseEvent>class CDlgShadow : public QDialog
{Q_OBJECTpublic:CDlgShadow(QWidget *parent = 0);~CDlgShadow();void HideDlg();void ShowDlg();void SetDlgBkColor(QColor& clrDlgBk);void CenterInParent(QWidget* pWidget);void SetResizeable(bool bOn) { m_bResizeable = bOn; }virtual void OnBtnSettingClicked(QPoint& ptBtnBottom);virtual void OnBtnMinClicked();virtual void OnBtnMaxClicked();virtual void OnBtnRestoreClicked();virtual void OnBtnCloseClicked();virtual bool OnProHotKey(int nFsModifiers, int nVk);virtual void OnMsgEndSession();void ShowMaximized();protected:void paintEvent(QPaintEvent* event);void keyPressEvent(QKeyEvent* event);int GetShadowLen() { return m_nShadowLen; }int GetHeadBarHeight() { return m_nHeadBarHeight; }void SetHeadBarHeight(int nHeight);void SetHasMaxFun(bool bHasMaxFun) { m_bHasMaxFun = bHasMaxFun; }bool nativeEvent(const QByteArray& eventType, void* pMessage, long* pResult);virtual bool IsCaption(int nXPos, int nYPos);virtual void OnNcLBtnDbClick(int nXPos, int nYPos);virtual void OnKeyReturnPress();virtual void OnKeyEscapePress();virtual void OnNcLBtnClick();void closeEvent(QCloseEvent *event);protected:int					m_nFrameLen;		// 边框宽度，单位：像素int					m_nShadowLen;		// 阴影宽度，单位：像素int					m_nHeadBarHeight;	// 标题栏高度bool				m_bHasMaxFun;bool				m_bMaximized;bool				m_bNcLBtnClk;bool				m_bHideDlg;QString				m_strTitle;			// 调试时使用bool				m_bHotKey;			// 处理快捷键功能private:QRect				m_rectDlg;QColor				m_clrDlgBk;bool				m_bResizeable;
};#endif // SHADOWDLG_H

DlgShadow.cpp

#include "DlgShadow.h"
#include <QPainter>
#include <qmath.h>
#include <QApplication>
#include <QDesktopWidget>
#include <Windows.h>CDlgShadow::CDlgShadow(QWidget *parent): QDialog(parent)
{setWindowFlags(Qt::FramelessWindowHint | Qt::Dialog | Qt::WindowMinimizeButtonHint);setAttribute(Qt::WA_TranslucentBackground);m_nFrameLen = 10;m_nShadowLen = 6;m_nHeadBarHeight = 36;m_bMaximized = false;m_bHasMaxFun = true;m_clrDlgBk = QColor(255, 255, 255);m_bResizeable = true;m_bNcLBtnClk = false;m_bHideDlg = false;m_bHotKey = false;
}CDlgShadow::~CDlgShadow()
{}void CDlgShadow::paintEvent(QPaintEvent* event)
{QPainterPath path;path.setFillRule(Qt::WindingFill);path.addRoundedRect(m_nShadowLen, m_nShadowLen, width() - 2 * m_nShadowLen, height() - 2 * m_nShadowLen, 2, 2);QPainter painter(this);painter.setRenderHint(QPainter::Antialiasing, true);painter.fillPath(path, QBrush(m_clrDlgBk));QColor color(0, 0, 0, 50);for (int i = 0; i < m_nShadowLen; i++){QPainterPath pathShadow;pathShadow.setFillRule(Qt::WindingFill);pathShadow.addRoundedRect(m_nShadowLen - i, m_nShadowLen - i, width() - (m_nShadowLen - i) * 2, height() - (m_nShadowLen - i) * 2, 2 + i, 2 + i);int nAlpha = 50 - qSqrt(i) * 25;if (nAlpha < 0)nAlpha = 0;color.setAlpha(nAlpha);painter.setPen(color);painter.drawPath(pathShadow);}painter.setRenderHint(QPainter::Antialiasing, false);painter.fillPath(path, QBrush(m_clrDlgBk));QDialog::paintEvent(event);
}void CDlgShadow::OnBtnMinClicked()
{showMinimized();
}void CDlgShadow::OnBtnMaxClicked()
{m_bMaximized = true;m_rectDlg = geometry();setGeometry(-m_nShadowLen, -m_nShadowLen, QApplication::desktop()->availableGeometry().width() + m_nShadowLen * 2,QApplication::desktop()->availableGeometry().height() + m_nShadowLen * 2);
}void CDlgShadow::OnBtnRestoreClicked()
{m_bMaximized = false;setFixedHeight(QWIDGETSIZE_MAX);setGeometry(m_rectDlg);
}void CDlgShadow::SetDlgBkColor(QColor& clrDlgBk)
{m_clrDlgBk = clrDlgBk;
}void CDlgShadow::SetHeadBarHeight(int nHeight)
{m_nHeadBarHeight = nHeight; 
}bool CDlgShadow::IsCaption(int nXPos, int nYPos)
{if (childAt(nXPos, nYPos) == 0){ADD_LOGD("CDlgShadow::IsCaption() return true");return true;}else{ADD_LOGD("CDlgShadow::IsCaption() return false");return false;}
}bool CDlgShadow::nativeEvent(const QByteArray& eventType, void* pMessage, long* pResult)
{ADD_LOGD(QString("CDlgShadow::nativeEvent in"));if (m_bHideDlg){ADD_LOGD(QString("CDlgShadow::nativeEvent out"));return QDialog::nativeEvent(eventType, pMessage, pResult);}const MSG* pMsg = static_cast<MSG*>(pMessage);if (pMsg->message == WM_NCHITTEST){RECT rect;SystemParametersInfo(SPI_GETWORKAREA, 0, &rect, 0);int nWin32Width = rect.right - rect.left;int nWin32Height = rect.bottom - rect.top;int nQtWidth = QApplication::desktop()->availableGeometry().width();int nQtHeight = QApplication::desktop()->availableGeometry().height();int nMsgX = ((int)(short)LOWORD(pMsg->lParam)) * nQtWidth / nWin32Width;int nMsgY = ((int)(short)HIWORD(pMsg->lParam)) * nQtHeight / nWin32Height;int xPos = nMsgX - frameGeometry().x();int yPos = nMsgY - frameGeometry().y();if (IsCaption(xPos, yPos)){*pResult = HTCAPTION;}else{ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_NCHITTEST pResult:%1").arg(*pResult));return false;}if (!m_bResizeable){if (*pResult == HTCAPTION){ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_NCHITTEST pResult:%1").arg(*pResult));return true;}ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_NCHITTEST pResult:%1").arg(*pResult));return QDialog::nativeEvent(eventType, pMessage, pResult);}if (xPos > 0 && xPos < m_nFrameLen)*pResult = HTLEFT;if (xPos >(width() - m_nFrameLen) && xPos < (width() - 0))*pResult = HTRIGHT;if (yPos > 0 && yPos < m_nFrameLen)*pResult = HTTOP;if (yPos >(height() - m_nFrameLen) && yPos < (height() - 0))*pResult = HTBOTTOM;if (xPos > 0 && xPos < m_nFrameLen && yPos > 0 && yPos < m_nFrameLen)*pResult = HTTOPLEFT;if (xPos >(width() - m_nFrameLen) && xPos < (width() - 0) && yPos > 0 && yPos < m_nFrameLen)*pResult = HTTOPRIGHT;if (xPos > 0 && xPos < m_nFrameLen && yPos >(height() - m_nFrameLen) && yPos < (height() - 0))*pResult = HTBOTTOMLEFT;if (xPos >(width() - m_nFrameLen) && xPos < (width() - 0) && yPos >(height() - m_nFrameLen) && yPos < (height() - 0))*pResult = HTBOTTOMRIGHT;ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_NCHITTEST pResult:%1").arg(*pResult));return true;}else if (pMsg->message == WM_NCLBUTTONDBLCLK){int xPos = ((int)(short)LOWORD(pMsg->lParam)) - frameGeometry().x();int yPos = ((int)(short)HIWORD(pMsg->lParam)) - frameGeometry().y();OnNcLBtnDbClick(xPos, yPos);ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_NCLBUTTONDBLCLK"));return true;}else if (pMsg->message == WM_NCLBUTTONDOWN){if (m_bNcLBtnClk){OnNcLBtnClick();}}else if (pMsg->message == WM_HOTKEY){if (m_bHotKey){UINT nFuModifiers = (UINT)LOWORD(pMsg->lParam);  // 模式UINT nVirtKey = (UINT)HIWORD(pMsg->lParam);     // 键值if (OnProHotKey(nFuModifiers, nVirtKey)){ADD_LOGD(QString("CDlgShadow::nativeEvent out, WM_HOTKEY"));return true;}}}else if (pMsg->message == WM_ENDSESSION){ADD_LOGD(QStringLiteral("截获关机指令1"));OnMsgEndSession();}ADD_LOGD(QString("CDlgShadow::nativeEvent out"));return QDialog::nativeEvent(eventType, pMessage, pResult);
}void CDlgShadow::OnNcLBtnDbClick(int nXPos, int nYPos)
{if (!m_bHasMaxFun)return;if (nYPos > m_nFrameLen + m_nHeadBarHeight)return;if (m_bMaximized){OnBtnRestoreClicked();}else{OnBtnMaxClicked();}
}void CDlgShadow::CenterInParent(QWidget* pWidget)
{int nXPos = 0;int nYPos = 0;if (pWidget == NULL){nXPos = (QApplication::desktop()->width() - width()) / 2;nYPos = (QApplication::desktop()->height() - height()) / 2;}else{QWidget* pParent = (QWidget*)pWidget->parent();
// 		if (pParent != NULL)
// 		{
// 			//QPoint ptGloba = pWidget->mapToGlobal(QPoint(0, 0));
// 			nXPos = /*ptGloba.x() + */(pWidget->width() - width()) / 2;
// 			nYPos = /*ptGloba.y() + */(pWidget->height() - height()) / 2;
// 		}
// 		else{QPoint ptGloba = pWidget->mapToGlobal(QPoint(0, 0));nXPos = ptGloba.x() + (pWidget->width() - width()) / 2;nYPos = ptGloba.y() + (pWidget->height() - height()) / 2;}}move(nXPos, nYPos);
}void CDlgShadow::keyPressEvent(QKeyEvent* event)
{if (event->key() == Qt::Key_Enter || event->key() == Qt::Key_Return/* || event->key() == Qt::Key_Space*/){OnKeyReturnPress();event->accept();}else if (event->key() == Qt::Key_Escape){OnKeyEscapePress();event->ignore();}
}void CDlgShadow::OnKeyReturnPress()
{//accept();
}void CDlgShadow::OnKeyEscapePress()
{//reject();
}void CDlgShadow::OnBtnCloseClicked()
{reject();
}void CDlgShadow::OnBtnSettingClicked(QPoint& ptBtnBottom)
{}void CDlgShadow::OnNcLBtnClick()
{}void CDlgShadow::HideDlg()
{m_bHideDlg = true;setWindowOpacity(0);
}void CDlgShadow::ShowDlg()
{setWindowOpacity(1);m_bHideDlg = false;
}void CDlgShadow::closeEvent(QCloseEvent *event)
{event->ignore();OnBtnCloseClicked();
}bool CDlgShadow::OnProHotKey(int nFsModifiers, int nVk)
{return false;
}void CDlgShadow::OnMsgEndSession()
{}void CDlgShadow::ShowMaximized()
{m_bMaximized = true;int nXPos = (QApplication::desktop()->availableGeometry().width() - (1273 + 11)) / 2;int nYPos = (QApplication::desktop()->availableGeometry().height() - (878 + 11)) / 2;int nMaxHeight = QApplication::desktop()->availableGeometry().height() + m_nShadowLen * 2;//setFixedHeight(nMaxHeight);setFixedHeight(QWIDGETSIZE_MAX);m_rectDlg = QRect(nXPos, nYPos, (1273 + 11), (878 + 11));setGeometry(-m_nShadowLen, -m_nShadowLen, QApplication::desktop()->availableGeometry().width() + m_nShadowLen * 2,QApplication::desktop()->availableGeometry().height() + m_nShadowLen * 2);
}