[Qt]FrameLessWindow实现调整大小、移动弹窗并具有Aero效果_qmainwindow framelesss

说明

我们知道QWidget等设置了this->setWindowFlags(Qt::FramelessWindowHint);后无法移动和调整大小，但实际项目中是需要窗口能够调整大小的。所以以实现FrameLess弹窗调整大小及移动弹窗需求，并且在Windows 10上有Aero效果。
先看一下效果：

代码

大部分参考这个github。然后自己修改了一下，因为github上面的，在设置了qss后怎么也实现不了窗口圆角以阴影。下面修改版的代码可以实现圆角，但也没有阴影，只能在Widget中自己实现阴影了。
如果不需要圆角，github上面的也是会自带阴影的。不用下面的调整版实现方案。

#ifndef AEROMAINWINDOW_H
#define AEROMAINWINDOW_H

#include <QMainWindow>

class AeroMainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit AeroMainWindow(QWidget *parent = nullptr);
    ~AeroMainWindow();

    //设置是否可以通过鼠标调整窗口大小
    //if resizeable is set to false, then the window can not be resized by mouse
    //but still can be resized programtically
    void setResizeable(bool resizeable=true);
    bool isResizeable(){return m_bResizeable;}

    //设置可调整大小区域的宽度，在此区域内，可以使用鼠标调整窗口大小
    //set border width, inside this aera, window can be resized by mouse
    void setResizeableAreaWidth(int width = 5);

protected:
    //设置一个标题栏widget，此widget会被当做标题栏对待
    //set a widget which will be treat as SYSTEM titlebar
    void setTitleBar(QWidget* titlebar);

    //在标题栏控件内，也可以有子控件如标签控件“label1”，此label1遮盖了标题栏，导致不能通过label1拖动窗口
    //要解决此问题，使用addIgnoreWidget(label1)
    //generally, we can add widget say "label1" on titlebar, and it will cover the titlebar under it
    //as a result, we can not drag and move the MainWindow with this "label1" again
    //we can fix this by add "label1" to a ignorelist, just call addIgnoreWidget(label1)
    void addIgnoreWidget(QWidget* widget);

    bool nativeEvent(const QByteArray &eventType, void *message, long *result);
    void resizeEvent(QResizeEvent *event);

public slots:

private slots:
    void onTitleBarDestroyed();

private:
    QWidget *m_titleBar;
    QList<QWidget*> m_whiteList;
    int m_borderWidth;
    bool m_bResizeable;
};

#endif // AEROMAINWINDOW_H
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#include "aeromainwindow.h"

#include <QGraphicsDropShadowEffect>
#include <QDesktopServices>
#include <QUrl>
#include <QGridLayout>
#include <QStyle>
#include <QDebug>
#include <QPushButton>

#ifdef Q_OS_WIN
#include <windows.h>
#include <WinUser.h>
#include <windowsx.h>
#include <dwmapi.h>
#include <objidl.h> // Fixes error C2504: 'IUnknown' : base class undefined
#include <gdiplus.h>
#include <GdiPlusColor.h>
#pragma comment (lib,"Dwmapi.lib") // Adds missing library, fixes error LNK2019: unresolved external symbol __imp__DwmExtendFrameIntoClientArea
#pragma comment (lib,"user32.lib")
#endif

AeroMainWindow::AeroMainWindow(QWidget *parent) :
    QMainWindow(parent),
    m_titleBar(Q_NULLPTR),
    m_borderWidth(5),
    m_bResizeable(true)
{
    this->setAttribute(Qt::WA_TranslucentBackground);//设置窗口背景透明
    this->setWindowFlags(Qt::FramelessWindowHint); //设置无边框窗口

    this->setResizeable(true);
}

AeroMainWindow::~AeroMainWindow()
{
}

void AeroMainWindow::setResizeable(bool resizeable)
{
    bool visible = isVisible();
    m_bResizeable = resizeable;

    if (m_bResizeable)
    {
        setWindowFlags(windowFlags() | Qt::WindowMaximizeButtonHint);
        //此行代码可以带回Aero效果，同时也带回了标题栏和边框,在nativeEvent()会再次去掉标题栏
        //
        //this line will get titlebar/thick frame/Aero back, which is exactly what we want
        //we will get rid of titlebar and thick frame again in nativeEvent() later
        HWND hwnd = (HWND)this->winId();
        DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);
        ::SetWindowLong(hwnd, GWL_STYLE, style | WS_MAXIMIZEBOX | WS_THICKFRAME | WS_CAPTION);
    }
    else
    {
        setWindowFlags(windowFlags() & ~Qt::WindowMaximizeButtonHint);

        HWND hwnd = (HWND)this->winId();
        DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);
        ::SetWindowLong(hwnd, GWL_STYLE, style & ~WS_MAXIMIZEBOX & ~WS_CAPTION);
    }

    //保留一个像素的边框宽度，否则系统不会绘制边框阴影
    const MARGINS shadow = { 1, 1, 1, 1 };
    DwmExtendFrameIntoClientArea(HWND(winId()), &shadow);

    setVisible(visible);
}

void AeroMainWindow::setResizeableAreaWidth(int width)
{
    if (1 > width) width = 1;
    m_borderWidth = width;
}

void AeroMainWindow::setTitleBar(QWidget* titlebar)
{
    m_titleBar = titlebar;
    if (!titlebar) return;
    connect(titlebar, SIGNAL(destroyed(QObject*)), this, SLOT(onTitleBarDestroyed()));
}

void AeroMainWindow::onTitleBarDestroyed()
{
    if (m_titleBar == QObject::sender())
    {
        m_titleBar = Q_NULLPTR;
    }
}

void AeroMainWindow::addIgnoreWidget(QWidget* widget)
{
    if (!widget) return;
    if (m_whiteList.contains(widget)) return;
    m_whiteList.append(widget);
}

bool AeroMainWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)
{
    MSG* msg = (MSG *)message;
    switch (msg->message)
    {
    case WM_NCCALCSIZE:
    {
        //this kills the window frame and title bar we added with
        //WS_THICKFRAME and WS_CAPTION
        *result = 0;
        return true;
    } // WM_NCCALCSIZE
    case WM_NCHITTEST:
    {
        *result = 0;
        const LONG border_width = m_borderWidth; //in pixels
        RECT winrect;
        GetWindowRect(HWND(winId()), &winrect);

        long x = GET_X_LPARAM(msg->lParam);
        long y = GET_Y_LPARAM(msg->lParam);

        if(m_bResizeable)
        {
            bool resizeWidth = minimumWidth() != maximumWidth();
            bool resizeHeight = minimumHeight() != maximumHeight();

            if(resizeWidth)
            {
                //left border
                if (x >= winrect.left && x < winrect.left + border_width)
                {
                    *result = HTLEFT;
                }
                //right border
                if (x < winrect.right && x >= winrect.right - border_width)
                {
                    *result = HTRIGHT;
                }
            }
            if(resizeHeight)
            {
                //bottom border
                if (y < winrect.bottom && y >= winrect.bottom - border_width)
                {
                    *result = HTBOTTOM;
                }
                //top border
                if (y >= winrect.top && y < winrect.top + border_width)
                {
                    *result = HTTOP;
                }
            }
            if(resizeWidth && resizeHeight)
            {
                //bottom left corner
                if (x >= winrect.left && x < winrect.left + border_width &&
                        y < winrect.bottom && y >= winrect.bottom - border_width)
                {
                    *result = HTBOTTOMLEFT;
                }
                //bottom right corner
                if (x < winrect.right && x >= winrect.right - border_width &&
                        y < winrect.bottom && y >= winrect.bottom - border_width)
                {
                    *result = HTBOTTOMRIGHT;
                }
                //top left corner
                if (x >= winrect.left && x < winrect.left + border_width &&
                        y >= winrect.top && y < winrect.top + border_width)
                {
                    *result = HTTOPLEFT;
                }
                //top right corner
                if (x < winrect.right && x >= winrect.right - border_width &&
                        y >= winrect.top && y < winrect.top + border_width)
                {
                    *result = HTTOPRIGHT;
                }
            }
        }
        if (0 != *result) return true;

        //*result still equals 0, that means the cursor locate OUTSIDE the frame area
        //but it may locate in titlebar area
        if (!m_titleBar) return false;

        //support highdpi
        double dpr = this->devicePixelRatioF();
        QPoint pos = m_titleBar->mapFromGlobal(QPoint(x/dpr,y/dpr));

        if (!m_titleBar->rect().contains(pos)) return false;
        QWidget* child = m_titleBar->childAt(pos);
        if (!child)
        {
            *result = HTCAPTION;
            return true;
        }
        else
        {
            if (m_whiteList.contains(child))
            {
                *result = HTCAPTION;
                return true;
            }
        }
        return false;
    } // WM_NCHITTEST
    default:
        return QMainWindow::nativeEvent(eventType, msg, result);
    }
}

void AeroMainWindow::resizeEvent(QResizeEvent *event)
{
    if (m_titleBar)
        m_titleBar->setGeometry(QRect(0, 0, this->rect().width(), m_titleBar->rect().height()));

    QMainWindow::resizeEvent(event);
}
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测试代码

生成一个类，继承上面的类。然后实现下面的内容。很简单：

#include "testmainwindow.h"
#include "ui_testmainwindow.h"

TestMainWindow::TestMainWindow(QWidget *parent) :
    AeroMainWindow(parent),
    ui(new Ui::TestMainWindow)
{
    ui->setupUi(this);

    QWidget *titleBar = new QWidget(this);
    titleBar->setGeometry(QRect(0, 0, this->rect().width(), 25));
    this->setTitleBar(titleBar);

    this->setStyleSheet("background-color: red;\
                         border-radius: 8px;");
}

TestMainWindow::~TestMainWindow()
{
    delete ui;
}
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