WinAPIShadowWidget.cpp

/**
 * 去掉标题之后添加边框阴影
 *
 * WinAPIShadowWidget.cpp
 * 调用Windows相关AP来实现边框阴影的cpp文件。
 *
 * FlyWM_
 * GitHub: https://github.com/FlyWM
 * CSDN: https://blog.csdn.net/a844651990
 *
 */

#include "WinAPIShadowWidget.h"
#include "windwmapi.h"
#pragma comment(lib, "user32.lib")
WinAPIShadowWidget::WinAPIShadowWidget(QWidget *parent)
    : QWidget(parent)
{
    resize(400, 300);
    setWindowFlags(windowFlags() | Qt::FramelessWindowHint);
    HWND hwnd = (HWND)this->winId();
    DWORD style = ::GetWindowLong(hwnd, GWL_STYLE);

    // 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
    ::SetWindowLong(hwnd, GWL_STYLE, style | WS_MAXIMIZEBOX | WS_THICKFRAME | WS_CAPTION);
    //we better left 1 piexl width of border untouch, so OS can draw nice shadow around it
    const MARGINS shadow = { 1, 1, 1, 1 };
    WinDwmapi::instance()->DwmExtendFrameIntoClientArea(HWND(winId()), &shadow);
}

bool WinAPIShadowWidget::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;
    }
    default:
        return QWidget::nativeEvent(eventType, message, result);
    }
}