Qt实现无边框背景加深的对话框

// ui_frameless_dialog.h
#pragma once
#include <QWidget>
#include <QMouseEvent>

class FramelessDialog : public QWidget {
    Q_OBJECT
public:
    FramelessDialog(QWidget* parent = Q_NULLPTR);
    void SetSize(int32_t width, int32_t height, int32_t parent_width, int32_t parent_height);

private:
    void mousePressEvent(QMouseEvent* event) override;

protected:
    QWidget* dialog_;
};

// ui_frameless_dialog.cpp
#include "ui_frameless_dialog.h"

FramelessDialog::FramelessDialog(QWidget* parent) : QWidget(parent), m_pDialog(new QWidget(this)) {
    setAttribute(Qt::WA_StyledBackground, true);
    dialog_->setAttribute(Qt::WA_StyledBackground, true);
}

void FramelessDialog::SetSize(int32_t width, int32_t height, int32_t parent_width, int32_t parent_height) {
    resize(parent_width, parent_height);
    //对话框后面加深
    setStyleSheet("background:rgb(0,0,0,50%);");
    int32_t delta_x = (width() - width) >> 1;
    int32_t delta_y = (height() - height) / 3;
    dialog_->setGeometry(delta_x, delta_y, width, height);
}

void FramelessDialog::mousePressEvent(QMouseEvent* event) {
    //点击对话框外侧关闭
    int32_t pos_x = event->x(), pos_y = event->y();
    if (pos_x < m_pDialog->x() || pos_y < m_pDialog->y() || pos_x > m_pDialog->x() + m_pDialog->width() ||
        pos_y > m_pDialog->y() + m_pDialog->height()) {
        hide();
    }
}