QT implements a shadow form similar to QQ

#ifndef bfwidget_h#define bfwidget_h#include <QWidget> #include <QMouseEvent> #include <qresizeevent >/** * Window can drag * window to add shadow effect * @brief the Bfwidget class */class bfwidget:public qwidget{    q_objectpublic:    explici T Bfwidget (Qwidget *parent = 0);    /**     * Rewrite spatial typesetting settings     * Place the space on the central_widget     * @brief setlayout     * @param layout     *    /void setlayout ( Qlayout * layout); Signals:public slots:protected:    void Mousepressevent (Qmouseevent *event);    void Mousereleaseevent (Qmouseevent *event);    void Mousemoveevent (Qmouseevent *event);    void Resizeevent (qresizeevent *event);p rivate:    //area to display content    qwidget     *central_widget;    Qpoint Move_point; Move the distance    bool mouse_press;//Press left mouse button}; #endif//Bfwidget_h

<pre name= "code" class= "CPP" > #include <QBoxLayout> #include <QPalette> #include < qgraphicsdropshadoweffect> #include <QDebug> #include <QSizePolicy> #include "bfwidget.h" Bfwidget::    Bfwidget (Qwidget *parent): Qwidget (parent) {setwindowflags (qt::framelesswindowhint);    SetAttribute (Qt::wa_translucentbackground);    Central_widget = new Qwidget (); Central_widget->setsizepolicy (qsizepolicy::expanding,qsizepolicy::expanding);    Horizontal and vertical directions arbitrarily stretched qpalette palette;    Palette.setbrush (Qpalette::background,qbrush (Qcolor (255,255,255)));    Central_widget->setpalette (palette);    Central_widget->setautofillbackground (TRUE);    Qgraphicsdropshadoweffect *shadow_effect = new Qgraphicsdropshadoweffect ();    Shadow_effect->setblurradius (10.0);    Shadow_effect->setcolor (qcolor (0, 0, 0, 100));    Shadow_effect->setoffset (1.0);    Central_widget->setgraphicseffect (Shadow_effect);    Qvboxlayout * main_layout = new qvboxlayout (); Main_laYout->addwidget (Central_widget, Qt::aligncenter);    Main_layout->addspacing (0);    Main_layout->setcontentsmargins (5,5,5,5); Qwidget::setlayout (main_layout);} void Bfwidget::setlayout (Qlayout *layout) {central_widget->setlayout (layout);}    void Bfwidget::mousepressevent (Qmouseevent * Event) {//can only be left mouse button move and change size if (event->button () = = Qt::leftbutton)    {mouse_press = true; }//window move Distance move_point = Event->globalpos ()-POS ();} void Bfwidget::mousereleaseevent (Qmouseevent *) {mouse_press = false;} void Bfwidget::mousemoveevent (Qmouseevent *event) {//Move window if (mouse_press) {Qpoint Move_pos = Event->gl        Obalpos ();    Move (Move_pos-move_point); }}//void bfwidget::resizeevent (qresizeevent *event)//{//qsize size = Event->size ();//Central_widget->setgeom Etry (5, 5, Size.width ()-Ten, Size.Height ()-ten);//Qdebug () << central_widget->rect ();/}

QT implements a shadow form similar to QQ