Qt之使用QGraphicsEffect实现阴影、模糊、着色和透明效果

QGraphicsEffect是所有图像特效的子类，其四个子类分别提供了四种标准特效
☆QGraphicsBlurEffect - blurs the item by a given radius
☆QGraphicsDropShadowEffect - renders a dropshadow behind the item
☆QGraphicsColorizeEffect - renders the item in shades of any given color
☆QGraphicsOpacityEffect - renders the item with an opacity

上面是Qt assistant中的介绍，下面以QLabel为例，实现上面四种效果

 源码：

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QGraphicsBlurEffect>
#includ