Qt窗口特殊效果

• 窗口直接透明

setWindowOpacity(0.1);

• 部件不透明，窗体背景完全透明，Windows下需要配合无边框风格

  setWindowFlags(Qt::FramelessWindowHint);
  setAttribute(Qt::WA_TranslucentBackground);

  
• 只设置部件透明

  QGraphicsOpacityEffect * opacityEffect = new QGraphicsOpacityEffect;
  opacityEffect->setOpacity(0.1);
  ui->label->setGraphicsEffect(opacityEffect);

  
• 阴影效果

      
      
  ```cpp
  QGraphicsDropShadowEffect* shadowEffect = new QGraphicsDropShadowEffect;
      //阴影色，透明度
      shadowEffect->setColor(QColor(100,100,100));
      shadowEffect->setBlurRadius(20);//阴影模糊半径
      shadowEffect->setOffset(20);//阴影偏移值
      ui->label->setGraphicsEffect(shadowEffect);

  
• 实现半透明

  //重写paintEvent
  void MainWindow::paintEvent(QPaintEvent* event)
  {   //实现半透明
      QPainter painter(this);
      painter.fillRect(rect(),QColor(255,255,255,256));
  }

• 设置不规则窗体形状

1. 找一个PNG，加到资源文件

2.  pixmap.load(":/flower.png");
    resize(pixmap.size());
    setMask(pixmap.mask());//设置遮罩```
   

3. 重写paintEvent

   void Widget::paintEvent(QPaintEvent *event)
   {
       QPainter painter(this);
       painter.drawPixmap(0,0,QPixmap(":/flower.png"));
   }