Qt去除图像的背景色? [复制链接]

       现在有几个png的图案,不过他的背景色是红色,我想利用QPixmap里面的遮罩去除掉背景色,
       不过试了一下完全没作用,请问有人熟Qt图型处理的类吗?
      原码:

         QLabel label;
         QPixmap.pixmap(xxx.png);
          pixmap.createMaskFromColor(QColor(255,0,0),Qt::MaskOutColor);
          label->setPixmap(pixmap);

         是我的用法错误吗?拜托了举个例子让我学习

QPixmap pixmap("c:/6.JPG");
    QBitmap bmp=pixmap.createMaskFromColor(QColor(0,0,0));
    pixmap.setMask(bmp);
    QLabel *label=new QLabel(this);
    label->setGeometry(100,100,100,100);
    label->setScaledContents(true);
    label->setPixmap(pixmap);

所以可能你少了setMask这一步吧！

QWidget::setAttribute(Qt::WA_TranslucentBackground);

Indicates that the widget should have a translucent background, i.e., any non-opaque regions of the widgets will be translucent because the widget will have an alpha channel. Setting this flag causes WA_NoSystemBackground to be set. On Windows the widget also needs the Qt::FramelessWindowHint window flag to be set. This flag is set or cleared by the widget's author.