Question

I have strange problem I have item delegate inherit from QStyledItemDelegate the background color is gradient color that looks like this:

void ItemDelegate::paintActiveOverlay( QPainter* painter,
                                       qreal x,
                                       qreal y,
                                       qreal w,
                                       qreal h ) const 
{
    QPalette palette;
    QColor highlightColor = palette.color(QPalette::Highlight);
    QColor backgroundColor = palette.color(QPalette::Base);
    const float animation = 0.25;
    const int gradientRange = 16;

    QColor color2 = QColor::fromHsv(
        highlightColor.hue(),
        (int) (backgroundColor.saturation() * (1.0f - animation) + 
        highlightColor.saturation() * animation),
        (int) (backgroundColor.value() * (1.0f - animation) + 
        highlightColor.value() * animation) );

    QColor color1 = QColor::fromHsv(
        color2.hue(),
        qMax(color2.saturation() - gradientRange, 0),
        qMin(color2.value() + gradientRange, 255) );

    QRect rect( (int)x, (int)y, (int)w, (int)h);

    painter->save();
    painter->setPen(Qt::NoPen);

    QLinearGradient linearGradient(0, 0, 0, rect.height());
    linearGradient.setColorAt(0.0, color1);
    linearGradient.setColorAt(1.0, color2);

    painter->setBrush(linearGradient);
    painter->drawRect(rect);
    painter->restore();
}

It s called from the paint method also in the ItemDelegate constructor I have set QLabel like this:

 QRect rect(40, 30, 401, 31);
 Qt::TextInteractionFlags flags =     
      Qt::LinksAccessibleByKeyboard | 
      Qt::LinksAccessibleByMouse    |
      Qt::TextBrowserInteraction    |
      Qt::TextSelectableByKeyboard  |
      Qt::TextSelectableByMouse;
 Qt::TextFormat txtFormat = Qt::PlainText;

 pTextEdit_title = new QLabel();
 pTextEdit_title->setTextFormat(txtFormat);
 pTextEdit_title->setTextInteractionFlags(flags);
 pTextEdit_title->setGeometry(rect);

以及<代码>的油漆方法项目Delegate i set the QLabel to make such as:

  pTextEdit_title->setText(Title);
  QRect TextEditRect(option.rect.x()+THUMB_WIDTH+THUMB_WIDTH+PADDING, option.rect.y() ,
  pTextEdit_title->width(), pTextEdit_title->height());
  QPixmap pixmap(pTextEdit_title->size());
  pTextEdit_title->render(&pixmap);
  painter->drawPixmap(TextEditRect,pixmap);

it render the QLabel file , but the problem is that it has gray background and doesnt act as transparent background , my question is how to set the QLabel background to be transparent?
also why the TextInteractionFlags i set bean ignored i can t do any thing to the text.

Answer 1

有色透明度取决于alpha 输送:

The alpha channel of a color specifies the transparency effect, 0 represents a fully transparent color, while 255 represents a fully opaque color.

By default it is 255 so you should specify the desired value as a fourth argument at the fromHsv functions you are using.

也可使用setAlpha。

Answer 2

在提供植被时,总是会发现植被背景。有一种特别的旗帜,可以消除植被背景。

qwidget api的手册对此作了解释。

Answer 3

我也遇到了同样的问题。

最终通过确定属性<代码>开展工作。 Qt:WA_TranslucentBackground on http://www.wdget->render()

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