Your issue most likely comes from the fact that you're basing your gradient's "area" on the bounding rect of your item before you set the font size to something much larger than the default.
The bounding rect you're getting is thus much smaller than your actual bounding rect. Since the default spread method is padding, you're seeing most likely just one color (or not enough of the gradient for it to be actually visible).
So move your setFont
call to the top, before you create the gradient. You can drop the setStyle
on your brush, that's determined automatically from the gradient. (In fact, you can drop that brush entirely and use the gradient in setBrush
.)
With the way you set up the gradient, you'll get a "diagonal" gradient. If you want it from top to bottom, use the top left and bottom left points instead.
Demo
#include <QtGui>
class W: public QGraphicsView
{
Q_OBJECT
public:
W(QWidget *parent = 0)
: QGraphicsView(parent)
{
QGraphicsSimpleTextItem *item = new QGraphicsSimpleTextItem;
item->setText("Stack Overflow");
item->setPen(QPen(Qt::red));
item->setFont(QFont("courier", 60, QFont::Bold));
QLinearGradient lgrad(item->boundingRect().topLeft(),
item->boundingRect().bottomLeft());
lgrad.setColorAt(0.0, Qt::red);
lgrad.setColorAt(1.0, Qt::yellow);
item->setBrush(lgrad);
QGraphicsScene *scene = new QGraphicsScene;
scene->setBackgroundBrush(QBrush(Qt::black));
scene->addItem(item);
setScene(scene);
}
};