CODEWITHSUNDEEP
c++qtcolorsqt5qpainter
oobarbazanoo
oobarbazanoo

Reputation: 407

Set the fill color (not the stroke color) for the QPainter in QT

How could I set the fill color (not the stroke color) for the QPainter in QT?

For example, I have a code which is responsible for filling the rectangle. It looks like:

painter.fillRect(fillRect, Qt::SolidPattern);

Where the type of painter is QPainter. Of course, I know that it is possible to specify the color in the case as a second parameter, but I have such a design in my program that it would be a lot better if I could set the painter fill color beforehand (by default the color is black).

I tried to use painter.setBackground(Qt::yellow);, but it did not help.

Hm. According to this we have:

Sets the painter's brush to the given brush.

The painter's brush defines how shapes are filled.

So, I would expect something like

QRect fillRect;
painter.setBrush(QBrush(Qt::yellow));
painter.fillRect(fillRect, Qt::SolidPattern);

to work. But it does not. What am I doing wrong?

After debugging it turns out that the setBrush method does not update the brush color at all: enter image description here

The color rgb stays the same: (0, 0, 0).

Upvotes: 4

Views: 10540

Answers (1)

eyllanesc
eyllanesc

Reputation: 243955

fillRect() accepts a QBrush as a second parameter, so I could use it:

painter.fillRect(r, QBrush(Qt::yellow, Qt::SolidPattern));

Update:

#include <QApplication>
#include <QLabel>
#include <QPainter>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QPixmap pixmap(128, 128);
    pixmap.fill(Qt::transparent);

    QPainter painter(&pixmap);
    QRect r= pixmap.rect();
    painter.setBrush(QBrush(Qt::yellow));
    painter.fillRect(r, painter.brush());
    painter.end();

    QLabel w;
    w.setPixmap(pixmap);
    w.show();

    return a.exec();
}

enter image description here

Upvotes: 5

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