QImage weird artifacts when drawing with QPainter

[Infestor]

Hi,

Im new to Qt and am currently experimenting with QPainter/Image. Consider the following code:

 QImage blankmap; //white image of size 1470*850
    blankmap.load("images/maps/blankmap.png");


    QImage gray; // gray 10*10 image
    gray.load("gray.png");

    QPainter painter;

    painter.begin(&blankmap);
    QRect r(0, 0, 10, 10);
    for (int i = 0; i < 1470; i += 10) {
        for (int j = 0; j < 850; j += 10) {
            r.setX(i);
            r.setY(j);
            painter.drawImage(r, gray);
        }
    }
    painter.end();
    blankmap.save("map1.png");

My expectation now would be that the resulting image is just gray. However as you can see it has two white stripes. Can someone explain this to me?

[Christian Ehrlicher]

Your rectangle is wrong. See QRect::setX() and QRect::setY().

[Infestor]

Is there a functoin that does what i want it to do? At first glance it seems like there is not. Translate() looks like it would work though.

[Christian Ehrlicher]

@Infestor said in QImage weird artifacts when drawing with QPainter:

Is there a functoin that does what i want it to do? At first glance it seems like there is not.

Then you should take a second look. You want to move your rectangle.