Am 26.04.2024 um 22:48 schrieb Henry Skoglund:
On 2024-04-26 21:52, Christian Ehrlicher via Development wrote:
Hello,
I'm currently trying to investigate a painting problem within the
windowsvista / common style:
QImage img(7, 7, QImage::Format_ARGB32_Premultiplied);
QPolygon poly{ QPoint(1, 1), {5, 1}, {3, 5} };
QPainter p(&img);
p.setPen(Qt::NoPen);
p.setBrush(QColor(Qt::black));
p.drawPolygon(poly);
p.setPen(QColor(0, 255, 0, 128));
p.drawPoints(poly.data(), poly.size());
p.end();
img.save("output.png");
...
Hi, I think the QPainter draws very poorly using direct polygon paths.
You could try going via a QPainterPath, say:
QImage img(7, 7, QImage::Format_ARGB32_Premultiplied);
img.fill(QColor(0, 255, 0, 128)); // to be sure the img
contains no junk values
QPolygon poly{ QPoint(1, 1), {5, 1}, {3, 5} };
QPainter p(&img);
p.setPen(Qt::NoPen);
p.setBrush(QColor(Qt::black));
p.setPen(QColor(0, 255, 0, 128));
QPainterPath path;
path.addPolygon(poly);
p.drawPath(path);
p.end();
img.save("output.png");
Rgrds Henry
This helped a little bit but it then fails again for other sizes. It's a
mess :(
I'm shortly before drawing the triangles pixel by pixel by myself...
Christian
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