Qt椭圆边框变薄 [英] Qt Ellipse Border Thins Out

问题描述

我试图在Qt中绘制一个椭圆，并且边缘上的边框在某些地方变细.

I am trying to draw an ellipse in Qt and the border on the edges goes thin in some places.

这是代码:

QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.setPen(QPen(Qt::black, 3));
painter.drawEllipse(event->rect());

有什么想法吗?预先感谢.

Any ideas? Thanks in advance.

推荐答案

在绘制带有轮廓的形状时，必须考虑笔的宽度.因此，根据您的情况，更改为:

When painting a shape with an outline, you have to factor in the width of the pen. So in your case, change to this:

// Adjusted by 2 pixels because half your pen width is 1.5, but QRect is
// for integer types, so rounded up.
painter.drawEllipse(event->rect().adjusted( -2, -2, 2, 2 ) );

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