标签：anti corners demo lan set 起点 方法 alt rsize
https://www.cnblogs.com/yuzhould/p/9132493.html
这个函数文档的意思就是画弧，看了文档也不太明白，自己做了demo终于明白了意思
void TestArcTo::paintEvent(QPaintEvent *)
{
QPoint startPt(30, 30);
QRect rect(startPt.x(), startPt.y(), 200, 200);
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing); //抗锯齿
p.fillRect(rect, QColor(255, 255, 255));
int arcR = rect.width()/2;
int rectSize = rect.width();
QPainterPath path;
path.moveTo(startPt.x() + arcR, startPt.y() + arcR); //先移动到圆心
path.arcTo(rect, 00.0f, 180.0f); //以0度起点，逆时针画180度
p.fillPath(path, QBrush(QColor(122, 122, 122)));
}
path.moveTo(startPt.x() + arcR, startPt.y() + arcR); //先移动到圆心 path.arcTo(rect, 90.0f, 180.0f); //以0度起点，逆时针画180度
path.moveTo(startPt.x() + arcR, startPt.y() + arcR); //先移动到圆心 path.arcTo(rect, 90.0f, 180.0f); //以0度起点，逆时针画180度
void TestArcTo::paintEvent(QPaintEvent *)
{
QRect rect(30, 30, 200, 200);
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);
p.fillRect(rect, QColor(255, 255, 0));
int cornerSize = 50; //调节圆角的大小
int arcR = cornerSize/2;
QPainterPath path;
path.moveTo(rect.left() + arcR, rect.top());
path.arcTo(rect.left(), rect.top(), cornerSize, cornerSize, 90.0f, 90.0f);
path.lineTo(rect.left(), rect.bottom() - arcR);
path.arcTo(rect.left(), rect.bottom() - cornerSize, cornerSize, cornerSize, 180.0f, 90.0f);
path.lineTo(rect.right() - arcR, rect.bottom());
path.arcTo(rect.right() - cornerSize, rect.bottom() - cornerSize, cornerSize, cornerSize, 270.0f, 90.0f);
path.lineTo(rect.right(), rect.top() + arcR);
path.arcTo(rect.right() - cornerSize, rect.top(), cornerSize, cornerSize, 0.0f, 90.0f);
p.fillPath(path, QBrush(QColor(122, 122, 122)));
}
底部和右边有黄色边框需要处理，这就需要+1， -1微调了。理解了arcTo函数，都不难处理。
void TestArcTo::paintEvent(QPaintEvent *)
{
QRect rect(30, 30, 200, 200);
QPainter p(this);
p.setRenderHint(QPainter::Antialiasing);
p.fillRect(rect, QColor(255, 255, 0));
p.setPen(Qt::NoPen);
p.setBrush(QColor(122, 122, 122));
p.drawRoundedRect(rect, 20, 20);
}
标签：anti corners demo lan set 起点 方法 alt rsize
原文地址：https://www.cnblogs.com/warmlight/p/11899479.html
