继承QWidget,自绘制线发现第一条线线宽少了一个像素
void GridCanvas::paintEvent(QPaintEvent *event)
{
QPainter painter(this);
QPen pPenSolid;
pPenSolid.setStyle(Qt::SolidLine); //实线笔
pPenSolid.setWidth(2);
painter.setPen(pPenSolid);
QRect r = this->rect();
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
int x1 = r.left() + (j* r.width() / 3);
int x2 = r.left() + (j + 1)* r.width() / 3;
int y1 = r.top() + i * r.height() / 3;
int y2 = y1;
painter.drawLine(x1,y1,x2,y2);
}
}
}