Qt QPainter 通过鼠标mousePressEvent事件得到起点坐标m_startPoint,通过mouseMoveEvent事件得到终点坐标m_endPoint,通过起点坐标,终点坐标得到一个矩形.qreal x = m_endPoint.rx() - m_startPoint.rx() qreal y = m_endPoint.ry
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/05 05:46:36
![Qt QPainter 通过鼠标mousePressEvent事件得到起点坐标m_startPoint,通过mouseMoveEvent事件得到终点坐标m_endPoint,通过起点坐标,终点坐标得到一个矩形.qreal x = m_endPoint.rx() - m_startPoint.rx() qreal y = m_endPoint.ry](/uploads/image/z/4923823-31-3.jpg?t=Qt+QPainter+%E9%80%9A%E8%BF%87%E9%BC%A0%E6%A0%87mousePressEvent%E4%BA%8B%E4%BB%B6%E5%BE%97%E5%88%B0%E8%B5%B7%E7%82%B9%E5%9D%90%E6%A0%87m_startPoint%2C%E9%80%9A%E8%BF%87mouseMoveEvent%E4%BA%8B%E4%BB%B6%E5%BE%97%E5%88%B0%E7%BB%88%E7%82%B9%E5%9D%90%E6%A0%87m_endPoint%2C%E9%80%9A%E8%BF%87%E8%B5%B7%E7%82%B9%E5%9D%90%E6%A0%87%2C%E7%BB%88%E7%82%B9%E5%9D%90%E6%A0%87%E5%BE%97%E5%88%B0%E4%B8%80%E4%B8%AA%E7%9F%A9%E5%BD%A2.qreal+x+%3D+m_endPoint.rx%28%29+-+m_startPoint.rx%28%29+qreal+y+%3D+m_endPoint.ry)
Qt QPainter 通过鼠标mousePressEvent事件得到起点坐标m_startPoint,通过mouseMoveEvent事件得到终点坐标m_endPoint,通过起点坐标,终点坐标得到一个矩形.qreal x = m_endPoint.rx() - m_startPoint.rx() qreal y = m_endPoint.ry
Qt QPainter
通过鼠标mousePressEvent事件得到起点坐标m_startPoint,通过mouseMoveEvent事件得到终点坐标m_endPoint,通过起点坐标,终点坐标得到一个矩形.
qreal x = m_endPoint.rx() - m_startPoint.rx()
qreal y = m_endPoint.ry() - m_startPoint.ry()
qreal radius = qMin(x ,y );
怎么样以矩形中心(x/2,y/2)为圆点,以radius为半径画圆?
painter->drawEllipse(x/2,y/2 ,radius,radius) 怎么画不出来呢?
结果是什么都画不出!不甚感激!
Qt QPainter 通过鼠标mousePressEvent事件得到起点坐标m_startPoint,通过mouseMoveEvent事件得到终点坐标m_endPoint,通过起点坐标,终点坐标得到一个矩形.qreal x = m_endPoint.rx() - m_startPoint.rx() qreal y = m_endPoint.ry
你不会看帮助手册?
void QPainter::drawEllipse ( int x,int y,int width,int height )
This is an overloaded function.
Draws the ellipse defined by the rectangle beginning at (x,y) with the given width and height.