QGraphicsItem画五角星
时间: 2024-01-02 18:14:57 浏览: 28
以下是用QGraphicsItem绘制五角星的示例代码:
```python
from PyQt5.QtGui import QPainter, QPolygonF, QBrush, QColor
from PyQt5.QtCore import Qt, QPointF
from PyQt5.QtWidgets import QGraphicsItem
class StarItem(QGraphicsItem):
def __init__(self, size, color, parent=None):
super().__init__(parent)
self.size = size
self.color = QColor(color)
def boundingRect(self):
return QRectF(-self.size/2, -self.size/2, self.size, self.size)
def paint(self, painter, option, widget=None):
painter.setRenderHint(QPainter.Antialiasing)
painter.setBrush(QBrush(self.color))
points = [QPointF(0, -self.size/2)]
for i in range(4):
angle = (72 + i * 72) * 3.1416 / 180
points.append(QPointF(self.size/2 * sin(angle), -self.size/2 * cos(angle)))
points.append(QPointF(self.size/4 * sin(angle + 36 * 3.1416 / 180), -self.size/4 * cos(angle + 36 * 3.1416 / 180)))
poly = QPolygonF(points)
painter.drawPolygon(poly)
```
其中,size是五角星的大小,color是五角星的颜色。在boundingRect函数中,我们定义了五角星的边界矩形。在paint函数中,我们首先开启了反锯齿渲染,然后设置画刷,接着计算五角星的顶点坐标,并用QPolygonF类构造一个多边形。最后,我们使用drawPolygon方法绘制这个多边形即可。