funcgraph.py 文件源码

def paint(self, painter, option, widget):
        if not self.source or not self.dest:
            return

        # Draw the line itself.
        line = QLineF(self.sourcePoint, self.destPoint)

        if line.length() == 0.0:
            return

        painter.setPen(QPen(Qt.black, 1, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
        painter.drawLine(line)

        # Draw the arrows if there's enough room.
        angle = math.acos(line.dx() / line.length())
        if line.dy() >= 0:
            angle = VGraphEdge.TwoPi - angle

        sourceArrowP1 = self.sourcePoint + QPointF(math.sin(angle + VGraphEdge.Pi / 3) * self.arrowSize,
                                                          math.cos(angle + VGraphEdge.Pi / 3) * self.arrowSize)
        sourceArrowP2 = self.sourcePoint + QPointF(math.sin(angle + VGraphEdge.Pi - VGraphEdge.Pi / 3) * self.arrowSize,
                                                          math.cos(angle + VGraphEdge.Pi - VGraphEdge.Pi / 3) * self.arrowSize);
        destArrowP1 = self.destPoint + QPointF(math.sin(angle - VGraphEdge.Pi / 3) * self.arrowSize,
                                                      math.cos(angle - VGraphEdge.Pi / 3) * self.arrowSize)
        destArrowP2 = self.destPoint + QPointF(math.sin(angle - VGraphEdge.Pi + VGraphEdge.Pi / 3) * self.arrowSize,
                                                      math.cos(angle - VGraphEdge.Pi + VGraphEdge.Pi / 3) * self.arrowSize)

        painter.setBrush(Qt.black)
        painter.drawPolygon(QPolygonF([line.p1(), sourceArrowP1, sourceArrowP2]))
        painter.drawPolygon(QPolygonF([line.p2(), destArrowP1, destArrowP2]))