def bg_item(self):
"""return a canvas item for the shape in the background"""
bg = QtWidgets.QGraphicsPolygonItem()
poly = QtGui.QPolygonF()
poly.append(QtCore.QPointF(-5, 5))
poly.append(QtCore.QPointF(15, -5))
poly.append(QtCore.QPointF(35, 5))
poly.append(QtCore.QPointF(15, 15))
bg.setPolygon(poly)
return bg
def setLine(self, x0, y0, x1, y1, hierarchyLink=False):
self.line.setLine(x0, y0, x1, y1)
x, y = x1 - (x1 - x0) / 3., y1 - (y1 - y0) / 3.
if not hierarchyLink:
r = 12.
else:
r = 6.
a = atan2(y1 - y0, x1 - x0)
w = 2.79252680
pts = [
QtCore.QPointF(x, y),
QtCore.QPointF(x + r * cos(a + w), y + r * sin(a + w)),
QtCore.QPointF(x + r * cos(a - w), y + r * sin(a - w)),
# QtCore.QPointF(x, y),
]
self.head.setPolygon(QtGui.QPolygonF(pts))
