def _on_point_list_contents_changed(self):
if not self._points:
return
if len(self._points) == 1:
# Delete only point's line segment
try:
edge_item = self.point_items[self._points[0]].edge_item
except AttributeError:
return
if edge_item.scene():
edge_item.scene().removeItem(edge_item)
del self.point_items[self._points[0]].edge_item
return
# Make and update edges (line segments) as needed
pis = [(point, self.point_items[point]) for point in self._points]
for (point1, point_item1), (point2, point_item2) in zip(pis, pis[1:]):
line = Qt.QLineF(point1.x, point1.y, point2.x, point2.y)
if not hasattr(point_item1, 'edge_item'):
point_item1.edge_item = Qt.QGraphicsLineItem(
line, self.parentItem())
point_item1.edge_item.setPen(self.line_pen)
point_item1.edge_item.installSceneEventFilter(self)
point_item1.edge_item.setZValue(-1)
elif point_item1.edge_item.line() != line:
point_item1.edge_item.setLine(line)
# Delete last point's line segment
try:
edge_item = self.point_items[self._points[-1]].edge_item
except AttributeError:
return
if edge_item.scene():
edge_item.scene().removeItem(edge_item)
del self.point_items[self._points[-1]].edge_item
def _on_point_item_list_content_reset(self):
for line_item in self.line_items:
self.view.scene().removeItem(line_item)
self.line_items = []
if len(self.point_items) > 1:
for point_item1, point_item2 in zip(self.point_items,
self.point_items[1:]):
line_item = Qt.QGraphicsLineItem(
Qt.QLineF(point_item1.pos(), point_item2.pos()),
self.parentItem())
line_item.setPen(self.line_pen)
line_item.installSceneEventFilter(self)
line_item.setZValue(-1)
self.line_items.append(line_item)
def make_and_store_point_item(self, pos):
self._ignore_point_item_position_changed = True
try:
super().make_and_store_point_item(pos)
finally:
self._ignore_point_item_position_changed = False
if len(self.point_items) > 1:
p1 = self.point_items[-2].pos()
line_item = Qt.QGraphicsLineItem(Qt.QLineF(p1, pos),
self.parentItem())
line_item.setPen(self.line_pen)
line_item.installSceneEventFilter(self)
line_item.setZValue(-1)
self.line_items.append(line_item)
