# 参考网上的一篇文章, 自已写的例子.
# 解决 QGraphicsItemGroup 不能向他的子 item 传递事件的问题,
# 要改的,并不是 group层的代码,而是他子类的函数:sceneEvent
# setfilterschildevents 并不是这个问题的关键,sethandleschildevents 已经 obsolete , 所以都没用.
# 本例中 有一个 proxy widget的按钮, 在此模式下,可以正常工作.
# 有三种方式可以重载 sceneEvent,
# 1. 派生一个子类, 这里就不做测试了.
# 2. 把原类的函数更改掉. 因为 pyqt 是 qt的python 包装, 并不是 built-in , 所以这种方法,可以实行.
# 3. 更改子类的方法.
# 要注意的是, 方法 2 和方法 3 在实行时, 函数的写法不同. 方法3, 实际上,就是 一个装饰器.
# 方法2 在更改时, 对原代码的影响最小, 但可能是给自己挖坑..
# 方法3 要对每一个实例进行更改, 实际上, 操作可能有些困难, 别的一些写好的函数内部调用时,可能无法实行.
# 具体 选哪种方式, 见仁见智吧.
# python 3.8 , pyqt 5.15
from typing import Callable
from PyQt5 import QtWidgets as qw, QtCore as qc, QtGui as qg
import sys
import numpy as np
# 通过改变类的函数,来重载 event
def change_type_event():
def mouseReleaseEvent(
self: qw.QGraphicsItem, event: "qw.QGraphicsSceneMouseEvent"
) -> None:
print("mouseReleaseEvent", type(self))
if not isinstance(self, qw.QGraphicsProxyWidget):
self.setPen(self._base_pen)
return self._mouseReleaseEvent(self, event)
def mousePressEvent(
self: qw.QGraphicsItem, event: "qw.QGraphicsSceneMouseEvent"
) -> None:
event.accept()
print("mousePressEvent", type(self))
if not isinstance(self, qw.QGraphicsProxyWidget):
self._base_pen = self.pen()
p = qg.QPen()
p.setColor(qg.QColor(255, 0, 0))
p.setWidth(self.pen().width())
self.setPen(p)
return self._mousePressEvent(self, event)
def sceneEvent(self: qw.QGraphicsItem, event: qc.QEvent):
event.accept()
# 有可能会漏了一部分事件的触发
if isinstance(event, qw.QGraphicsSceneMouseEvent):
if event.type() == 155:
self.mouseMoveEvent(event)
elif event.type() == 156:
self.mousePressEvent(event)
elif event.type() == 157:
self.mouseReleaseEvent(event)
elif event.type() == 158:
self.mouseDoubleClickEvent(event)
else:
print("other ", event.type())
elif isinstance(event, qw.QGraphicsSceneContextMenuEvent):
print(type(self), type(event), event.type())
self.contextMenuEvent(event)
else:
self._sceneEvent(self, event)
return True
types = [
qw.QGraphicsLineItem,
qw.QGraphicsPathItem,
qw.QGraphicsPolygonItem,
qw.QGraphicsRectItem,
qw.QGraphicsProxyWidget,
qw.QGraphicsEllipseItem,
]
for tp in types:
assert not hasattr(tp, "_mousePressEvent")
tp._mousePressEvent = tp.mousePressEvent
tp.mousePressEvent = mousePressEvent
assert not hasattr(tp, "_mouseReleaseEvent")
tp._mouseReleaseEvent = tp.mouseReleaseEvent
tp.mouseReleaseEvent = mouseReleaseEvent
assert not hasattr(tp, "_sceneEvent")
tp._sceneEvent = tp.sceneEvent
tp.sceneEvent = sceneEvent
def change_event_item(obj: qw.QGraphicsItem):
def mouseReleaseEvent(event: "qw.QGraphicsSceneMouseEvent") -> None:
print("mouseReleaseEvent", type(obj))
if not isinstance(obj, qw.QGraphicsProxyWidget):
obj.setPen(obj._base_pen)
return obj._mouseReleaseEvent(event)
def mousePressEvent(event: "qw.QGraphicsSceneMouseEvent") -> None:
event.accept()
print("mousePressEvent", type(obj))
if not isinstance(obj, qw.QGraphicsProxyWidget):
obj._base_pen = obj.pen()
p = qg.QPen()
p.setColor(qg.QColor(255, 0, 0))
p.setWidth(obj.pen().width())
obj.setPen(p)
return obj._mousePressEvent(event)
def sceneEvent(event: qc.QEvent):
event.accept()
# 有可能会漏了一部分事件的触发
if isinstance(event, qw.QGraphicsSceneMouseEvent):
if event.type() == 155:
obj.mouseMoveEvent(event)
elif event.type() == 156:
obj.mousePressEvent(event)
elif event.type() == 157:
obj.mouseReleaseEvent(event)
elif event.type() == 158:
obj.mouseDoubleClickEvent(event)
else:
print("other ", event.type())
elif isinstance(event, qw.QGraphicsSceneContextMenuEvent):
print(type(obj), type(event), event.type())
obj.contextMenuEvent(event)
else:
obj._sceneEvent(event)
return True
assert not hasattr(obj, "_mousePressEvent")
obj._mousePressEvent = obj.mousePressEvent
obj.mousePressEvent = mousePressEvent
assert not hasattr(obj, "_mouseReleaseEvent")
obj._mouseReleaseEvent = obj.mouseReleaseEvent
obj.mouseReleaseEvent = mouseReleaseEvent
assert not hasattr(obj, "_sceneEvent")
obj._sceneEvent = obj.sceneEvent
obj.sceneEvent = sceneEvent
return obj
if __name__ == "__main__":
def make_items(obj_wraper: Callable = None):
flag1 = qw.QGraphicsItem.GraphicsItemFlag.ItemIsMovable
flag2 = qw.QGraphicsItem.GraphicsItemFlag.ItemIsSelectable
scene = qw.QGraphicsScene()
scene.setBackgroundBrush(qg.QColor(qg.QColor().red()))
pen = qg.QPen()
pen.setColor(qg.QColor(0, 160, 230))
pen.setWidth(10)
m_rectItem = qw.QGraphicsRectItem()
m_rectItem.setRect(0, 0, 80, 80)
m_rectItem.setPen(pen)
m_rectItem.setBrush(qg.QBrush(qg.QColor(255, 0, 255)))
m_rectItem.setFlag(flag1)
m_rectItem.setFlag(flag2)
bt = qw.QPushButton()
bt_p = qw.QGraphicsProxyWidget()
bt_p.setWidget(bt)
def on_bt_click(event):
print("clicked")
bt.clicked.connect(on_bt_click)
m_lineItem = qw.QGraphicsLineItem()
m_lineItem.setLine(qc.QLineF(0, 0, 100, 100))
m_lineItem.setPen(pen)
m_lineItem.setFlag(flag1)
m_lineItem.setFlag(flag2)
m_pathItem = qw.QGraphicsPathItem()
path = qg.QPainterPath()
path.moveTo(90, 50)
for i in range(1, 5):
path.lineTo(
50 + 40 * np.cos(0.8 * i * np.pi), 50 + 40 * np.sin(0.8 * i * np.pi)
)
path.closeSubpath()
m_pathItem.setPath(path)
m_pathItem.setPen(pen)
m_pathItem.setFlag(flag1)
m_pathItem.setFlag(flag2)
m_polygonItem = qw.QGraphicsPolygonItem()
polygon = qg.QPolygonF()
polygon.append(qc.QPointF(-100.0, -150.0))
polygon.append(qc.QPointF(-120.0, 150.0))
polygon.append(qc.QPointF(320.0, 160.0))
polygon.append(qc.QPointF(220.0, -140.0))
m_polygonItem.setPolygon(polygon)
m_polygonItem.setPen(pen)
m_polygonItem.setFlag(flag1)
m_polygonItem.setFlag(flag2)
gp = qw.QGraphicsItemGroup()
gp.setFlag(flag1)
gp.setFlag(flag2)
if obj_wraper:
m_rectItem = obj_wraper(m_rectItem)
bt_p = obj_wraper(bt_p)
m_polygonItem = obj_wraper(m_polygonItem)
m_lineItem = obj_wraper(m_lineItem)
m_pathItem = obj_wraper(m_pathItem)
gp.addToGroup(m_rectItem)
gp.addToGroup(bt_p)
scene.addItem(m_polygonItem)
scene.addItem(m_lineItem)
scene.addItem(m_pathItem)
scene.addItem(gp)
v = qw.QGraphicsView()
v.setBackgroundBrush(qg.QBrush(qg.QColor(75, 225, 200)))
v.setScene(scene)
v.resize(1027, 768)
return v
def test1():
# 直接更改类的函数来重载 event
app = qw.QApplication(sys.argv)
change_type_event() # 重载
v = make_items()
v.show()
r = app.exec_()
sys.exit(r)
def test2():
# 更改实例的函数来重载 event
app = qw.QApplication(sys.argv)
v = make_items(change_event_item)
v.show()
r = app.exec_()
sys.exit(r)
# 两个 test 是两种方式, 只能按一种方式重载
# test1()
test2()
