Python 在pyqt中使用sceneEventFilter捕获悬停事件
我在图形场景中有用户可调整的注释。注释的大小/旋转是通过围绕注释拖动矩形的角来处理的。我使用的是一个自定义矩形（而不是boundingRect），因此它遵循父注释的旋转。控制角由两个椭圆标记，其父对象是rect，因此rect/椭圆/注释的变换是无缝的 我想检测光标何时在某个角上，它是哪个角，以及精确的坐标。对于这个任务，我似乎应该使用sceneEventFilter用父rect过滤hoverevents 我尝试过无数种实现sceneEventFilter的方法，但都没有效果。所有事件直接进入hoverEnterEvent函数。我只找到了一些类似这样的示例代码，但我完全被卡住了。顺便说一句，在过去的3个月里，我完全自学了Python和QT，所以请容忍我。我肯定我错过了一些非常基本的东西。代码是一个带有两个省略号的简化gui。我们希望在sceneEventFilter中捕获事件，但总是转到hoverEnterEventPython 在pyqt中使用sceneEventFilter捕获悬停事件,python,pyqt,pyqt5,pyqtgraph,eventfilter,Python,Pyqt,Pyqt5,Pyqtgraph,Eventfilter,我在图形场景中有用户可调整的注释。注释的大小/旋转是通过围绕注释拖动矩形的角来处理的。我使用的是一个自定义矩形（而不是boundingRect），因此它遵循父注释的旋转。控制角由两个椭圆标记，其父对象是rect，因此rect/椭圆/注释的变换是无缝的 我想检测光标何时在某个角上，它是哪个角，以及精确的坐标。对于这个任务，我似乎应该使用sceneEventFilter用父rect过滤hoverevents 我尝试过无数种实现sceneEventFilter的方法，但都没有效果。所有事件直接进入ho
from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg
from PyQt5.QtWidgets import QGraphicsScene, QGraphicsView, QGraphicsItem
import sys
class myHandle(QtGui.QGraphicsEllipseItem):
def __init__(self, parent = None):
super(myHandle, self).__init__(parent)
def addTheHandle(self, h_parent = 'null', kind = 'null'):
handle_w = 40
if kind == 'scaling handle':
handle_x = h_parent.boundingRect().topRight().x() - handle_w/2
handle_y = h_parent.boundingRect().topRight().y() - handle_w/2
if kind == 'rotation handle':
handle_x = h_parent.boundingRect().topLeft().x() - handle_w/2
handle_y = h_parent.boundingRect().topLeft().y() - handle_w/2
the_handle = QtGui.QGraphicsEllipseItem(QtCore.QRectF(handle_x, handle_y, handle_w, handle_w))
the_handle.setPen(QtGui.QPen(QtGui.QColor(255, 100, 0), 3))
the_handle.setParentItem(h_parent)
the_handle.setAcceptHoverEvents(True)
the_handle.kind = kind
return the_handle
class myRect(QtGui.QGraphicsRectItem):
def __init__(self, parent = None):
super(myRect, self).__init__(parent)
def rectThing(self, boundingrectangle):
self.setAcceptHoverEvents(True)
self.setRect(boundingrectangle)
mh = myHandle()
rotation_handle = mh.addTheHandle(h_parent = self, kind = 'rotation handle')
scaling_handle = mh.addTheHandle(h_parent = self, kind = 'scaling handle')
self.installSceneEventFilter(rotation_handle)
self.installSceneEventFilter(scaling_handle)
return self, rotation_handle, scaling_handle
def sceneEventFilter(self, event):
print('scene ev filter')
return False
def hoverEnterEvent(self, event):
print('hover enter event')
class Basic(QtGui.QMainWindow):
def __init__(self):
super(Basic, self).__init__()
self.initUI()
def eventFilter(self, source, event):
return QtGui.QMainWindow.eventFilter(self, source, event)
def exit_the_program(self):
pg.exit()
def initUI(self):
self.resize(300, 300)
self.centralwidget = QtGui.QWidget()
self.setCentralWidget(self.centralwidget)
self.h_layout = QtGui.QHBoxLayout(self.centralwidget)
self.exit_program = QtGui.QPushButton('Exit')
self.exit_program.clicked.connect(self.exit_the_program)
self.h_layout.addWidget(self.exit_program)
self.this_scene = QGraphicsScene()
self.this_view = QGraphicsView(self.this_scene)
self.this_view.setMouseTracking(True)
self.this_view.viewport().installEventFilter(self)
self.h_layout.addWidget(self.this_view)
self.circle = self.this_scene.addEllipse(QtCore.QRectF(40, 40, 65, 65), QtGui.QPen(QtCore.Qt.black))
mr = myRect()
the_rect, rotation_handle, scaling_handle = mr.rectThing(self.circle.boundingRect())
the_rect.setPen(QtGui.QPen(QtCore.Qt.black))
the_rect.setParentItem(self.circle)
self.this_scene.addItem(the_rect)
self.this_scene.addItem(rotation_handle)
self.this_scene.addItem(scaling_handle)
def main():
app = QtGui.QApplication([])
main = Basic()
main.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
主要问题是您正在矩形上安装目标项的事件过滤器：矩形的事件过滤器将永远不会接收任何内容。此外，
sceneEventFilter rotation_handle.installSceneEventFilter(self)
scaling_handle.installSceneEventFilter(self)
from math import sqrt
# ...
class myRect(QtGui.QGraphicsRectItem):
def __init__(self, parent):
super(myRect, self).__init__(parent)
self.setRect(parent.boundingRect())
# rotation is usually based on the center of an object
self.parentItem().setTransformOriginPoint(self.parentItem().rect().center())
# a rectangle that has a center at (0, 0)
handleRect = QtCore.QRectF(-20, -20, 40, 40)
self.rotation_handle = QtGui.QGraphicsEllipseItem(handleRect, self)
self.scaling_handle = QtGui.QGraphicsEllipseItem(handleRect, self)
# position the handles by centering them at the right corners
self.rotation_handle.setPos(self.rect().topLeft())
self.scaling_handle.setPos(self.rect().topRight())
for source in (self.rotation_handle, self.scaling_handle):
# install the *self* event filter on the handles
source.installSceneEventFilter(self)
source.setPen(QtGui.QPen(QtGui.QColor(255, 100, 0), 3))
def sceneEventFilter(self, source, event):
if event.type() == QtCore.QEvent.GraphicsSceneMouseMove:
# map the handle event position to the ellipse parent item; we could
# also map to "self", but using the parent is more consistent
localPos = self.parentItem().mapFromItem(source, event.pos())
if source == self.rotation_handle:
# create a temporary line to get the rotation angle
line = QtCore.QLineF(self.boundingRect().center(), localPos)
# add the current rotation to the angle between the center and the
# top left corner, then subtract the new line angle
self.parentItem().setRotation(135 + self.parentItem().rotation() - line.angle())
# note that I'm assuming that the ellipse is a circle, so the top
# left angle will always be at 135°; if it's not a circle, the
# rect width and height won't match and the angle will be
# different, so you'll need to compute that
# parentRect = self.parentItem().rect()
# oldLine = QtCore.QLineF(parentRect.center(), parentRect.topLeft())
# self.parentItem().setRotation(
# oldLine.angle() + self.parentItem().rotation() - line.angle())
elif source == self.scaling_handle:
# still assuming a perfect circle, so the rectangle is a square;
# the line from the center to the top right corner is used to
# compute the square side size, which is the double of a
# right-triangle cathetus where the hypotenuse is the line
# between the center and any of its corners;
# if the ellipse is not a perfect circle, you'll have to
# compute both of the catheti
hyp = QtCore.QLineF(self.boundingRect().center(), localPos)
size = sqrt(2) * hyp.length()
rect = QtCore.QRectF(0, 0, size, size)
rect.moveCenter(self.rect().center())
self.parentItem().setRect(rect)
self.setRect(rect)
# update the positions of both handles
self.rotation_handle.setPos(self.rect().topLeft())
self.scaling_handle.setPos(self.rect().topRight())
return True
elif event.type() == QtCore.QEvent.GraphicsSceneMousePress:
# return True to the press event (which is almost as setting it as
# accepted, so that it won't be processed further more by the scene,
# allowing the sceneEventFilter to capture the following mouseMove
# events that the watched graphics items will receive
return True
return super(myRect, self).sceneEventFilter(source, event)
class Basic(QtGui.QMainWindow):
# ...
def initUI(self):
# ...
self.circle = self.this_scene.addEllipse(QtCore.QRectF(40, 40, 65, 65), QtGui.QPen(QtCore.Qt.black))
mr = myRect(self.circle)
self.this_scene.addItem(mr)
主要问题是您正在矩形上安装目标项的事件过滤器：矩形的事件过滤器将永远不会接收任何内容。此外，
sceneEventFilter rotation_handle.installSceneEventFilter(self)
scaling_handle.installSceneEventFilter(self)
from math import sqrt
# ...
class myRect(QtGui.QGraphicsRectItem):
def __init__(self, parent):
super(myRect, self).__init__(parent)
self.setRect(parent.boundingRect())
# rotation is usually based on the center of an object
self.parentItem().setTransformOriginPoint(self.parentItem().rect().center())
# a rectangle that has a center at (0, 0)
handleRect = QtCore.QRectF(-20, -20, 40, 40)
self.rotation_handle = QtGui.QGraphicsEllipseItem(handleRect, self)
self.scaling_handle = QtGui.QGraphicsEllipseItem(handleRect, self)
# position the handles by centering them at the right corners
self.rotation_handle.setPos(self.rect().topLeft())
self.scaling_handle.setPos(self.rect().topRight())
for source in (self.rotation_handle, self.scaling_handle):
# install the *self* event filter on the handles
source.installSceneEventFilter(self)
source.setPen(QtGui.QPen(QtGui.QColor(255, 100, 0), 3))
def sceneEventFilter(self, source, event):
if event.type() == QtCore.QEvent.GraphicsSceneMouseMove:
# map the handle event position to the ellipse parent item; we could
# also map to "self", but using the parent is more consistent
localPos = self.parentItem().mapFromItem(source, event.pos())
if source == self.rotation_handle:
# create a temporary line to get the rotation angle
line = QtCore.QLineF(self.boundingRect().center(), localPos)
# add the current rotation to the angle between the center and the
# top left corner, then subtract the new line angle
self.parentItem().setRotation(135 + self.parentItem().rotation() - line.angle())
# note that I'm assuming that the ellipse is a circle, so the top
# left angle will always be at 135°; if it's not a circle, the
# rect width and height won't match and the angle will be
# different, so you'll need to compute that
# parentRect = self.parentItem().rect()
# oldLine = QtCore.QLineF(parentRect.center(), parentRect.topLeft())
# self.parentItem().setRotation(
# oldLine.angle() + self.parentItem().rotation() - line.angle())
elif source == self.scaling_handle:
# still assuming a perfect circle, so the rectangle is a square;
# the line from the center to the top right corner is used to
# compute the square side size, which is the double of a
# right-triangle cathetus where the hypotenuse is the line
# between the center and any of its corners;
# if the ellipse is not a perfect circle, you'll have to
# compute both of the catheti
hyp = QtCore.QLineF(self.boundingRect().center(), localPos)
size = sqrt(2) * hyp.length()
rect = QtCore.QRectF(0, 0, size, size)
rect.moveCenter(self.rect().center())
self.parentItem().setRect(rect)
self.setRect(rect)
# update the positions of both handles
self.rotation_handle.setPos(self.rect().topLeft())
self.scaling_handle.setPos(self.rect().topRight())
return True
elif event.type() == QtCore.QEvent.GraphicsSceneMousePress:
# return True to the press event (which is almost as setting it as
# accepted, so that it won't be processed further more by the scene,
# allowing the sceneEventFilter to capture the following mouseMove
# events that the watched graphics items will receive
return True
return super(myRect, self).sceneEventFilter(source, event)
class Basic(QtGui.QMainWindow):
# ...
def initUI(self):
# ...
self.circle = self.this_scene.addEllipse(QtCore.QRectF(40, 40, 65, 65), QtGui.QPen(QtCore.Qt.black))
mr = myRect(self.circle)
self.this_scene.addItem(mr)