如何使选定的 qgraphicsitem 的边界矩形自动显示？
How to make the bounding rect of a selected qgraphicsitem show automatically?
我在 SO 中通过 @serge_gubenko 找到了这个例子。
Moving a QGraphicsItem around a central point in PyQt4
然后我做了一些修改以结束：
如果我运行示例 (Moving a QGraphicsItem around a central point in PyQt4) 并单击图形项，它会自动显示一个虚线框，表明它已被选中。我准备了图片来展示效果，但由于我的声誉不高，我还不允许上传这些 ;)
对我来说，虚线框旁的 "is selected indication" 似乎是自动出现的。
在我修改的示例 () 中，这并没有发生，我不明白为什么？
您使用了QtGui.QGraphicsItem，所以您定义了boundingRect 和paint 方法，其中您使用了painter drawEllipse 方法。在您找到的第一个示例中，class 直接使用 QtGui.QGraphicsEllipseItem 并且它做了所有不同的事情，因为那些方法已经定义了。顺便说一句，我没有找到为什么 boundingRect 没有在你的案例中绘制。
这是一个工作示例，它有自己的 drawFocusRect 方法。
焦点有两种表示方式：
1）通过点击Qgraphicsitem，然后绘制边界矩形。
2) 将鼠标悬停在项目上。触发时 hoverEnterEvent the pen style is changed to DotLine converting back to SolidLine when the hoverLeaveEvent 被触发。
#!d:/python27/python -u
import sys
from PyQt4 import QtGui, QtCore
class GraphicsItem(QtGui.QGraphicsItem):
"""
From the QT docs:
To write your own graphics item, you first create a subclass
of QGraphicsItem, and then start by implementing its two pure
virtual public functions: boundingRect(), which returns an estimate
of the area painted by the item, and paint(),
which implements the actual painting.
"""
# call constructor of GraphicsItem
def __init__(self, rect, pen, brush, tooltip='No tip here', parent=None):
# call constructor of QGraphicsItem
super(GraphicsItem, self).__init__()
self.setFlag(QtGui.QGraphicsItem.ItemIsMovable, True)
self.setFlag(QtGui.QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QtGui.QGraphicsItem.ItemIsFocusable, True)
self.setAcceptsHoverEvents(True)
self.pen = pen
pw = self.pen.widthF()
self.brush = QtGui.QBrush(QtCore.Qt.blue)
self.brush = brush
self.setToolTip(tooltip)
self.parent = parent
self.rect = QtCore.QRectF(rect[0], rect[1], rect[2], rect[3])
self.focusrect = QtCore.QRectF(rect[0]-pw/2, rect[1]-pw/2,
rect[2]+pw, rect[3]+pw)
def mouseMoveEvent(self, event):
# move object
QtGui.QGraphicsItem.mouseMoveEvent(self, event)
def mousePressEvent(self, event):
# select object
# set item as topmost in stack
self.setZValue(self.parent.scene.items()[0].zValue() + 1)
self.setSelected(True)
QtGui.QGraphicsItem.mousePressEvent(self, event)
def boundingRect(self):
return self.rect
def paint(self, painter, option, widget):
painter.setBrush(self.brush)
painter.setPen(self.pen)
painter.drawEllipse(self.rect)
if self.isSelected():
self.drawFocusRect(painter)
def drawFocusRect(self, painter):
self.focusbrush = QtGui.QBrush()
self.focuspen = QtGui.QPen(QtCore.Qt.DotLine)
self.focuspen.setColor(QtCore.Qt.black)
self.focuspen.setWidthF(1.5)
painter.setBrush(self.focusbrush)
painter.setPen(self.focuspen)
painter.drawRect(self.focusrect)
def hoverEnterEvent(self, event):
self.pen.setStyle(QtCore.Qt.DotLine)
QtGui.QGraphicsItem.hoverEnterEvent(self, event)
def hoverLeaveEvent(self, event):
self.pen.setStyle(QtCore.Qt.SolidLine)
QtGui.QGraphicsItem.hoverLeaveEvent(self, event)
class MyMainWindow(QtGui.QMainWindow):
# call constructor of MyMainWindow
def __init__(self, parent=None):
# call constructor of QMainWindow
super(MyMainWindow, self).__init__(parent)
w = 1000
h = 800
self.scene = QtGui.QGraphicsScene(-w/2, -h/2, w, h)
self.view = QtGui.QGraphicsView()
# set QGraphicsView attributes
self.view.setRenderHints(QtGui.QPainter.Antialiasing |
QtGui.QPainter.HighQualityAntialiasing)
self.view.setViewportUpdateMode(QtGui.QGraphicsView.FullViewportUpdate)
self.view.setScene(self.scene)
# set central widget for the application
self.setCentralWidget(self.view)
# add items to the scene
self.addGraphicsItem((0, 0, 250, 250), 8.0, (255, 0, 0), (0, 0, 255), 'My first item')
self.addGraphicsItem((-250, -250, 300, 200), 4.0, (0, 0, 0), (255, 0, 100), 'My 2nd item')
self.addGraphicsItem((200, -200, 200, 200), 10.0, (0, 0, 255), (0, 255, 100), 'My 3rd item')
def addGraphicsItem(self, rect, pw, pc, bc, tooltip):
pen = QtGui.QPen(QtCore.Qt.SolidLine)
pen.setColor(QtGui.QColor(pc[0], pc[1], pc[2], 255))
pen.setWidth(pw)
brush = QtGui.QBrush(QtGui.QColor(bc[0], bc[1], bc[2], 255))
item = GraphicsItem(rect, pen, brush, tooltip, self)
self.scene.addItem(item)
def mousePressEvent(self, event):
#print 'from MainWindow'
pass
def keyPressEvent(self, event):
key = event.key()
if key == QtCore.Qt.Key_Escape:
sys.exit(QtGui.qApp.quit())
else:
super(GraphicsView, self).keyPressEvent(event)
def main():
app = QtGui.QApplication(sys.argv)
form = MyMainWindow()
form.setGeometry(700, 100, 1050, 850)
form.show()
app.exec_()
if __name__ == '__main__':
main()
针对 PyQt5 更新
import sys
from PyQt5 import QtGui, QtCore, QtWidgets
class GraphicsItem(QtWidgets.QGraphicsItem):
"""
From the QT docs:
To write your own graphics item, you first create a subclass
of QGraphicsItem, and then start by implementing its two pure
virtual public functions: boundingRect(), which returns an estimate
of the area painted by the item, and paint(),
which implements the actual painting.
"""
# call constructor of GraphicsItem
def __init__(self, rect, pen, brush, tooltip='No tip here', parent=None):
# call constructor of QGraphicsItem
super(GraphicsItem, self).__init__()
self.setFlag(QtWidgets.QGraphicsItem.ItemIsMovable, True)
self.setFlag(QtWidgets.QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QtWidgets.QGraphicsItem.ItemIsFocusable, True)
self.setAcceptHoverEvents(True)
self.pen = pen
pw = self.pen.widthF()
self.brush = QtGui.QBrush(QtCore.Qt.blue)
self.brush = brush
self.setToolTip(tooltip)
self.parent = parent
self.rect = QtCore.QRectF(rect[0], rect[1], rect[2], rect[3])
self.focusrect = QtCore.QRectF(rect[0]-pw/2, rect[1]-pw/2,
rect[2]+pw, rect[3]+pw)
def mouseMoveEvent(self, event):
# move object
QtWidgets.QGraphicsItem.mouseMoveEvent(self, event)
def mousePressEvent(self, event):
# select object
# set item as topmost in stack
self.setZValue(self.parent.scene.items()[0].zValue() + 1)
self.setSelected(True)
QtWidgets.QGraphicsItem.mousePressEvent(self, event)
def boundingRect(self):
return self.rect
def paint(self, painter, option, widget=None):
painter.setBrush(self.brush)
painter.setPen(self.pen)
painter.drawEllipse(self.rect)
if self.isSelected():
self.drawFocusRect(painter)
def drawFocusRect(self, painter):
self.focusbrush = QtGui.QBrush()
self.focuspen = QtGui.QPen(QtCore.Qt.DotLine)
self.focuspen.setColor(QtCore.Qt.black)
self.focuspen.setWidthF(1.5)
painter.setBrush(self.focusbrush)
painter.setPen(self.focuspen)
painter.drawRect(self.focusrect)
def hoverEnterEvent(self, event):
self.pen.setStyle(QtCore.Qt.DotLine)
QtWidgets.QGraphicsItem.hoverEnterEvent(self, event)
def hoverLeaveEvent(self, event):
self.pen.setStyle(QtCore.Qt.SolidLine)
QtWidgets.QGraphicsItem.hoverLeaveEvent(self, event)
class MyMainWindow(QtWidgets.QMainWindow):
# call constructor of MyMainWindow
def __init__(self, parent=None):
# call constructor of QMainWindow
super(MyMainWindow, self).__init__(parent)
w = 1000
h = 800
self.scene = QtWidgets.QGraphicsScene(-w/2, -h/2, w, h)
self.view = QtWidgets.QGraphicsView()
# set QGraphicsView attributes
self.view.setRenderHints(QtGui.QPainter.Antialiasing |
QtGui.QPainter.HighQualityAntialiasing)
self.view.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate)
self.view.setScene(self.scene)
# set central widget for the application
self.setCentralWidget(self.view)
# add items to the scene
self.addGraphicsItem((0, 0, 250, 250), 8.0, (255, 0, 0), (0, 0, 255), 'My first item')
self.addGraphicsItem((-250, -250, 300, 200), 4.0, (0, 0, 0), (255, 0, 100), 'My 2nd item')
self.addGraphicsItem((200, -200, 200, 200), 10.0, (0, 0, 255), (0, 255, 100), 'My 3rd item')
def addGraphicsItem(self, rect, pw, pc, bc, tooltip):
pen = QtGui.QPen(QtCore.Qt.SolidLine)
pen.setColor(QtGui.QColor(pc[0], pc[1], pc[2], 255))
pen.setWidth(pw)
brush = QtGui.QBrush(QtGui.QColor(bc[0], bc[1], bc[2], 255))
item = GraphicsItem(rect, pen, brush, tooltip, self)
self.scene.addItem(item)
def mousePressEvent(self, event):
#print 'from MainWindow'
pass
def main():
app = QtWidgets.QApplication(sys.argv)
form = MyMainWindow()
form.setGeometry(700, 100, 1050, 850)
form.show()
app.exec_()
if __name__ == '__main__':
main()
我在 SO 中通过 @serge_gubenko 找到了这个例子。 Moving a QGraphicsItem around a central point in PyQt4
然后我做了一些修改以结束：
如果我运行示例 (Moving a QGraphicsItem around a central point in PyQt4) 并单击图形项，它会自动显示一个虚线框，表明它已被选中。我准备了图片来展示效果，但由于我的声誉不高，我还不允许上传这些 ;)
对我来说，虚线框旁的 "is selected indication" 似乎是自动出现的。
在我修改的示例 (
您使用了QtGui.QGraphicsItem，所以您定义了boundingRect 和paint 方法，其中您使用了painter drawEllipse 方法。在您找到的第一个示例中，class 直接使用 QtGui.QGraphicsEllipseItem 并且它做了所有不同的事情，因为那些方法已经定义了。顺便说一句，我没有找到为什么 boundingRect 没有在你的案例中绘制。
这是一个工作示例，它有自己的 drawFocusRect 方法。
焦点有两种表示方式：
1）通过点击Qgraphicsitem，然后绘制边界矩形。
2) 将鼠标悬停在项目上。触发时 hoverEnterEvent the pen style is changed to DotLine converting back to SolidLine when the hoverLeaveEvent 被触发。
#!d:/python27/python -u
import sys
from PyQt4 import QtGui, QtCore
class GraphicsItem(QtGui.QGraphicsItem):
"""
From the QT docs:
To write your own graphics item, you first create a subclass
of QGraphicsItem, and then start by implementing its two pure
virtual public functions: boundingRect(), which returns an estimate
of the area painted by the item, and paint(),
which implements the actual painting.
"""
# call constructor of GraphicsItem
def __init__(self, rect, pen, brush, tooltip='No tip here', parent=None):
# call constructor of QGraphicsItem
super(GraphicsItem, self).__init__()
self.setFlag(QtGui.QGraphicsItem.ItemIsMovable, True)
self.setFlag(QtGui.QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QtGui.QGraphicsItem.ItemIsFocusable, True)
self.setAcceptsHoverEvents(True)
self.pen = pen
pw = self.pen.widthF()
self.brush = QtGui.QBrush(QtCore.Qt.blue)
self.brush = brush
self.setToolTip(tooltip)
self.parent = parent
self.rect = QtCore.QRectF(rect[0], rect[1], rect[2], rect[3])
self.focusrect = QtCore.QRectF(rect[0]-pw/2, rect[1]-pw/2,
rect[2]+pw, rect[3]+pw)
def mouseMoveEvent(self, event):
# move object
QtGui.QGraphicsItem.mouseMoveEvent(self, event)
def mousePressEvent(self, event):
# select object
# set item as topmost in stack
self.setZValue(self.parent.scene.items()[0].zValue() + 1)
self.setSelected(True)
QtGui.QGraphicsItem.mousePressEvent(self, event)
def boundingRect(self):
return self.rect
def paint(self, painter, option, widget):
painter.setBrush(self.brush)
painter.setPen(self.pen)
painter.drawEllipse(self.rect)
if self.isSelected():
self.drawFocusRect(painter)
def drawFocusRect(self, painter):
self.focusbrush = QtGui.QBrush()
self.focuspen = QtGui.QPen(QtCore.Qt.DotLine)
self.focuspen.setColor(QtCore.Qt.black)
self.focuspen.setWidthF(1.5)
painter.setBrush(self.focusbrush)
painter.setPen(self.focuspen)
painter.drawRect(self.focusrect)
def hoverEnterEvent(self, event):
self.pen.setStyle(QtCore.Qt.DotLine)
QtGui.QGraphicsItem.hoverEnterEvent(self, event)
def hoverLeaveEvent(self, event):
self.pen.setStyle(QtCore.Qt.SolidLine)
QtGui.QGraphicsItem.hoverLeaveEvent(self, event)
class MyMainWindow(QtGui.QMainWindow):
# call constructor of MyMainWindow
def __init__(self, parent=None):
# call constructor of QMainWindow
super(MyMainWindow, self).__init__(parent)
w = 1000
h = 800
self.scene = QtGui.QGraphicsScene(-w/2, -h/2, w, h)
self.view = QtGui.QGraphicsView()
# set QGraphicsView attributes
self.view.setRenderHints(QtGui.QPainter.Antialiasing |
QtGui.QPainter.HighQualityAntialiasing)
self.view.setViewportUpdateMode(QtGui.QGraphicsView.FullViewportUpdate)
self.view.setScene(self.scene)
# set central widget for the application
self.setCentralWidget(self.view)
# add items to the scene
self.addGraphicsItem((0, 0, 250, 250), 8.0, (255, 0, 0), (0, 0, 255), 'My first item')
self.addGraphicsItem((-250, -250, 300, 200), 4.0, (0, 0, 0), (255, 0, 100), 'My 2nd item')
self.addGraphicsItem((200, -200, 200, 200), 10.0, (0, 0, 255), (0, 255, 100), 'My 3rd item')
def addGraphicsItem(self, rect, pw, pc, bc, tooltip):
pen = QtGui.QPen(QtCore.Qt.SolidLine)
pen.setColor(QtGui.QColor(pc[0], pc[1], pc[2], 255))
pen.setWidth(pw)
brush = QtGui.QBrush(QtGui.QColor(bc[0], bc[1], bc[2], 255))
item = GraphicsItem(rect, pen, brush, tooltip, self)
self.scene.addItem(item)
def mousePressEvent(self, event):
#print 'from MainWindow'
pass
def keyPressEvent(self, event):
key = event.key()
if key == QtCore.Qt.Key_Escape:
sys.exit(QtGui.qApp.quit())
else:
super(GraphicsView, self).keyPressEvent(event)
def main():
app = QtGui.QApplication(sys.argv)
form = MyMainWindow()
form.setGeometry(700, 100, 1050, 850)
form.show()
app.exec_()
if __name__ == '__main__':
main()
针对 PyQt5 更新
import sys
from PyQt5 import QtGui, QtCore, QtWidgets
class GraphicsItem(QtWidgets.QGraphicsItem):
"""
From the QT docs:
To write your own graphics item, you first create a subclass
of QGraphicsItem, and then start by implementing its two pure
virtual public functions: boundingRect(), which returns an estimate
of the area painted by the item, and paint(),
which implements the actual painting.
"""
# call constructor of GraphicsItem
def __init__(self, rect, pen, brush, tooltip='No tip here', parent=None):
# call constructor of QGraphicsItem
super(GraphicsItem, self).__init__()
self.setFlag(QtWidgets.QGraphicsItem.ItemIsMovable, True)
self.setFlag(QtWidgets.QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QtWidgets.QGraphicsItem.ItemIsFocusable, True)
self.setAcceptHoverEvents(True)
self.pen = pen
pw = self.pen.widthF()
self.brush = QtGui.QBrush(QtCore.Qt.blue)
self.brush = brush
self.setToolTip(tooltip)
self.parent = parent
self.rect = QtCore.QRectF(rect[0], rect[1], rect[2], rect[3])
self.focusrect = QtCore.QRectF(rect[0]-pw/2, rect[1]-pw/2,
rect[2]+pw, rect[3]+pw)
def mouseMoveEvent(self, event):
# move object
QtWidgets.QGraphicsItem.mouseMoveEvent(self, event)
def mousePressEvent(self, event):
# select object
# set item as topmost in stack
self.setZValue(self.parent.scene.items()[0].zValue() + 1)
self.setSelected(True)
QtWidgets.QGraphicsItem.mousePressEvent(self, event)
def boundingRect(self):
return self.rect
def paint(self, painter, option, widget=None):
painter.setBrush(self.brush)
painter.setPen(self.pen)
painter.drawEllipse(self.rect)
if self.isSelected():
self.drawFocusRect(painter)
def drawFocusRect(self, painter):
self.focusbrush = QtGui.QBrush()
self.focuspen = QtGui.QPen(QtCore.Qt.DotLine)
self.focuspen.setColor(QtCore.Qt.black)
self.focuspen.setWidthF(1.5)
painter.setBrush(self.focusbrush)
painter.setPen(self.focuspen)
painter.drawRect(self.focusrect)
def hoverEnterEvent(self, event):
self.pen.setStyle(QtCore.Qt.DotLine)
QtWidgets.QGraphicsItem.hoverEnterEvent(self, event)
def hoverLeaveEvent(self, event):
self.pen.setStyle(QtCore.Qt.SolidLine)
QtWidgets.QGraphicsItem.hoverLeaveEvent(self, event)
class MyMainWindow(QtWidgets.QMainWindow):
# call constructor of MyMainWindow
def __init__(self, parent=None):
# call constructor of QMainWindow
super(MyMainWindow, self).__init__(parent)
w = 1000
h = 800
self.scene = QtWidgets.QGraphicsScene(-w/2, -h/2, w, h)
self.view = QtWidgets.QGraphicsView()
# set QGraphicsView attributes
self.view.setRenderHints(QtGui.QPainter.Antialiasing |
QtGui.QPainter.HighQualityAntialiasing)
self.view.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate)
self.view.setScene(self.scene)
# set central widget for the application
self.setCentralWidget(self.view)
# add items to the scene
self.addGraphicsItem((0, 0, 250, 250), 8.0, (255, 0, 0), (0, 0, 255), 'My first item')
self.addGraphicsItem((-250, -250, 300, 200), 4.0, (0, 0, 0), (255, 0, 100), 'My 2nd item')
self.addGraphicsItem((200, -200, 200, 200), 10.0, (0, 0, 255), (0, 255, 100), 'My 3rd item')
def addGraphicsItem(self, rect, pw, pc, bc, tooltip):
pen = QtGui.QPen(QtCore.Qt.SolidLine)
pen.setColor(QtGui.QColor(pc[0], pc[1], pc[2], 255))
pen.setWidth(pw)
brush = QtGui.QBrush(QtGui.QColor(bc[0], bc[1], bc[2], 255))
item = GraphicsItem(rect, pen, brush, tooltip, self)
self.scene.addItem(item)
def mousePressEvent(self, event):
#print 'from MainWindow'
pass
def main():
app = QtWidgets.QApplication(sys.argv)
form = MyMainWindow()
form.setGeometry(700, 100, 1050, 850)
form.show()
app.exec_()
if __name__ == '__main__':
main()