如何将多个对象添加到场景中？
How to add multiple objects to the scene?
已创建一组可用于调整形状大小的手柄。
通过跟踪手柄位置的变化，您可以计算形状的新几何形状。
我无法将多个对象添加到场景中。
import sys
from PyQt5.QtCore import Qt, QRectF, QPointF
from PyQt5.QtGui import QBrush, QPainterPath, QPainter, QColor, QPen, QPixmap
from PyQt5.QtWidgets import QGraphicsRectItem, QApplication, QGraphicsView, QGraphicsScene, QGraphicsItem
class GraphicsRectItem(QGraphicsRectItem):
handleTopLeft = 1
handleTopMiddle = 2
handleTopRight = 3
handleMiddleLeft = 4
handleMiddleRight = 5
handleBottomLeft = 6
handleBottomMiddle = 7
handleBottomRight = 8
handleSize = +8.0
handleSpace = -4.0
handleCursors = {
handleTopLeft: Qt.SizeFDiagCursor,
handleTopMiddle: Qt.SizeVerCursor,
handleTopRight: Qt.SizeBDiagCursor,
handleMiddleLeft: Qt.SizeHorCursor,
handleMiddleRight: Qt.SizeHorCursor,
handleBottomLeft: Qt.SizeBDiagCursor,
handleBottomMiddle: Qt.SizeVerCursor,
handleBottomRight: Qt.SizeFDiagCursor,
}
def __init__(self, *args):
"""
Initialize the shape.
"""
super().__init__(*args)
self.handles = {}
self.handleSelected = None
self.mousePressPos = None
self.mousePressRect = None
self.setAcceptHoverEvents(True)
self.setFlag(QGraphicsItem.ItemIsMovable, True)
self.setFlag(QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges, True)
self.setFlag(QGraphicsItem.ItemIsFocusable, True)
self.updateHandlesPos()
def handleAt(self, point):
"""
Returns the resize handle below the given point.
"""
for k, v, in self.handles.items():
if v.contains(point):
return k
return None
def hoverMoveEvent(self, moveEvent):
"""
Executed when the mouse moves over the shape (NOT PRESSED).
"""
if self.isSelected():
handle = self.handleAt(moveEvent.pos())
cursor = Qt.ArrowCursor if handle is None else self.handleCursors[handle]
self.setCursor(cursor)
super().hoverMoveEvent(moveEvent)
def hoverLeaveEvent(self, moveEvent):
"""
Executed when the mouse leaves the shape (NOT PRESSED).
"""
self.setCursor(Qt.ArrowCursor)
super().hoverLeaveEvent(moveEvent)
def mousePressEvent(self, mouseEvent):
"""
Executed when the mouse is pressed on the item.
"""
self.handleSelected = self.handleAt(mouseEvent.pos())
if self.handleSelected:
self.mousePressPos = mouseEvent.pos()
self.mousePressRect = self.boundingRect()
super().mousePressEvent(mouseEvent)
def mouseMoveEvent(self, mouseEvent):
"""
Executed when the mouse is being moved over the item while being pressed.
"""
if self.handleSelected is not None:
self.interactiveResize(mouseEvent.pos())
else:
super().mouseMoveEvent(mouseEvent)
def mouseReleaseEvent(self, mouseEvent):
"""
Executed when the mouse is released from the item.
"""
super().mouseReleaseEvent(mouseEvent)
self.handleSelected = None
self.mousePressPos = None
self.mousePressRect = None
self.update()
def boundingRect(self):
"""
Returns the bounding rect of the shape (including the resize handles).
"""
o = self.handleSize + self.handleSpace
return self.rect().adjusted(-o, -o, o, o)
def updateHandlesPos(self):
"""
Update current resize handles according to the shape size and position.
"""
s = self.handleSize
b = self.boundingRect()
self.handles[self.handleTopLeft] = QRectF(b.left(), b.top(), s, s)
self.handles[self.handleTopMiddle] = QRectF(b.center().x() - s / 2, b.top(), s, s)
self.handles[self.handleTopRight] = QRectF(b.right() - s, b.top(), s, s)
self.handles[self.handleMiddleLeft] = QRectF(b.left(), b.center().y() - s / 2, s, s)
self.handles[self.handleMiddleRight] = QRectF(b.right() - s, b.center().y() - s / 2, s, s)
self.handles[self.handleBottomLeft] = QRectF(b.left(), b.bottom() - s, s, s)
self.handles[self.handleBottomMiddle] = QRectF(b.center().x() - s / 2, b.bottom() - s, s, s)
self.handles[self.handleBottomRight] = QRectF(b.right() - s, b.bottom() - s, s, s)
def interactiveResize(self, mousePos):
"""
Perform shape interactive resize.
"""
offset = self.handleSize + self.handleSpace
boundingRect = self.boundingRect()
rect = self.rect()
diff = QPointF(0, 0)
self.prepareGeometryChange()
if self.handleSelected == self.handleTopLeft:
fromX = self.mousePressRect.left()
fromY = self.mousePressRect.top()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setLeft(toX)
boundingRect.setTop(toY)
rect.setLeft(boundingRect.left() + offset)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleTopMiddle:
fromY = self.mousePressRect.top()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setY(toY - fromY)
boundingRect.setTop(toY)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleTopRight:
fromX = self.mousePressRect.right()
fromY = self.mousePressRect.top()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setRight(toX)
boundingRect.setTop(toY)
rect.setRight(boundingRect.right() - offset)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleMiddleLeft:
fromX = self.mousePressRect.left()
toX = fromX + mousePos.x() - self.mousePressPos.x()
diff.setX(toX - fromX)
boundingRect.setLeft(toX)
rect.setLeft(boundingRect.left() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleMiddleRight:
print("MR")
fromX = self.mousePressRect.right()
toX = fromX + mousePos.x() - self.mousePressPos.x()
diff.setX(toX - fromX)
boundingRect.setRight(toX)
rect.setRight(boundingRect.right() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomLeft:
fromX = self.mousePressRect.left()
fromY = self.mousePressRect.bottom()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setLeft(toX)
boundingRect.setBottom(toY)
rect.setLeft(boundingRect.left() + offset)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomMiddle:
fromY = self.mousePressRect.bottom()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setY(toY - fromY)
boundingRect.setBottom(toY)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomRight:
fromX = self.mousePressRect.right()
fromY = self.mousePressRect.bottom()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setRight(toX)
boundingRect.setBottom(toY)
rect.setRight(boundingRect.right() - offset)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
self.updateHandlesPos()
def shape(self):
"""
Returns the shape of this item as a QPainterPath in local coordinates.
"""
path = QPainterPath()
path.addRect(self.rect())
if self.isSelected():
for shape in self.handles.values():
path.addEllipse(shape)
return path
def paint(self, painter, option, widget=None):
"""
Paint the node in the graphic view.
"""
painter.setBrush(QBrush(QColor(255, 0, 0, 100)))
painter.setPen(QPen(QColor(0, 0, 0), 1.0, Qt.SolidLine))
painter.drawRect(self.rect())
painter.setRenderHint(QPainter.Antialiasing)
painter.setBrush(QBrush(QColor(255, 0, 0, 255)))
painter.setPen(QPen(QColor(0, 0, 0, 255), 1.0, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
for handle, rect in self.handles.items():
if self.handleSelected is None or handle == self.handleSelected:
painter.drawEllipse(rect)
def main():
app = QApplication(sys.argv)
grview = QGraphicsView()
scene = QGraphicsScene()
scene.setSceneRect(0, 0, 680, 459)
scene.addPixmap(QPixmap('01.png'))
grview.setScene(scene)
item = GraphicsRectItem(0, 0, 300, 150)
scene.addItem(item)
grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
grview.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
我希望场景中有几个物体（矩形），并且每个物体都可以自由移动。
您只添加了一个 GraphicsRectItem，所以您只能看到一个项目，如果您想看到更多，则必须创建更多 GraphicsRectItem 并使用 addItem 将它们添加到场景中：
# ...
import random
def main():
app = QApplication(sys.argv)
grview = QGraphicsView()
scene = QGraphicsScene(grview)
scene.setSceneRect(0, 0, 680, 459)
grview.setScene(scene)
for _ in range(10):
item = GraphicsRectItem(0, 0, 300, 150)
scene.addItem(item)
item.setPos(QPointF(*random.sample(range(300), 2)))
grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
grview.show()
sys.exit(app.exec_())
# ...
更新：
import sys
from PyQt5.QtCore import Qt, QRectF, QPointF, pyqtSlot
from PyQt5.QtGui import QBrush, QPainterPath, QPainter, QColor, QPen, QPixmap
from PyQt5.QtWidgets import (
QGraphicsRectItem,
QApplication,
QGraphicsView,
QGraphicsScene,
QGraphicsItem,
QPushButton,
QWidget,
QVBoxLayout,
)
class GraphicsRectItem(QGraphicsRectItem):
# ...
class Widget(QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
button = QPushButton("Add Rectangle", clicked=self.on_clicked)
self.grview = QGraphicsView()
scene = QGraphicsScene(self.grview)
scene.setSceneRect(0, 0, 680, 459)
self.grview.setScene(scene)
self.grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
lay = QVBoxLayout(self)
lay.addWidget(button)
lay.addWidget(self.grview)
@pyqtSlot()
def on_clicked(self):
item = GraphicsRectItem(0, 0, 300, 150)
item.setPos(QPointF(*random.sample(range(300), 2)))
self.grview.scene().addItem(item)
import random
def main():
app = QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
已创建一组可用于调整形状大小的手柄。 通过跟踪手柄位置的变化，您可以计算形状的新几何形状。
我无法将多个对象添加到场景中。
import sys
from PyQt5.QtCore import Qt, QRectF, QPointF
from PyQt5.QtGui import QBrush, QPainterPath, QPainter, QColor, QPen, QPixmap
from PyQt5.QtWidgets import QGraphicsRectItem, QApplication, QGraphicsView, QGraphicsScene, QGraphicsItem
class GraphicsRectItem(QGraphicsRectItem):
handleTopLeft = 1
handleTopMiddle = 2
handleTopRight = 3
handleMiddleLeft = 4
handleMiddleRight = 5
handleBottomLeft = 6
handleBottomMiddle = 7
handleBottomRight = 8
handleSize = +8.0
handleSpace = -4.0
handleCursors = {
handleTopLeft: Qt.SizeFDiagCursor,
handleTopMiddle: Qt.SizeVerCursor,
handleTopRight: Qt.SizeBDiagCursor,
handleMiddleLeft: Qt.SizeHorCursor,
handleMiddleRight: Qt.SizeHorCursor,
handleBottomLeft: Qt.SizeBDiagCursor,
handleBottomMiddle: Qt.SizeVerCursor,
handleBottomRight: Qt.SizeFDiagCursor,
}
def __init__(self, *args):
"""
Initialize the shape.
"""
super().__init__(*args)
self.handles = {}
self.handleSelected = None
self.mousePressPos = None
self.mousePressRect = None
self.setAcceptHoverEvents(True)
self.setFlag(QGraphicsItem.ItemIsMovable, True)
self.setFlag(QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges, True)
self.setFlag(QGraphicsItem.ItemIsFocusable, True)
self.updateHandlesPos()
def handleAt(self, point):
"""
Returns the resize handle below the given point.
"""
for k, v, in self.handles.items():
if v.contains(point):
return k
return None
def hoverMoveEvent(self, moveEvent):
"""
Executed when the mouse moves over the shape (NOT PRESSED).
"""
if self.isSelected():
handle = self.handleAt(moveEvent.pos())
cursor = Qt.ArrowCursor if handle is None else self.handleCursors[handle]
self.setCursor(cursor)
super().hoverMoveEvent(moveEvent)
def hoverLeaveEvent(self, moveEvent):
"""
Executed when the mouse leaves the shape (NOT PRESSED).
"""
self.setCursor(Qt.ArrowCursor)
super().hoverLeaveEvent(moveEvent)
def mousePressEvent(self, mouseEvent):
"""
Executed when the mouse is pressed on the item.
"""
self.handleSelected = self.handleAt(mouseEvent.pos())
if self.handleSelected:
self.mousePressPos = mouseEvent.pos()
self.mousePressRect = self.boundingRect()
super().mousePressEvent(mouseEvent)
def mouseMoveEvent(self, mouseEvent):
"""
Executed when the mouse is being moved over the item while being pressed.
"""
if self.handleSelected is not None:
self.interactiveResize(mouseEvent.pos())
else:
super().mouseMoveEvent(mouseEvent)
def mouseReleaseEvent(self, mouseEvent):
"""
Executed when the mouse is released from the item.
"""
super().mouseReleaseEvent(mouseEvent)
self.handleSelected = None
self.mousePressPos = None
self.mousePressRect = None
self.update()
def boundingRect(self):
"""
Returns the bounding rect of the shape (including the resize handles).
"""
o = self.handleSize + self.handleSpace
return self.rect().adjusted(-o, -o, o, o)
def updateHandlesPos(self):
"""
Update current resize handles according to the shape size and position.
"""
s = self.handleSize
b = self.boundingRect()
self.handles[self.handleTopLeft] = QRectF(b.left(), b.top(), s, s)
self.handles[self.handleTopMiddle] = QRectF(b.center().x() - s / 2, b.top(), s, s)
self.handles[self.handleTopRight] = QRectF(b.right() - s, b.top(), s, s)
self.handles[self.handleMiddleLeft] = QRectF(b.left(), b.center().y() - s / 2, s, s)
self.handles[self.handleMiddleRight] = QRectF(b.right() - s, b.center().y() - s / 2, s, s)
self.handles[self.handleBottomLeft] = QRectF(b.left(), b.bottom() - s, s, s)
self.handles[self.handleBottomMiddle] = QRectF(b.center().x() - s / 2, b.bottom() - s, s, s)
self.handles[self.handleBottomRight] = QRectF(b.right() - s, b.bottom() - s, s, s)
def interactiveResize(self, mousePos):
"""
Perform shape interactive resize.
"""
offset = self.handleSize + self.handleSpace
boundingRect = self.boundingRect()
rect = self.rect()
diff = QPointF(0, 0)
self.prepareGeometryChange()
if self.handleSelected == self.handleTopLeft:
fromX = self.mousePressRect.left()
fromY = self.mousePressRect.top()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setLeft(toX)
boundingRect.setTop(toY)
rect.setLeft(boundingRect.left() + offset)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleTopMiddle:
fromY = self.mousePressRect.top()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setY(toY - fromY)
boundingRect.setTop(toY)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleTopRight:
fromX = self.mousePressRect.right()
fromY = self.mousePressRect.top()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setRight(toX)
boundingRect.setTop(toY)
rect.setRight(boundingRect.right() - offset)
rect.setTop(boundingRect.top() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleMiddleLeft:
fromX = self.mousePressRect.left()
toX = fromX + mousePos.x() - self.mousePressPos.x()
diff.setX(toX - fromX)
boundingRect.setLeft(toX)
rect.setLeft(boundingRect.left() + offset)
self.setRect(rect)
elif self.handleSelected == self.handleMiddleRight:
print("MR")
fromX = self.mousePressRect.right()
toX = fromX + mousePos.x() - self.mousePressPos.x()
diff.setX(toX - fromX)
boundingRect.setRight(toX)
rect.setRight(boundingRect.right() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomLeft:
fromX = self.mousePressRect.left()
fromY = self.mousePressRect.bottom()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setLeft(toX)
boundingRect.setBottom(toY)
rect.setLeft(boundingRect.left() + offset)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomMiddle:
fromY = self.mousePressRect.bottom()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setY(toY - fromY)
boundingRect.setBottom(toY)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
elif self.handleSelected == self.handleBottomRight:
fromX = self.mousePressRect.right()
fromY = self.mousePressRect.bottom()
toX = fromX + mousePos.x() - self.mousePressPos.x()
toY = fromY + mousePos.y() - self.mousePressPos.y()
diff.setX(toX - fromX)
diff.setY(toY - fromY)
boundingRect.setRight(toX)
boundingRect.setBottom(toY)
rect.setRight(boundingRect.right() - offset)
rect.setBottom(boundingRect.bottom() - offset)
self.setRect(rect)
self.updateHandlesPos()
def shape(self):
"""
Returns the shape of this item as a QPainterPath in local coordinates.
"""
path = QPainterPath()
path.addRect(self.rect())
if self.isSelected():
for shape in self.handles.values():
path.addEllipse(shape)
return path
def paint(self, painter, option, widget=None):
"""
Paint the node in the graphic view.
"""
painter.setBrush(QBrush(QColor(255, 0, 0, 100)))
painter.setPen(QPen(QColor(0, 0, 0), 1.0, Qt.SolidLine))
painter.drawRect(self.rect())
painter.setRenderHint(QPainter.Antialiasing)
painter.setBrush(QBrush(QColor(255, 0, 0, 255)))
painter.setPen(QPen(QColor(0, 0, 0, 255), 1.0, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
for handle, rect in self.handles.items():
if self.handleSelected is None or handle == self.handleSelected:
painter.drawEllipse(rect)
def main():
app = QApplication(sys.argv)
grview = QGraphicsView()
scene = QGraphicsScene()
scene.setSceneRect(0, 0, 680, 459)
scene.addPixmap(QPixmap('01.png'))
grview.setScene(scene)
item = GraphicsRectItem(0, 0, 300, 150)
scene.addItem(item)
grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
grview.show()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
我希望场景中有几个物体（矩形），并且每个物体都可以自由移动。
您只添加了一个 GraphicsRectItem，所以您只能看到一个项目，如果您想看到更多，则必须创建更多 GraphicsRectItem 并使用 addItem 将它们添加到场景中：
# ...
import random
def main():
app = QApplication(sys.argv)
grview = QGraphicsView()
scene = QGraphicsScene(grview)
scene.setSceneRect(0, 0, 680, 459)
grview.setScene(scene)
for _ in range(10):
item = GraphicsRectItem(0, 0, 300, 150)
scene.addItem(item)
item.setPos(QPointF(*random.sample(range(300), 2)))
grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
grview.show()
sys.exit(app.exec_())
# ...
更新：
import sys
from PyQt5.QtCore import Qt, QRectF, QPointF, pyqtSlot
from PyQt5.QtGui import QBrush, QPainterPath, QPainter, QColor, QPen, QPixmap
from PyQt5.QtWidgets import (
QGraphicsRectItem,
QApplication,
QGraphicsView,
QGraphicsScene,
QGraphicsItem,
QPushButton,
QWidget,
QVBoxLayout,
)
class GraphicsRectItem(QGraphicsRectItem):
# ...
class Widget(QWidget):
def __init__(self, parent=None):
super(Widget, self).__init__(parent)
button = QPushButton("Add Rectangle", clicked=self.on_clicked)
self.grview = QGraphicsView()
scene = QGraphicsScene(self.grview)
scene.setSceneRect(0, 0, 680, 459)
self.grview.setScene(scene)
self.grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
lay = QVBoxLayout(self)
lay.addWidget(button)
lay.addWidget(self.grview)
@pyqtSlot()
def on_clicked(self):
item = GraphicsRectItem(0, 0, 300, 150)
item.setPos(QPointF(*random.sample(range(300), 2)))
self.grview.scene().addItem(item)
import random
def main():
app = QApplication(sys.argv)
w = Widget()
w.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()