将rectangle放入QGraphicsScene并用鼠标移动后，我怎么能用鼠标调整它？
如果没有人知道答案，那么一个例子也可能很好，我正在使用PyQt4在Python中开发。
我知道这里有类似的问题，但他们不会分别回答我。
我的简化代码：
import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
app = QApplication(sys.argv)
grview = QGraphicsView()
scene = QGraphicsScene()
scene.setSceneRect(0, 0, 512, 512)
scene.addPixmap(QPixmap('01.png'))
grview.setScene(scene)
item = QGraphicsRectItem(0, 0, 300, 150)
pen = QPen(Qt.darkMagenta)
pen.setWidth(4)
item.setPen(pen)
item.setFlag(QGraphicsItem.ItemIsMovable)
scene.addItem(item)
grview.fitInView(scene.sceneRect(), Qt.KeepAspectRatio)
grview.show()
sys.exit(app.exec_())
答案 0 :(得分：10)
您需要自己实施调整大小。为此，您需要继承QGraphicsRectItem并实现鼠标事件处理程序：mousePressEvent，mouseMoveEvent，mouseReleaseEvent。
一般的想法如下：
我之前写了一些代码，它与PyQt5完美配合，但它也适用于PyQt4。您应该能够根据自己的需要进行调整：
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()
答案 1 :(得分：2)
这是resizing a QGraphicsItem的一个例子，它是用C ++编写的。如果你或这里的某人重新写入python，它可能会有用。
答案 2 :(得分：2)
我也尝试做类似的任务，除了在我的情况下我需要一个可重用的对象，可以继承需要调整大小的父项。以下是使用此Resizer类将调整大小锚点添加到其父QGraphicsRectItem的示例。
Resizer类继承QGraphicsObject并重新实现paint方法。 itemChange Resizer方法会发出一个信号，该信号已分配给父resize类中的Box方法。这又使用来自缩放器的位置变化信息来调整盒子的矩形。
这样，调整器也可以重用于其他项目，而无需重新实现鼠标按下/移动/释放事件。
import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class Box(QGraphicsRectItem):
def __init__(self, position, rect=QRectF(0, 0, 100, 50), parent=None, scene=None):
super().__init__(rect, parent, scene)
self.setFlag(QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QGraphicsItem.ItemIsMovable, True)
self.setFlag(QGraphicsItem.ItemIsFocusable, True)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges, True)
self.setPos(position)
self.resizer = Resizer(parent=self)
resizerWidth = self.resizer.rect.width() / 2
resizerOffset = QPointF(resizerWidth, resizerWidth)
self.resizer.setPos(self.rect().bottomRight() - resizerOffset)
self.resizer.resizeSignal.connect(self.resize)
def paint(self, painter, option, widget=None):
pen = QPen()
pen.setColor(Qt.black)
painter.setPen(pen)
painter.setBrush(Qt.transparent)
painter.drawRect(self.rect())
@pyqtSlot()
def resize(self, change):
self.setRect(self.rect().adjusted(0, 0, change.x(), change.y()))
self.prepareGeometryChange()
self.update()
class Resizer(QGraphicsObject):
resizeSignal = pyqtSignal(QPointF)
def __init__(self, rect=QRectF(0, 0, 10, 10), parent=None):
super().__init__(parent)
self.setFlag(QGraphicsItem.ItemIsMovable, True)
self.setFlag(QGraphicsItem.ItemIsSelectable, True)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges, True)
self.rect = rect
def boundingRect(self):
return self.rect
def paint(self, painter, option, widget=None):
if self.isSelected():
pen = QPen()
pen.setStyle(Qt.DotLine)
painter.setPen(pen)
painter.drawEllipse(self.rect)
def itemChange(self, change, value):
if change == QGraphicsItem.ItemPositionChange:
if self.isSelected():
self.resizeSignal.emit(value - self.pos())
return value
if __name__ == "__main__":
app = QApplication(sys.argv)
view = QGraphicsView()
scene = QGraphicsScene()
scene.setSceneRect(0, 0, 500, 1000)
view.setScene(scene)
box = Box(QPointF(50, 50), scene=scene)
view.show()
sys.exit(app.exec_())
答案 3 :(得分：0)
我还尝试使用QGraphicsPixmapItem类，从@pbreach修改resizer类，这对我有用：
class Resizer(QGraphicsObject):
resizeSignal = pyqtSignal(QGraphicsItem.GraphicsItemChange,QPointF)
def __init__(self,rect = QRectF(0,0,10,10),parent=None):
super().__init__(parent)
self.setFlag(QGraphicsItem.ItemIsMovable,True)
self.setFlag(QGraphicsItem.ItemIsSelectable,True)
self.setFlag(QGraphicsItem.ItemSendsGeometryChanges,True)
self.setCursor(Qt.SizeFDiagCursor)
self.rect = rect
self.hide()
def boundingRect(self):
return self.rect
def paint(self,painter,option,widget=None):
if self.isSelected():
pen = QPen()
pen.setStyle(Qt.DotLine)
painter.setPen(pen)
painter.setRenderHint(QPainter.Antialiasing)
painter.drawEllipse(self.rect)
self.update()
def itemChange(self,change,value):
self.prepareGeometryChange()
if change == QGraphicsItem.ItemPositionChange:
if self.isSelected():
self.resizeSignal.emit(change,self.pos())
return super(Resizer,self).itemChange(change,value)
'''END CLASS'''
class GraphicLayer(QGraphicsPixmapItem):
def __init__(self,top_left_x,top_left_y,graphic,rect=QRectF(0,0,100,100),parent=None,scene=None):
super().__init__(parent=parent)
self.rect = rect
self.setPixmap(graphic)
self.graphic = graphic
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.setPos(top_left_x,top_left_y)
# Resizer actions
self.resizer = Resizer(parent=self)
r_width = self.resizer.boundingRect().width() - 2
self.r_offset = QPointF(r_width,r_width)
self.resizer.setPos(self.boundingRect().bottomRight()-self.r_offset)
self.resizer.resizeSignal.connect(self.resize)
def set_tag(self,item_id):
self.tag = item_id
def get_tag(self):
return self.tag
def hoverMoveEvent(self,event):
if self.isSelected():
self.resizer.show()
else:
self.resizer.hide()
def hoverLeave(self,event):
self.resizer.hide()
@pyqtSlot()
def resize(self,change,value):
pixmap = self.graphic.scaled(value.x(),value.y(),transformMode=Qt.SmoothTransformation)
self.setPixmap(pixmap)
self.prepareGeometryChange()
self.update()
"""END OF CLASS"""
这里是此类的一个小gif。重要！这是在PyQt5中完成的 Not enough reputation to post images
请让我知道您的想法！
答案 4 :(得分：0)
这是我的，代码更少：
class BoxItem(QGraphicsObject):
def __init__(self):
super().__init__()
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.rect = QRect(0, 0, 100, 100)
self.moving = False
self.origin = QPoint()
# # Resizer actions
# self.resizer.setPos(self.boundingRect().bottomRight() - self.r_offset)
# self.resizer.resizeSignal.connect(self.resize)
def corner_rect(self) -> QRect:
""" Return corner rect geometry """
return QRect(self.rect.right() - 10, self.rect.bottom() - 10, 10, 10)
def boundingRect(self) -> QRectF:
""" Override boundingRect """
return self.rect.adjusted(-10, -10, 10, 10)
def paint(self, painter, option, widget=None):
""" OVerride paint """
brush = QBrush(QColor(255, 100, 100, 200))
brush.setStyle(Qt.Dense7Pattern)
painter.setBrush(brush)
painter.drawRect(self.rect)
if self.isSelected():
painter.setBrush(QBrush(QColor(Qt.red)))
painter.setPen(Qt.NoPen)
painter.drawRect(self.corner_rect())
# Draw selection
pen = QPen(QColor(Qt.green))
pen.setStyle(Qt.DotLine)
painter.setPen(pen)
painter.setBrush(Qt.NoBrush)
painter.drawRect(self.rect)
self.update()
def hoverMoveEvent(self, event: QMouseEvent):
""" Override hover move Event : Display cursor """
if self.isSelected() & self.corner_rect().contains(event.pos().toPoint()):
self.setCursor(Qt.SizeFDiagCursor)
else:
self.setCursor(Qt.ArrowCursor)
super().hoverMoveEvent(event)
def mousePressEvent(self, event: QMouseEvent):
""" override mouse Press Event """
if self.isSelected() & self.corner_rect().contains(
QPoint(event.pos().toPoint())
):
self.moving = True
self.origin = self.rect.topLeft()
else:
super().mousePressEvent(event)
def mouseReleaseEvent(self, event: QMouseEvent):
""" Override mouse release event """
self.moving = False
super().mouseReleaseEvent(event)
def mouseMoveEvent(self, event: QMouseEvent):
""" Override mouse move event """
if self.moving:
# If moving is set from mousePressEvent , change geometry
self.prepareGeometryChange()
pos = event.pos().toPoint()
if pos.x() >= self.origin.x():
self.rect.setRight(pos.x())
else:
self.rect.setLeft(pos.x())
if pos.y() >= self.origin.y():
self.rect.setBottom(pos.y())
else:
self.rect.setTop(pos.y())
self.rect = self.rect.normalized()
self.update()
return
else:
super().mouseMoveEvent(event)
答案 5 :(得分：0)
Daniele's code 非常有帮助，我特别喜欢调整大小的手柄。我不喜欢这样的事实，即您可以将矩形移动到窗口限制之外或调整它的大小，直到它的宽度或高度为负。
此代码强制限制移动和调整大小，因此您不会导致这些问题。为了让这个例子保持简单，我省略了调整大小的句柄。
import typing
from PySide6.QtCore import QRectF, QSize
from PySide6.QtGui import QPen, QBrush, QColor, QResizeEvent
from PySide6.QtWidgets import (QApplication, QGraphicsView, QGraphicsScene,
QGraphicsItem, QGraphicsRectItem, QMainWindow,
QVBoxLayout, QWidget)
class ResizableRect(QGraphicsRectItem):
def __init__(self, *args):
super().__init__(*args)
self.setFlag(QGraphicsItem.ItemIsMovable, True)
self.setPen(QPen(QBrush(QColor('blue')), 5))
self.selected_edge = None
self.click_pos = self.click_rect = None
def mousePressEvent(self, event):
""" The mouse is pressed, start tracking movement. """
self.click_pos = event.pos()
rect = self.rect()
if abs(rect.left() - self.click_pos.x()) < 5:
self.selected_edge = 'left'
elif abs(rect.right() - self.click_pos.x()) < 5:
self.selected_edge = 'right'
elif abs(rect.top() - self.click_pos.y()) < 5:
self.selected_edge = 'top'
elif abs(rect.bottom() - self.click_pos.y()) < 5:
self.selected_edge = 'bottom'
else:
self.selected_edge = None
self.click_pos = event.pos()
self.click_rect = rect
super().mousePressEvent(event)
def mouseMoveEvent(self, event):
""" Continue tracking movement while the mouse is pressed. """
# Calculate how much the mouse has moved since the click.
pos = event.pos()
x_diff = pos.x() - self.click_pos.x()
y_diff = pos.y() - self.click_pos.y()
# Start with the rectangle as it was when clicked.
rect = QRectF(self.click_rect)
# Then adjust by the distance the mouse moved.
if self.selected_edge is None:
rect.translate(x_diff, y_diff)
elif self.selected_edge == 'top':
rect.adjust(0, y_diff, 0, 0)
elif self.selected_edge == 'left':
rect.adjust(x_diff, 0, 0, 0)
elif self.selected_edge == 'bottom':
rect.adjust(0, 0, 0, y_diff)
elif self.selected_edge == 'right':
rect.adjust(0, 0, x_diff, 0)
# Figure out the limits of movement. I did it by updating the scene's
# rect after the window resizes.
scene_rect = self.scene().sceneRect()
view_left = scene_rect.left()
view_top = scene_rect.top()
view_right = scene_rect.right()
view_bottom = scene_rect.bottom()
# Next, check if the rectangle has been dragged out of bounds.
if rect.top() < view_top:
if self.selected_edge is None:
rect.translate(0, view_top-rect.top())
else:
rect.setTop(view_top)
if rect.left() < view_left:
if self.selected_edge is None:
rect.translate(view_left-rect.left(), 0)
else:
rect.setLeft(view_left)
if view_bottom < rect.bottom():
if self.selected_edge is None:
rect.translate(0, view_bottom - rect.bottom())
else:
rect.setBottom(view_bottom)
if view_right < rect.right():
if self.selected_edge is None:
rect.translate(view_right - rect.right(), 0)
else:
rect.setRight(view_right)
# Also check if the rectangle has been dragged inside out.
if rect.width() < 5:
if self.selected_edge == 'left':
rect.setLeft(rect.right() - 5)
else:
rect.setRight(rect.left() + 5)
if rect.height() < 5:
if self.selected_edge == 'top':
rect.setTop(rect.bottom() - 5)
else:
rect.setBottom(rect.top() + 5)
# Finally, update the rect that is now guaranteed to stay in bounds.
self.setRect(rect)
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
central = QWidget(self)
self.setCentralWidget(central)
self.rect = ResizableRect()
scene = QGraphicsScene(0, 0, 300, 300)
scene.addItem(self.rect)
self.view = QGraphicsView(central)
self.view.setScene(scene)
layout = QVBoxLayout(central)
self.setLayout(layout)
layout.addWidget(self.view)
self.old_size: typing.Optional[QSize] = None
def show(self):
super().show()
self.resize_scene()
def resizeEvent(self, event: QResizeEvent):
super().resizeEvent(event)
self.resize_scene()
def resize_scene(self):
if not self.isVisible():
# Viewport size isn't set yet, so calculation won't work.
return
size = self.view.maximumViewportSize()
if self.old_size is None:
new_rect = QRectF(size.width()/4, size.height()/4,
size.width()/2, size.height()/2)
else:
old_rect = QRectF(self.rect.rect())
x_scale = size.width() / self.old_size.width()
y_scale = size.height() / self.old_size.height()
new_rect = QRectF(old_rect.left()*x_scale, old_rect.top()*y_scale,
old_rect.width()*x_scale, old_rect.height()*y_scale)
self.rect.setRect(new_rect)
self.view.scene().setSceneRect(0, 0, size.width(), size.height())
self.old_size = size
def main():
app = QApplication()
window = MainWindow()
window.show()
app.exec_()
main()