似乎无法使用 QPainter（或任何其他方法）旋转自定义 QGraphicsItem。
Seems impossible to rotate custom QGraphicsItem using QPainter (or any other method.)
这是代码。它运行。展示这个错误。右键单击椭圆，通过在椭圆上单击并拖动来缩放它。右键单击它 > "Done editing"。然后用 "Rotate."
做同样的事情
我已经尝试了 10 多种不同的排列方式，使用 self.setRotation、self.setTransform、painter.rotate 等等...它唯一一次旋转是在我使用 self.setTransform(self.transform().rotate(r)) 但结果是错误的：以错误的顺序缩放和旋转什么的。
from PyQt5.QtWidgets import QGraphicsItem, QMenu
from PyQt5.QtGui import QTransform, QPen, QPainter, QColor, QBrush
from PyQt5.QtCore import Qt, QPointF, QRectF, QEvent
from math import sqrt
def scaleRect(rect, scale_x, scale_y):
T = QTransform.fromScale(scale_x, scale_y)
return T.mapRect(rect)
def debugPrintTransformMatrix(T):
print(str(T.m11()) + ' ' + str(T.m12()) + ' ' + str(T.m13()))
print(str(T.m21()) + ' ' + str(T.m22()) + ' ' + str(T.m23()))
print(str(T.m31()) + ' ' + str(T.m32()) + ' ' + str(T.m33()))
# Assumes no shearing or stretching.
# Only Rotation, Translation, and Scaling.
def extractTransformScale(T):
# This is math matrix notation transposed (debug print self.sceneTransform() to see)
Sx = sqrt(T.m11()**2 + T.m12()**2)
Sy = sqrt(T.m21()**2 + T.m22()**2)
return Sx, Sy
def extractTransformTranslate(T):
return T.m31(), T.m32()
class Object(QGraphicsItem):
def sceneEvent(self, event):
if event.type() == QEvent.GraphicsSceneMouseMove:
# move, scale, or rotate
if self._mode in ['scale', 'rotate']:
mouse_pos = event.scenePos()
last_pos = event.lastScenePos()
if self._mode == 'scale':
s = self.mouseScalingFactors(mouse_pos, last_pos)
self.setTransform(self.transform().scale(*s))
if self._mode == 'rotate':
r = self.mouseRotationAngle(mouse_pos, last_pos)
self.setRotation(self.rotation() + r)
return True
return super().sceneEvent(event)
def __init__(self):
super().__init__()
self.setFlags(QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsFocusable | QGraphicsItem.ItemIsSelectable)
self._selectionPen = QPen(Qt.black, 1.0, style=Qt.DotLine, cap=Qt.FlatCap)
self._lastPos = QPointF(0, 0)
self.setPos(self._lastPos)
self._mode = 'neutral'
def setRenderHints(self, painter):
painter.setRenderHints(QPainter.SmoothPixmapTransform | QPainter.HighQualityAntialiasing | QPainter.TextAntialiasing)
def boundingRectExtraScale(self):
return (1.2 , 1.2)
def mouseScalingFactors(self, pos, last_pos):
delta = pos - last_pos
return (1.01 ** delta.x(), 1.01 ** delta.y())
def mouseRotationAngle(self, pos, last_pos):
return 1 #TODO
def createDefaultContextMenu(self):
menu = QMenu()
if self._mode == 'neutral':
menu.addAction('Scale').triggered.connect(lambda: self.setMode('scale'))
menu.addAction('Rotate').triggered.connect(lambda: self.setMode('rotate'))
else:
menu.addAction('Done Editing').triggered.connect(lambda: self.setMode('neutral'))
return menu
def contextMenuEvent(self, event):
menu = self.createDefaultContextMenu()
menu.exec(event.screenPos())
def setMode(self, mode):
self._mode = mode
def setSelected(self, selected):
super().setSelected(selected)
self.update()
class ShapedObject(Object):
def __init__(self):
super().__init__()
self._shape = {
'name' : 'ellipse',
'radius': 35
}
self._brush = QBrush(Qt.darkGreen)
self._pen = QPen(Qt.yellow, 3)
def shapeDef(self):
return self._shape
def boundingRect(self):
rect = self.shapeRect()
s = self.boundingRectExtraScale()
return scaleRect(rect, *s)
def shape(self): #TODO QPainterPath shape for collision detection
# Should call self.boundingRectExtraScale()
return super().shape()
def paint(self, painter, option, widget):
self.setRenderHints(painter)
#super().paint(painter, option, widget)
shape = self.shapeDef()
name = shape['name']
painter.setBrush(self._brush)
painter.setPen(self._pen)
painter.save()
# ********** HERE IS THE PROBLEM *************
debugPrintTransformMatrix(painter.transform())
painter.rotate(5)
debugPrintTransformMatrix(painter.transform())
rect = self.shapeRect()
if name == 'ellipse':
painter.drawEllipse(rect)
painter.restore()
def shapeRect(self):
shape = self.shapeDef()
name = shape['name']
if name == 'ellipse':
r = shape['radius']
rect = QRectF(-r, -r, 2*r, 2*r)
return rect
####
import sys
from PyQt5.QtWidgets import QMainWindow, QGraphicsScene, QGraphicsView, QApplication
if __name__ == '__main__':
app = QApplication(sys.argv)
window = QMainWindow()
view = QGraphicsView()
scene = QGraphicsScene()
view.setScene(scene)
window.setCentralWidget(view)
ellipse = ShapedObject()
scene.addItem(ellipse)
window.show()
sys.exit(app.exec_())
开始使用了。这是旋转/缩放操作的顺序。永远不要用圆来测试你的旋转代码，哈哈！
from PyQt5.QtWidgets import QGraphicsItem, QMenu, QGraphicsRotation, QGraphicsScale
from PyQt5.QtGui import QTransform, QPen, QPainter, QColor, QBrush, QPainterPath
from PyQt5.QtCore import Qt, QPointF, QRectF, QEvent
from math import sqrt
def scaleRect(rect, scale_x, scale_y):
T = QTransform.fromScale(scale_x, scale_y)
return T.mapRect(rect)
def debugPrintTransformMatrix(T):
print(str(T.m11()) + ' ' + str(T.m12()) + ' ' + str(T.m13()))
print(str(T.m21()) + ' ' + str(T.m22()) + ' ' + str(T.m23()))
print(str(T.m31()) + ' ' + str(T.m32()) + ' ' + str(T.m33()))
# Assumes no shearing or stretching.
# Only Rotation, Translation, and Scaling.
def extractTransformScale(T):
# This is math matrix notation transposed (debug print self.sceneTransform() to see)
Sx = sqrt(T.m11()**2 + T.m12()**2)
Sy = sqrt(T.m21()**2 + T.m22()**2)
return Sx, Sy
def extractTransformTranslate(T):
return T.m31(), T.m32()
class Object(QGraphicsItem):
def sceneEvent(self, event):
if event.type() == QEvent.GraphicsSceneMouseMove:
# move, scale, or rotate
if self._mode in ['scale', 'rotate']:
mouse_pos = event.scenePos()
last_pos = event.lastScenePos()
if self._mode == 'scale':
s = self.mouseScalingFactors(mouse_pos, last_pos)
self.applyScaleTransform(*s)
if self._mode == 'rotate':
r = self.mouseRotationAngle(mouse_pos, last_pos)
self.applyRotateTransform(r)
return True
return super().sceneEvent(event)
def __init__(self):
super().__init__()
self.setFlags(QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsFocusable | QGraphicsItem.ItemIsSelectable)
self._selectionPen = QPen(Qt.black, 1.0, style=Qt.DotLine, cap=Qt.FlatCap)
self._lastPos = QPointF(0, 0)
self.setPos(self._lastPos)
self._mode = 'neutral'
self._scale = QGraphicsScale()
self._rotate = QGraphicsRotation()
self.setTransformations([self._rotate, self._scale])
def applyRotateTransform(self, angle):
self._rotate.setAngle(self._rotate.angle() + 15)
def applyScaleTransform(self, sx, sy):
self._scale.setXScale(sx * self._scale.xScale())
self._scale.setYScale(sy * self._scale.yScale())
def setRenderHints(self, painter):
painter.setRenderHints(QPainter.SmoothPixmapTransform | QPainter.HighQualityAntialiasing | QPainter.TextAntialiasing)
def boundingRectExtraScale(self):
return (1.2 , 1.2)
def mouseScalingFactors(self, pos, last_pos):
delta = pos - last_pos
return (1.01 ** delta.x(), 1.01 ** delta.y())
def mouseRotationAngle(self, pos, last_pos):
return 1 #TODO
def createDefaultContextMenu(self):
menu = QMenu()
if self._mode == 'neutral':
menu.addAction('Scale').triggered.connect(lambda: self.setMode('scale'))
menu.addAction('Rotate').triggered.connect(lambda: self.setMode('rotate'))
else:
menu.addAction('Done Editing').triggered.connect(lambda: self.setMode('neutral'))
return menu
def contextMenuEvent(self, event):
menu = self.createDefaultContextMenu()
menu.exec(event.screenPos())
def setMode(self, mode):
self._mode = mode
def setSelected(self, selected):
super().setSelected(selected)
self.update()
class ShapedObject(Object):
def __init__(self):
super().__init__()
self._shape = {
'name' : 'ellipse',
'radius': 35
}
self._brush = QBrush(Qt.darkGreen)
self._pen = QPen(Qt.yellow, 3)
def shapeDef(self):
return self._shape
def boundingRect(self):
rect = self.shapeRect()
s = self.boundingRectExtraScale()
return scaleRect(rect, *s)
def shape(self): #TODO QPainterPath shape for collision detection
# Should call self.boundingRectExtraScale()
return super().shape()
def paint(self, painter, option, widget):
self.setRenderHints(painter)
#super().paint(painter, option, widget)
shape = self.shapeDef()
name = shape['name']
painter.setBrush(self._brush)
painter.setPen(self._pen)
painter.save()
path = QPainterPath()
if name == 'ellipse':
r = shape['radius']
path.addEllipse(QPointF(0, 0), r, r)
painter.drawPath(path)
painter.restore()
def shapeRect(self):
shape = self.shapeDef()
name = shape['name']
if name == 'ellipse':
r = shape['radius']
rect = QRectF(-r, -r, 2*r, 2*r)
return rect
####
import sys
from PyQt5.QtWidgets import QMainWindow, QGraphicsScene, QGraphicsView, QApplication
if __name__ == '__main__':
app = QApplication(sys.argv)
window = QMainWindow()
view = QGraphicsView()
scene = QGraphicsScene()
view.setScene(scene)
window.setCentralWidget(view)
ellipse = ShapedObject()
scene.addItem(ellipse)
window.show()
sys.exit(app.exec_())
这是代码。它运行。展示这个错误。右键单击椭圆，通过在椭圆上单击并拖动来缩放它。右键单击它 > "Done editing"。然后用 "Rotate."
做同样的事情我已经尝试了 10 多种不同的排列方式，使用 self.setRotation、self.setTransform、painter.rotate 等等...它唯一一次旋转是在我使用 self.setTransform(self.transform().rotate(r)) 但结果是错误的：以错误的顺序缩放和旋转什么的。
from PyQt5.QtWidgets import QGraphicsItem, QMenu
from PyQt5.QtGui import QTransform, QPen, QPainter, QColor, QBrush
from PyQt5.QtCore import Qt, QPointF, QRectF, QEvent
from math import sqrt
def scaleRect(rect, scale_x, scale_y):
T = QTransform.fromScale(scale_x, scale_y)
return T.mapRect(rect)
def debugPrintTransformMatrix(T):
print(str(T.m11()) + ' ' + str(T.m12()) + ' ' + str(T.m13()))
print(str(T.m21()) + ' ' + str(T.m22()) + ' ' + str(T.m23()))
print(str(T.m31()) + ' ' + str(T.m32()) + ' ' + str(T.m33()))
# Assumes no shearing or stretching.
# Only Rotation, Translation, and Scaling.
def extractTransformScale(T):
# This is math matrix notation transposed (debug print self.sceneTransform() to see)
Sx = sqrt(T.m11()**2 + T.m12()**2)
Sy = sqrt(T.m21()**2 + T.m22()**2)
return Sx, Sy
def extractTransformTranslate(T):
return T.m31(), T.m32()
class Object(QGraphicsItem):
def sceneEvent(self, event):
if event.type() == QEvent.GraphicsSceneMouseMove:
# move, scale, or rotate
if self._mode in ['scale', 'rotate']:
mouse_pos = event.scenePos()
last_pos = event.lastScenePos()
if self._mode == 'scale':
s = self.mouseScalingFactors(mouse_pos, last_pos)
self.setTransform(self.transform().scale(*s))
if self._mode == 'rotate':
r = self.mouseRotationAngle(mouse_pos, last_pos)
self.setRotation(self.rotation() + r)
return True
return super().sceneEvent(event)
def __init__(self):
super().__init__()
self.setFlags(QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsFocusable | QGraphicsItem.ItemIsSelectable)
self._selectionPen = QPen(Qt.black, 1.0, style=Qt.DotLine, cap=Qt.FlatCap)
self._lastPos = QPointF(0, 0)
self.setPos(self._lastPos)
self._mode = 'neutral'
def setRenderHints(self, painter):
painter.setRenderHints(QPainter.SmoothPixmapTransform | QPainter.HighQualityAntialiasing | QPainter.TextAntialiasing)
def boundingRectExtraScale(self):
return (1.2 , 1.2)
def mouseScalingFactors(self, pos, last_pos):
delta = pos - last_pos
return (1.01 ** delta.x(), 1.01 ** delta.y())
def mouseRotationAngle(self, pos, last_pos):
return 1 #TODO
def createDefaultContextMenu(self):
menu = QMenu()
if self._mode == 'neutral':
menu.addAction('Scale').triggered.connect(lambda: self.setMode('scale'))
menu.addAction('Rotate').triggered.connect(lambda: self.setMode('rotate'))
else:
menu.addAction('Done Editing').triggered.connect(lambda: self.setMode('neutral'))
return menu
def contextMenuEvent(self, event):
menu = self.createDefaultContextMenu()
menu.exec(event.screenPos())
def setMode(self, mode):
self._mode = mode
def setSelected(self, selected):
super().setSelected(selected)
self.update()
class ShapedObject(Object):
def __init__(self):
super().__init__()
self._shape = {
'name' : 'ellipse',
'radius': 35
}
self._brush = QBrush(Qt.darkGreen)
self._pen = QPen(Qt.yellow, 3)
def shapeDef(self):
return self._shape
def boundingRect(self):
rect = self.shapeRect()
s = self.boundingRectExtraScale()
return scaleRect(rect, *s)
def shape(self): #TODO QPainterPath shape for collision detection
# Should call self.boundingRectExtraScale()
return super().shape()
def paint(self, painter, option, widget):
self.setRenderHints(painter)
#super().paint(painter, option, widget)
shape = self.shapeDef()
name = shape['name']
painter.setBrush(self._brush)
painter.setPen(self._pen)
painter.save()
# ********** HERE IS THE PROBLEM *************
debugPrintTransformMatrix(painter.transform())
painter.rotate(5)
debugPrintTransformMatrix(painter.transform())
rect = self.shapeRect()
if name == 'ellipse':
painter.drawEllipse(rect)
painter.restore()
def shapeRect(self):
shape = self.shapeDef()
name = shape['name']
if name == 'ellipse':
r = shape['radius']
rect = QRectF(-r, -r, 2*r, 2*r)
return rect
####
import sys
from PyQt5.QtWidgets import QMainWindow, QGraphicsScene, QGraphicsView, QApplication
if __name__ == '__main__':
app = QApplication(sys.argv)
window = QMainWindow()
view = QGraphicsView()
scene = QGraphicsScene()
view.setScene(scene)
window.setCentralWidget(view)
ellipse = ShapedObject()
scene.addItem(ellipse)
window.show()
sys.exit(app.exec_())
开始使用了。这是旋转/缩放操作的顺序。永远不要用圆来测试你的旋转代码，哈哈！
from PyQt5.QtWidgets import QGraphicsItem, QMenu, QGraphicsRotation, QGraphicsScale
from PyQt5.QtGui import QTransform, QPen, QPainter, QColor, QBrush, QPainterPath
from PyQt5.QtCore import Qt, QPointF, QRectF, QEvent
from math import sqrt
def scaleRect(rect, scale_x, scale_y):
T = QTransform.fromScale(scale_x, scale_y)
return T.mapRect(rect)
def debugPrintTransformMatrix(T):
print(str(T.m11()) + ' ' + str(T.m12()) + ' ' + str(T.m13()))
print(str(T.m21()) + ' ' + str(T.m22()) + ' ' + str(T.m23()))
print(str(T.m31()) + ' ' + str(T.m32()) + ' ' + str(T.m33()))
# Assumes no shearing or stretching.
# Only Rotation, Translation, and Scaling.
def extractTransformScale(T):
# This is math matrix notation transposed (debug print self.sceneTransform() to see)
Sx = sqrt(T.m11()**2 + T.m12()**2)
Sy = sqrt(T.m21()**2 + T.m22()**2)
return Sx, Sy
def extractTransformTranslate(T):
return T.m31(), T.m32()
class Object(QGraphicsItem):
def sceneEvent(self, event):
if event.type() == QEvent.GraphicsSceneMouseMove:
# move, scale, or rotate
if self._mode in ['scale', 'rotate']:
mouse_pos = event.scenePos()
last_pos = event.lastScenePos()
if self._mode == 'scale':
s = self.mouseScalingFactors(mouse_pos, last_pos)
self.applyScaleTransform(*s)
if self._mode == 'rotate':
r = self.mouseRotationAngle(mouse_pos, last_pos)
self.applyRotateTransform(r)
return True
return super().sceneEvent(event)
def __init__(self):
super().__init__()
self.setFlags(QGraphicsItem.ItemIsMovable | QGraphicsItem.ItemIsFocusable | QGraphicsItem.ItemIsSelectable)
self._selectionPen = QPen(Qt.black, 1.0, style=Qt.DotLine, cap=Qt.FlatCap)
self._lastPos = QPointF(0, 0)
self.setPos(self._lastPos)
self._mode = 'neutral'
self._scale = QGraphicsScale()
self._rotate = QGraphicsRotation()
self.setTransformations([self._rotate, self._scale])
def applyRotateTransform(self, angle):
self._rotate.setAngle(self._rotate.angle() + 15)
def applyScaleTransform(self, sx, sy):
self._scale.setXScale(sx * self._scale.xScale())
self._scale.setYScale(sy * self._scale.yScale())
def setRenderHints(self, painter):
painter.setRenderHints(QPainter.SmoothPixmapTransform | QPainter.HighQualityAntialiasing | QPainter.TextAntialiasing)
def boundingRectExtraScale(self):
return (1.2 , 1.2)
def mouseScalingFactors(self, pos, last_pos):
delta = pos - last_pos
return (1.01 ** delta.x(), 1.01 ** delta.y())
def mouseRotationAngle(self, pos, last_pos):
return 1 #TODO
def createDefaultContextMenu(self):
menu = QMenu()
if self._mode == 'neutral':
menu.addAction('Scale').triggered.connect(lambda: self.setMode('scale'))
menu.addAction('Rotate').triggered.connect(lambda: self.setMode('rotate'))
else:
menu.addAction('Done Editing').triggered.connect(lambda: self.setMode('neutral'))
return menu
def contextMenuEvent(self, event):
menu = self.createDefaultContextMenu()
menu.exec(event.screenPos())
def setMode(self, mode):
self._mode = mode
def setSelected(self, selected):
super().setSelected(selected)
self.update()
class ShapedObject(Object):
def __init__(self):
super().__init__()
self._shape = {
'name' : 'ellipse',
'radius': 35
}
self._brush = QBrush(Qt.darkGreen)
self._pen = QPen(Qt.yellow, 3)
def shapeDef(self):
return self._shape
def boundingRect(self):
rect = self.shapeRect()
s = self.boundingRectExtraScale()
return scaleRect(rect, *s)
def shape(self): #TODO QPainterPath shape for collision detection
# Should call self.boundingRectExtraScale()
return super().shape()
def paint(self, painter, option, widget):
self.setRenderHints(painter)
#super().paint(painter, option, widget)
shape = self.shapeDef()
name = shape['name']
painter.setBrush(self._brush)
painter.setPen(self._pen)
painter.save()
path = QPainterPath()
if name == 'ellipse':
r = shape['radius']
path.addEllipse(QPointF(0, 0), r, r)
painter.drawPath(path)
painter.restore()
def shapeRect(self):
shape = self.shapeDef()
name = shape['name']
if name == 'ellipse':
r = shape['radius']
rect = QRectF(-r, -r, 2*r, 2*r)
return rect
####
import sys
from PyQt5.QtWidgets import QMainWindow, QGraphicsScene, QGraphicsView, QApplication
if __name__ == '__main__':
app = QApplication(sys.argv)
window = QMainWindow()
view = QGraphicsView()
scene = QGraphicsScene()
view.setScene(scene)
window.setCentralWidget(view)
ellipse = ShapedObject()
scene.addItem(ellipse)
window.show()
sys.exit(app.exec_())