我试图使用QGraphics变换矩阵进行平移和缩放。缩放可以正常工作，但是平移参数m31和m32没有效果。看起来还有另一个函数会将场景居中。在下面的代码中，我操作rectScene以执行平移，但为什么不能使用m31和m32进行平移呢？（这是我的问题）
'''Pan (left mouse but) and zoom (mouse wheel) test'''
'''Python 3.4 (No differance between PyQt4 and PyQt5)'''
#from PyQt5 import QtGui, QtCore
#import PyQt5.QtWidget as QW
from PyQt4 import QtGui, QtCore
import PyQt4.QtGui as QW
import numpy as np
class ZoomAndPan(QW.QGraphicsView):
def __init__(self,parent=None):
super(ZoomAndPan,self).__init__(parent)
self.setWindowTitle('ZoomAndPan')
self.setGeometry(600,300,600,400)
'Left button in top of image. Shows the transform matrix (press to reset)'
self.mess = QW.QPushButton('Transform Matrix\n\n\ndx,xy\ncounter', self)
self.mess.clicked.connect(self.resetM)
'm31 button, adds 200 to m31'
self.m31 = QW.QPushButton('m31', self)
self.m31.move(200,0)
self.m31.clicked.connect(self.addM31)
'm13 button, adds 0.0001 to m13'
self.m13 = QW.QPushButton('m13', self)
self.m13.move(300,0)
self.m13.clicked.connect(self.addM13)
self.count=0 #Counter
# Create scene
self.sc=scene(self,self)
self.setScene(self.sc)
def mouseMoveEvent(self,event):
'Pan by manipulting sceneRect'
pos=event.pos()
pos=self.mapToScene(pos)
dx=pos.x()-self.sc.startPos.x()
dy=pos.y()-self.sc.startPos.y()
rect=self.sceneRect().getRect()
self.setSceneRect(rect[0]-dx,rect[1]-dy,rect[2],rect[3])
# Increas counter to show that the loop works
self.count+=1
self.showMatrix()
def showMatrix(self):
'Show matrix in Textbox (Buttton)'
m=self.transform()
str1='{0:5.2f}{1:5.2f} {2:6.4f}\n'.format(m.m11(), m.m12(),m.m13())
str2='{0:5.2f}{1:5.2f}{2:5.2f}\n'.format(m.m21(), m.m22(),m.m23())
str3='{0:5.2f}{1:5.2f}{2:5.2f}\n'.format(m.m31(), m.m32(),m.m33())
str4='{0:5.2f}{1:5.2f}\n'.format(m.dx(), m.dy(),m.m33())
'Show counter '
str5='{0:5.0f}'.format(self.count)
self.mess.setText(str1+str2+str3+str4+str5)
def resetM(self):
'Reset transform'
self.resetTransform()
self.showMatrix()
def addM31(self):
'Add 200 to m31 '
m=self.transform()
m.setMatrix(m.m11(),m.m12(),m.m13(),m.m21(),m.m22(),m.m23(),m.m31()+200,m.m32(),m.m33())
self.setTransform(m)
self.showMatrix()
def addM13(self):
'Add 0.0001 to m13 '
m=self.transform()
m.setMatrix(m.m11(),m.m12(),m.m13()+0.0001,m.m21(),m.m22(),m.m23(),
m.m31(),m.m32(),m.m33())
self.setTransform(m)
self.showMatrix()
class scene(QW.QGraphicsScene):
def __init__(self,parent,myView=[]):
QW.QGraphicsScene.__init__(self,parent)
self.myView=myView
# Some items in scene
self.txt=self.addSimpleText("///////")
self.txt.setPos(2,-20)
self.txt.setScale(2)
self.txt.setBrush(QtGui.QBrush(QtCore.Qt.green))
self.addRect(0,16,20,20, pen=QtGui.QPen(QtCore.Qt.blue))
self.addRect(10,60,32,8, pen=QtGui.QPen(QtCore.Qt.red))
self.addRect(30,16,20,20, pen=QtGui.QPen(QtCore.Qt.blue))
self.N=0
def mousePressEvent(self, event):
self.myView.setDragMode(1) # Works fine without this
self.startPos=event.scenePos()
def mouseReleaseEvent(self, event):
self.myView.setDragMode(0)
def wheelEvent(self, event):
'zoom'
sc=event.delta()/100
if sc<0: sc=-1/sc
self.myView.scale(sc,sc)
self.myView.setDragMode(0)
self.myView.showMatrix()
def main():
app = QW.QApplication([])
fig=ZoomAndPan()
fig.show();
app.exec_()
if __name__=='__main__':
main()