Question

我正在尝试创建小型GUI应用程序，用户可以在其中绘制点和曲线。我实施了比例选项。

我想仅缩放路径，而不是缩放点的图形表示（RBNode类）。除了RBNode类之外，有没有办法扩展QGraphicsView？

我目前的方法是将RBGraphicView类（继承自QGraphicsView）中的wheelEvent方法中创建的因子属性传递到RBNode的实例中，并使用它重绘RBNode。

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sys
import math
from PySide.QtGui import *
from PySide.QtCore import *


class RBNode(QGraphicsItem):
    def __init__(self, factorView = 1):
        super(RBNode, self).__init__()
        self.factor = factorView
        self.pressed = False
        self.x = self.pos().x()
        self.y = self.pos().y()
        self.setFlag(QGraphicsItem.ItemIsMovable)

    def boundingRect(self):
        self.update()
        return QRectF(-5*self.factor,-5*self.factor,10*self.factor,10*self.factor)


    def paint(self, painter, option, widget):
        self.update()
        rect = QRectF(-5*self.factor,-5*self.factor,10*self.factor,10*self.factor)

        if self.pressed:
            painter.setBrush(Qt.red)
        else:
            painter.setBrush(Qt.darkGray)

        painter.drawEllipse(rect)

    def mousePressEvent(self, event):
        self.pressed = True
        self.update()
        QGraphicsItem.mousePressEvent(self,event)

    def mouseReleaseEvent(self, event):
        self.pressed = False
        self.update()
        QGraphicsItem.mouseReleaseEvent(self,event)


class RBGraphicView(QGraphicsView):
    def __init__(self):
        super(RBGraphicView, self).__init__()
        self.factorView = 1
        self.initScene()
        self.initGui()



    def initGui(self):
        self.setWindowTitle("A Simple Animation")
        self.show()

    def initScene(self):
        self.rbScene = QGraphicsScene(self)
        self.rbAddItem(self.rbScene)
        self.setScene(self.rbScene)

    def wheelEvent(self, event):
        factor = math.pow(2.0, -event.delta() / 240.0)
        self.scaleView(factor)

    def scaleView(self, scaleFactor):
        factor = self.matrix().scale(scaleFactor, scaleFactor).mapRect(QRectF(0,0,1,1)).width()
        if factor < 0.001 or factor > 1000:
            return
        self.scale(scaleFactor, scaleFactor)
        self.factorView = factor


    def rbAddItem(self, scene):

        rbNode1 = RBNode(self.factorView)
        rbNode1.setPos(100,100)

        rbNode2 = RBNode()
        rbNode2.setPos(100,100)

        rbP2 = QPointF(20.0, 10.0)
        rbP3 = QPointF(80.0, 30.0)
        rbP4 = QPointF(90.0, 70.0)
        bezierPath = QPainterPath()
        bezierPath.moveTo(rbNode1.x, rbNode1.y)
        bezierPath.cubicTo(rbP2.x(),rbP2.y(),rbP3.x(),rbP3.y(),rbP4.x(),rbP4.y())
        myItem = QGraphicsPathItem(bezierPath)

        scene.addItem(rbNode1)
        scene.addItem(rbNode2)
        scene.addItem(myItem)

if __name__ == '__main__':
    try:
        myApp = QApplication(sys.argv)
        myView = RBGraphicView()
        myApp.exec_()
        sys.exit(0)

    except NameError:
        print("Name Error:", sys.exc_info()[1])

    except SystemExit:
        print("Closing Window...")

    except Exception:
        print(sys.exc_info()[1])

PySide / PyQt：在缩放QGraphicsView

0 个答案: