如何在PyQt中編寫非常基本的基於節點的編輯器？

Question

我想實現一個簡單的節點接口，其中節點執行其輸入連接的總和，並輸出結果。

實施例：http://i.stack.imgur.com/h0l6N.png

只是一段簡單的功能的代碼。

Answer 1

這應該是完全可能的。

我建議你爲盒子生成新的QLineEdits（你可以給他們一個使用Qt樣式表的盒子）。然後，您將能夠解析通過Python中的輸入。我會建議你閱讀this question on draggable buttons。你應該能夠適應qlineedit。我也會建議你一般對鼠標事件非常熟悉。

連接器可能是QWidgets，您可以在小部件上定義自定義paintEvent以繪製直線和圓。

編輯：這實際上是我感興趣的東西，所以我想我會掀起一個例子。

EDIT3：嗯，我有一些樣本可活動塊：

import sys, time 
from PyQt4.QtCore import * 
from PyQt4.QtGui import * 
from PyQt4.QtCore import Qt 

class Entry(QLineEdit): 
    def __init__(self,parent=None): 
     QLineEdit.__init__(self,parent) 
     self.resize(75,50) 
    def paintEvent(self,event): 
     painter=QPainter() 
     painter.begin(self) 
     painter.setRenderHint(QPainter.HighQualityAntialiasing) 
     painter.setRenderHint(QPainter.SmoothPixmapTransform) 
     painter.drawEllipse(54,25,20,20) 
     painter.drawRect(QRect(0,0,self.width()-22,self.height()-1)) 
     font=QFont('Arial',13) 
     painter.setFont(font) 
     painter.drawText(QPoint(22,22),self.text()) 
     painter.end() 
     #movements from https://stackoverflow.com/questions/12219727/dragging-moving-a-qpushbutton-in-pyqt 
    def mousePressEvent(self, event): 
     self.__mousePressPos = None 
     self.__mouseMovePos = None 
     if event.button() == Qt.LeftButton: 
      self.__mousePressPos = event.globalPos() 
      self.__mouseMovePos = event.globalPos()   
     super(Entry, self).mousePressEvent(event) 
    def mouseMoveEvent(self, event): 
     if event.buttons() == Qt.LeftButton: 
      # adjust offset from clicked point to origin of widget 
      currPos = self.mapToGlobal(self.pos()) 
      globalPos = event.globalPos() 
      diff = globalPos - self.__mouseMovePos 
      newPos = self.mapFromGlobal(currPos + diff) 
      self.move(newPos) 
      self.__mouseMovePos = globalPos 
     super(Entry, self).mouseMoveEvent(event) 
    def mouseReleaseEvent(self, event): 
     if self.__mousePressPos is not None: 
      moved = event.globalPos() - self.__mousePressPos 
      if moved.manhattanLength() > 3: 
       event.ignore() 
       return 
     super(Entry, self).mouseReleaseEvent(event) 
class Add(QWidget): 
    def __init__(self,parent=None): 
     QWidget.__init__(self,parent) 
     self.resize(75,50) 
    def paintEvent(self, event): 
     #use QPainter for a custom look 
     painter=QPainter() 
     painter.begin(self) 
     painter.setRenderHint(QPainter.HighQualityAntialiasing) 
     painter.setRenderHint(QPainter.SmoothPixmapTransform) 
     painter.drawEllipse(0,25,20,20) 
     painter.drawEllipse(0,0,20,20) 
     painter.drawRect(QRect(20,0,34,49)) 
     painter.drawEllipse(53,24,20,20) 
     font=QFont('Arial',13) 
     painter.setFont(font) 
     painter.drawText(QPoint(22,22),"Add") 
     painter.end() 
    #movements from https://stackoverflow.com/questions/12219727/dragging-moving-a-qpushbutton-in-pyqt 
    def mousePressEvent(self, event): 
     self.__mousePressPos = None 
     self.__mouseMovePos = None 
     if event.button() == Qt.LeftButton: 
      self.__mousePressPos = event.globalPos() 
      self.__mouseMovePos = event.globalPos() 
     super(Add, self).mousePressEvent(event) 
    def mouseMoveEvent(self, event): 
     if event.buttons() == Qt.LeftButton: 
      # adjust offset from clicked point to origin of widget 
      currPos = self.mapToGlobal(self.pos()) 
      globalPos = event.globalPos() 
      diff = globalPos - self.__mouseMovePos 
      newPos = self.mapFromGlobal(currPos + diff) 
      self.move(newPos) 
      self.__mouseMovePos = globalPos 
     super(Add, self).mouseMoveEvent(event) 
    def mouseReleaseEvent(self, event): 
     if self.__mousePressPos is not None: 
      moved = event.globalPos() - self.__mousePressPos 
      if moved.manhattanLength() > 3: 
       event.ignore() 
       return 
     super(Add, self).mouseReleaseEvent(event) 
class Window(QMainWindow): 
    def __init__(self): 
     QMainWindow.__init__(self) 
     self.resize(640,480) 
     self.add=Add(self) 
     self.entry1=Entry(self) 
     self.entry2=Entry(self) 
if __name__=="__main__": 
    app=QApplication(sys.argv) 
    win=Window() 
    win.show() 
    sys.exit(app.exec_()) 

注意，沒有連接部件。我會根據鼠標按鍵繪製自定義小部件（例如，某人按下輸入終端，然後添加）。另請注意，Entry塊沒有明確的方式表示有條目。你可以連接一個Qtimer並在文本閃爍的下方有一行。