绘制程序使用临时文件撤销重做功能？

Question

我正在使用撤销重做功能创建绘图程序。我通过拍摄画布快照并将它们保存为jpeg文件来实现它。然后，我将文件的名称添加到列表中以供稍后获取。我如何使这些jpeg文件临时？我应该使用什么模块？我正在使用Python 3.2.5。感谢您的帮助！

下面是一些我的代码

if mb[0]==0 and count==1:      #if a drawing was made 
      count1+=1         #my filename assigner 
      fileName=str(count1)+".jpg"     #creates fileName 
      image.save(screen.subsurface(touch),fileName)#saves image 
      nowlist.append(fileName)     #adds to nowlist 
      count=0          #resets counter 
      if len(nowlist)>1:       #removes old data 
       undolist.append(nowlist[0])    #adds it to undolist 
       del(nowlist[0])       #dels it 
      print("nowlist :",nowlist)     #prints lists 
      print("undolist :",undolist) 
    if undoRect.collidepoint((mx,my)) and mb[0]==1: #if mouse is over and clicks undo 
     if len(undolist)>0:       #if there are at least 1 item 
      fileName=undolist[-1]     #last item of undolist 
      canvas1=image.load(fileName)   #fetch file image 
      canvas2=screen.blit(canvas1,[150,150]) #blit it onto the canvas 
      nowlist.append(fileName)    #adds it to the canvas list 
      if len(nowlist)>1:      #ensures there is only 1 item on the canvas 
       redolist.append(nowlist[0]) 
       del(nowlist[0])        
      del(undolist[-1])      
      print("nowlist :",nowlist)    
      print("undolist :",undolist)   #prints undolist 
      print("redolist :",redolist)   #prints redolist 
    if redoRect.collidepoint((mx,my)) and mb[0]==1: #if mouse is over and clicks redo 
     if len(redolist)>0:       #if there is at least 1 item 
      fileName=redolist[-1]     #take last term 
      canvas1=image.load(fileName)   #fetch file of that name 
      canvas2=screen.blit(canvas1,[150,150]) #blit it onto the canvas 
      nowlist.append(fileName)    #append it to the nowlist, 
      if len(nowlist)>1:      #removes what was on the canvas 
       undolist.append(nowlist[0])   #adds it to the undo list 
       del(nowlist[0])      #del from nowlist 
      del(redolist[-1])      
      print("nowlist :",nowlist)    #prints the lists  
      print("undolist :",undolist) 
      print("redolist :",redolist) 

Answer 1

请参阅制作临时文件和目录的临时文件模块。

至于撤消，首先考虑在文本编辑器中撤销/重做。对于每个文本更改，都会有一个反向更改来解除更改。这些是你保存的内容，而不是整个文件的快照。对于大块更改，撤消可能比典型的“差异”更紧凑。对于块替换（例如用粘贴代替选择时执行的块），块开始和旧文本需要保存，但仅保存新文本的长度。当执行这种撤消操作时，可以通过从正在恢复的文本缓冲区中检索新文本，将其变为重做。必须决定是否允许“无限”撤销（直到内存用完）或设置固定限制。对于二维图形，设置（（x，y），get（x，y））撤销设置（（x，y），颜色）。除此之外，由于像素数量远大于字符及其平面而不是线性组织，事情往往会更复杂。但是上述原则仍然适用。