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我已经（在我的好友@Nuclearman 的帮助下回答了我的其他问题之一）在我的程序中部分实现了重做功能，这是一个海龟图形程序，可以将用户按下的键盘上的任何字母绘制到海龟上图形画布。我说“部分”是因为虽然它确实重做，但它并没有做它的本意，如果用户调用一个新字母，它会用一个新字母覆盖最后一个未完成的字母。例如，假设您在画布上写了“HELLO”并取消了“H”。然后，您想用“A”替换“E”。所以你画一个“A”。当您按重做时，它现在应该显示“HAL”对吗？好吧，我的重做不是这种情况。我的重做，按照我给出的例子，输出这个：

有...

它将 E 绘制在 A 之上！好吧，这不是重做的目的！那么，我怎样才能使乌龟绘制“HAL”而不是上图中发生的任何事情，并根据我当前的重做函数实现它，如下所示？任何帮助是极大的赞赏！:)

我的重做功能：

def Clear():
    # Clear the canvas
    clear()
    speed(0)
    tracer(0,0)

def redoHandler():
    if undoHandler.handling == True and draw.drawing == True and len(newerdeq) > 0:
        # "newerdeq" is my 'forward' stack for the redo to be possible
        redoHandler.handling = True
        if not hasattr(redoHandler, "counter"):
            redoHandler.counter = 0
        redoHandler.counter += 1
        draw.counter += 1
        print("`draw` has been called {} times.".format(draw.counter))
        Clear()
        ui = newerdeq.pop() #<-- Pop redone items...
        function.append(ui) #<-- back to the "undo" function stack.
        penup()
        try:
            goto(o,p)
        except:
            goto(-200, 100)
        pendown()

        try:
            # Now execute all the items (from an earlier queue that all letter functions go to first) if defined as a Point class or as a function
            for i in function:
            k = i.getXY()
            penup()
            goto(k)
            pendown()
            hk = i.getletterheight()
            global letter_height
            letter_height = hk
            rk = i.getletterwidth()
            global letter_width
            letter_width = rk
            hw = i.getwidth()
            width(hw)
            op = i.getcolor()
            try:
                color(op)
            except:
                for g in colors:
                    cp = g.getcolor2()
                    colormode(255)
                    color(cp)
            j = i.getfunction()
            j()
        except:
            i()



    update()
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1 回答 1

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嗯，我解决了。这是一个非常简单的修复。我所要做的就是在执行每个字母的队列中，只需输入：

if len(newerdeq) > 0:
    newerdeq.pop()

像这样：

def draw(x):
draw.drawing = True
if not hasattr(draw, 'counter'):
     draw.counter = 0
global drawing
q.put(x)
process = False
drawingLock.acquire()
if not drawing:
    process = True
    drawing = True
drawingLock.release()
if process:
    if not q.empty():
        v = xcor()
        y = ycor()
        c = pencolor()
        w = width()
        ph = letter_height
        pw = letter_width
        x()
        po = Point(v,y,c,w,isdown(),x,ph,pw)
        function.append(po)
        if len(newerdeq) > 0:
           newerdeq.pop() #<-- Here it is... fixed.
        draw.counter += 1
        print("`draw` has been called {} times.".format(draw.counter))
        if x == draw_W:
            draw_W.drawing = True
            draw_W.counter += 1
            draw.counter -= 1
        elif x == draw_Y:
            draw_Y.drawing = True
            draw_Y.counter += 1
            draw.counter -= 1
        global h
        h = (x) 
    drawingLock.acquire()
    drawing = False
    drawingLock.release()
于 2016-01-07T09:04:35.857 回答