【发布时间】：2014-06-07 02:55:35
【问题描述】：
我是来自外部世界的学生，之前没有任何编程经验。我一直在学习 Python 作为我数学课的延伸。我一直在尝试创建一个使用 Tkinter 生成分形的程序。代码本身运行良好，但包含用户输入 GUI 会导致错误：
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python33\lib\tkinter\__init__.py", line 1475, in __call__
return self.func(*args)
File "C:\Python33\FractalGUI.py", line 74, in fractals
canvas.create_image((0, 0), image = img, state = "normal", anchor = tkinter.NW)
File "C:\Python33\lib\tkinter\__init__.py", line 2319, in create_image
return self._create('image', args, kw)
File "C:\Python33\lib\tkinter\__init__.py", line 2310, in _create
*(args + self._options(cnf, kw))))
_tkinter.TclError: image "pyimage1" doesn't exist
代码本身如下。请注意，在运行canvas.create_image 行之前不会出现错误。如果我可以提供任何其他信息，请告诉我。谢谢！ :)
import tkinter
from tkinter import *
#Creates widgets for user input
class Imagespecs(Frame):
def __init__(self,master):
Frame.__init__(self,master)
self.grid()
self.y_axis()
self.x_axis()
#Y axis input
def y_axis(self):
self.instruction = Label(self,text = "How many pixels high do you want the image?")
self.instruction.grid(row = 8, column = 0, columnspan = 2, sticky = N)
self.height = Entry(self)
self.height.grid(row = 10, column = 1, sticky = E)
#Enters info to run fractal generation
self.submit_button = Button(self,text = "Submit", command = self.fractals)
self.submit_button.grid(row = 14, column = 2, sticky = E)
#X axis input
def x_axis(self):
self.instruction2 = Label(self,text = "How many pixels wide do you want the image?")
self.instruction2.grid(row = 4, column = 0, columnspan = 2, sticky = E)
self.width = Entry(self)
self.width.grid(row = 6, column = 1, sticky = E)
#generates fractal
def fractals(self):
#Replace non-input
content = self.width.get()
content2 = self.height.get()
if content == "":
content = 500
if content2 == "":
content2 = 500
#Create window specs
WIDTH = int(content2); HEIGHT = int(content)
xa = -2.0; xb = 1.0
ya = -1.5; yb = 1.5
maxIt = 256
window = Tk()
canvas = Canvas(window, width = WIDTH, height = HEIGHT, bg = "#000000")
img = PhotoImage(width = WIDTH, height = HEIGHT)
#The Newton-Raphson iteration
h = HEIGHT
for ky in range(HEIGHT):
print (h)
h = h - 1
for kx in range(WIDTH):
c = complex(xa + (xb - xa) * kx / WIDTH, ya + (yb - ya) * ky / HEIGHT)
z = complex(0.0, 0.0)
for i in range(maxIt):
z = z * z + c
if abs(z) >= 2.0:
break
rd = hex(i % 4 * 64)[2:].zfill(2)
gr = hex(i % 8 * 32)[2:].zfill(2)
bl = hex(i % 16 * 16)[2:].zfill(2)
img.put("#" + rd + gr + bl, (kx, ky))
canvas.create_image((0, 0), image = img, state = "normal", anchor = tkinter.NW)
#Run GUI
canvas.pack()
mainloop()
root = Tk()
root.title("Fractal GUI")
root.geometry("300x200")
app = Imagespecs(root)
root.mainloop()
【问题讨论】：
-
部分问题是您创建了不止一次的
Tk实例。 Tkinter 的设计使得Tk的实例应该只有一次。您的代码似乎也有一些缩进错误。 -
好的，谢谢！我会仔细检查缩进。您知道解决 Tk 问题的方法吗？同时我会尝试修复它，但如果您已经有解决方案，我将不胜感激。 :)
-
如果您需要多个窗口，请使用
Tk创建第一个窗口，然后其余的需要是Toplevel的实例。 -
好的，谢谢！ :) 现在两个窗口都打开了，但它告诉我全局名称 tkinter 没有定义……我会在完成 Bio 课后做更多的工作。感谢您对初学者的所有帮助和耐心。
标签： canvas tkinter python-3.3 fractals