一旦将某些变量输入到输入字段并单击“绘图”按钮,这将绘制散射角与检测器距离的关系。该图显示在我创建的画布中。绘图方法是“def flup()”,大约是通过单击名为“bgra”的按钮执行的代码的一半。
当我更改输入字段中的变量然后再次点击绘图时,程序会在画布上添加另一个绘图,这很好。我想要做的是添加一个按钮,其命令是清除整个画布。
就在绘图方法“flup()”下面有一个名为 def clear() 的方法的开始,我想在其中定义一个函数,按钮将使用该函数来清除画布。您会注意到,该按钮已在其下方几行创建,称为“删除”。有人可以给我一个示例,说明我需要在 def clear() 方法中包含的一小段代码,以便该按钮可以清除画布。
from numpy import *
import matplotlib.pyplot as plt
fromTkinter import *
import tkMessageBox
from pylab import savefig
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg,NavigationToolbar2TkAgg
import matplotlib.backend_bases
from matplotlib.figure import Figure
def rutherford():
tkMessageBox.showinfo("hello world", j)
def N():
tkMessageBox.showinfo("Variable N", "Number of alpha particles incident on foil")
def T():
tkMessageBox.showinfo('Variable t', 'Thickness of foil in metres')
def K():
tkMessageBox.showinfo('Variable E', 'Kinetic energy of alpha particles in joules')
def atom():
tkMessageBox.showinfo('Variable Z', 'Atomic number of element from which the foil is made, or the name of the element')
class App:
def __init__(self, master):
frame = Frame(master) #creates the first frame
Button(frame, text = "?", command=N).grid(row=1,column=2) #various help buttons
Button(frame, text = "?", command=T).grid(row=2,column=2)
Button(frame, text = "?", command=K).grid(row=3,column=2)
Button(frame, text = "?", command=atom).grid(row=4,column=2)
Nlabel = Label(frame, text = "N =").grid(row=1, column=0, sticky=E) #labels next to the entry frame
tlabel = Label(frame, text="t =").grid(row=2,column=0, sticky=E)
Elabel = Label(frame, text="E =").grid(row=3,column=0, sticky=E)
Zlabel = Label(frame, text="Z =").grid(row=4, column=0, sticky=E)
eN=Entry(frame)
eN.grid(row=1,column=1)
et=Entry(frame)
et.grid(row=2,column=1)
eE=Entry(frame)
eE.grid(row=3,column=1)
eZ=Entry(frame)
eZ.grid(row=4,column=1)
def flup(): #the plot
N=float(eN.get())#turn string into float
t=float(et.get())
E=float(eE.get())
Z=float(eZ.get())
r=10*(10**-10)
e=1.602*(10**-19)
a=5*(10**30)
i = linspace(math.pi/80, math.pi, 1000)
list =[]
for p in i:
b = (N*a*t)/(16.0*(r**2))
c = ((2.0*Z*(e**2))/(E*4.0*math.pi*8.854*(10**-12)))**2
d = (1.0/(math.sin(p/2.0)))**4
n=b*c*d
list.append(n)
f=Figure(figsize=(5,4), dpi=100)
g=f.add_subplot(1,1,1)
g.plot(i,list)
canvas=FigureCanvasTkAgg(f, master=master)
canvas.show()
canvas.get_tk_widget().pack(side=LEFT, fill=BOTH, expand=1)
canvas._tkcanvas.pack(side=TOP, fill=BOTH, expand=1)
#def clear():
bgra=Button(frame, text = "Plot", command=flup) #this button makes the plot
bgra.grid(row=5,column=1)
delete=Button(frame,text='Clear All', command=clear)
delete.grid(row=5,column=2)
frame2=Frame(master)
b1=Button(frame2, text="Rutherford Scattering??", command=rutherford)
b1.pack(side=LEFT)
frame2.pack()
frame.pack()
root = Tk()
app = App(root)
root.mainloop()