Tkinter在单击时获取鼠标坐标并将其用作变量

Question

我对Python完全不熟悉。所以不要太生我的气，因为我确信我遗漏了一些基本的东西。这是我的问题：

我正在尝试从图像中提取鼠标单击坐标，并将这些坐标用作变量。

代码允许导入和图像，我想从中提取坐标。一些提示询问用户图表的大小和范围，然后我想通过单击原点和x轴和y轴上的终点来设置坐标网格。其思想是使用这3组坐标，并通过一些转换函数（见代码）将它们转换为压力和温度坐标。

# Determine the origin by clicking
# Probably with classes??
class Origin:
    def getorigin(eventorigin):
          eventorigin.x0 = eventorigin.x
          eventorigin.y0 = eventorigin.y
    #mouseclick event
    w.bind("<Button 1>",getorigin)
# What do I do here??
x0 = ...
y0 = ...

我真的不知道如何将通过单击获得的坐标分配给一个新变量，我可以在后面的代码中使用它。

我可以打印坐标，但是因为它们是一个函数，所以它们是局部的，在函数之外是不可用的（据我所知）。所以，使用类的方法可能更好，但我不知道如何做到这一点。

如有任何帮助，我们将不胜感激。

完整代码（改编）：

from tkinter import *
from tkinter.filedialog import askopenfilename
from PIL import Image, ImageTk
import tkinter.simpledialog

root = Tk()

#setting up a tkinter canvas
w = Canvas(root, width=1000, height=1000)
w.pack()

#adding the image
File = askopenfilename(parent=root, initialdir="./",title='Select an image')
original = Image.open(File)
original = original.resize((1000,1000)) #resize image
img = ImageTk.PhotoImage(original)
w.create_image(0, 0, image=img, anchor="nw")

#ask for pressure and temperature extent
xmt = tkinter.simpledialog.askfloat("Temperature", "degrees in x-axis")
ymp = tkinter.simpledialog.askfloat("Pressure", "bars in y-axis")

#ask for real PT values at origin
xc = tkinter.simpledialog.askfloat("Temperature", "Temperature at origin")
yc = tkinter.simpledialog.askfloat("Pressure", "Pressure at origin")

#instruction on 3 point selection to define grid
tkinter.messagebox.showinfo("Instructions", "Click: \n" 
                                            "1) Origin \n"
                                            "2) Temperature end \n"
                                            "3) Pressure end")

# From here on I have no idea how to get it to work...

# Determine the origin by clicking
def getorigin(eventorigin):
    global x0,y0
    x0 = eventorigin.x
    y0 = eventorigin.y
    print(x0,y0)
#mouseclick event
w.bind("<Button 1>",getorigin)

# Determine the extent of the figure in the x direction (Temperature)
def getextentx(eventextentx):
    global xe
    xe = eventextentx.x
    print(xe)
#mouseclick event
w.bind("<Button 1>",getextentx)

# Determine the extent of the figure in the y direction (Pressure)
def getextenty(eventextenty):
    global ye
    ye = eventextenty.y
    print(ye)
#mouseclick event
w.bind("<Button 1>",getextenty)

#message to confirm that the grid is set up
tkinter.messagebox.showinfo("Grid", "Grid is set. You can start picking coordinates.")

#Coordinate transformation into Pressure-Temperature space
def printcoords(event):
    xmpx = xe-x0
    xm = xmt/xmpx
    ympx = ye-y0
    ym = -ymp/ympx

    #coordinate transformation
    newx = (event.x-x0)*(xm)+xc
    newy = (event.y-y0)*(ym)+yc

    #outputting x and y coords to console
    print (newx,newy)
#mouseclick event
w.bind("<Button 1>",printcoords)

root.mainloop()

Answer 1

如果我在上一条评论中说的是你想做的，因为tkinter不会暂停程序等待鼠标单击事件，你必须这样做：每次单击鼠标按钮时它都会重新绑定它

from tkinter import *
from tkinter.filedialog import askopenfilename
from PIL import Image, ImageTk
import tkinter.simpledialog

root = Tk()

#setting up a tkinter canvas
w = Canvas(root, width=1000, height=1000)
w.pack()

#adding the image
File = askopenfilename(parent=root, initialdir="./",title='Select an image')
original = Image.open(File)
original = original.resize((1000,1000)) #resize image
img = ImageTk.PhotoImage(original)
w.create_image(0, 0, image=img, anchor="nw")

#ask for pressure and temperature extent
xmt = tkinter.simpledialog.askfloat("Temperature", "degrees in x-axis")
ymp = tkinter.simpledialog.askfloat("Pressure", "bars in y-axis")

#ask for real PT values at origin
xc = tkinter.simpledialog.askfloat("Temperature", "Temperature at origin")
yc = tkinter.simpledialog.askfloat("Pressure", "Pressure at origin")

#instruction on 3 point selection to define grid
tkinter.messagebox.showinfo("Instructions", "Click: \n" 
                                            "1) Origin \n"
                                            "2) Temperature end \n"
                                            "3) Pressure end")

# From here on I have no idea how to get it to work...

# Determine the origin by clicking
def getorigin(eventorigin):
    global x0,y0
    x0 = eventorigin.x
    y0 = eventorigin.y
    print(x0,y0)
    w.bind("<Button 1>",getextentx)
#mouseclick event
w.bind("<Button 1>",getorigin)

# Determine the extent of the figure in the x direction (Temperature)
def getextentx(eventextentx):
    global xe
    xe = eventextentx.x
    print(xe)
    w.bind("<Button 1>",getextenty)

# Determine the extent of the figure in the y direction (Pressure)
def getextenty(eventextenty):
    global ye
    ye = eventextenty.y
    print(ye)
    tkinter.messagebox.showinfo("Grid", "Grid is set. You can start picking coordinates.")
    w.bind("<Button 1>",printcoords)

#Coordinate transformation into Pressure-Temperature space
def printcoords(event):
    xmpx = xe-x0
    xm = xmt/xmpx
    ympx = ye-y0
    ym = -ymp/ympx

    #coordinate transformation
    newx = (event.x-x0)*(xm)+xc
    newy = (event.y-y0)*(ym)+yc

    #outputting x and y coords to console
    print (newx,newy)

root.mainloop()

Answer 2

最简单的方法是将x，y设置为global，class或not无关紧要。 我没有看到你的完整代码，因为我无法打开手机上的zip文件。下面是我可以帮助你的例子

import tkinter as tk
def getorigin(eventorigin):
      global x,y
      x = eventorigin.x
      y = eventorigin.y
      print(x,y)

root = tk.Tk()
root.bind("<Button 1>",getorigin)