import tkinter as tk
import math

x = 20
y = 20
z = -20

def nextPoint():
    global x,y,z,app

    x = x + 3
    y = y + 2
    z = z + 0.5

    print(x,y,z)

    app.drawPoint(x,y,z)

class Application(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.pack()
        self.createWidgets()
        self.x=20
        self.y=20
        self.z=-2

        self.maxDepth = -20

    def createWidgets(self):
        self.canvas = tk.Canvas(self, bg="black", height=640, width=800)
        #arc = self.canvas.create_arc(coord, start=0, extent=150, fill="red")
        self.canvas.pack()

        self.createPoint = tk.Button(self, text="Create point", fg="black", command=nextPoint)
        self.createPoint.pack(side="bottom")

        self.QUIT = tk.Button(self, text="QUIT", fg="black", command=root.destroy)
        self.QUIT.pack(side="bottom")

    def incrementHex(self, hex_str, increment): #with hex_str in format "#FFFFFF" or any colour
        red = int(hex_str[1:3],16) #specifies base for integer conversion
        green = int(hex_str[3:5],16)
        blue = int(hex_str[5:],16)
        red += increment #increment can be negative
        green += increment
        blue += increment

        print(str(hex(red)))

        if len(str(hex(red))[2:4]) < 2:
            new_hex_str = "#0" + str(hex(red))[2:4] + "0000"
        else :
            new_hex_str = "#" + str(hex(red))[2:4] + "0000"
        return new_hex_str

    def drawPoint(self, x, y, z):
        self.canvas.create_oval(x-2, y-2, x+2, y+2, fill=self.incrementHex("#000000", round((z/self.maxDepth)*255)))

root = tk.Tk()
app = Application(master=root)

app.mainloop()