# Tk_Paint_Demo.py

# Tk_Paint_Demo.py

import tkinter as tk
import tkinter.ttk as ttk

COLORS = '''
black
gray
light gray
white
navy
medium blue
royal blue
blue
deep sky blue
sky blue
light sky blue
light blue
turquoise
cyan
aquamarine
dark green
lawn green
forest green
khaki
yellow
gold
indian red
orange
dark orange
red
pink
light pink
maroon
purple
medium purple
'''.splitlines()[1:-1]

GRAYS = '''
gray1
gray2
gray3
gray4
gray5
gray6
gray7
gray8
gray9
gray10
gray11
gray12
gray13
gray14
gray15
gray16
gray17
gray18
gray19
gray20
gray21
gray22
gray23
gray24
gray25
gray26
gray27
gray28
gray29
gray30
gray31
gray32
gray33
gray34
gray35
gray36
gray37
gray38
gray39
gray40
gray42
gray43
gray44
gray45
gray46
gray47
gray48
gray49
gray50
gray51
gray52
gray53
gray54
gray55
gray56
gray57
gray58
gray59
gray60
gray61
gray62
gray63
gray64
gray65
gray66
gray67
gray68
gray69
gray70
gray71
gray72
gray73
gray74
gray75
gray76
gray77
gray78
gray79
gray80
gray81
gray82
gray83
gray84
gray85
gray86
gray87
gray88
gray89
gray90
gray91
gray92
gray93
gray94
gray95
gray97
gray98
gray99
'''.splitlines()[1:-1]

class DrawApp(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title("Tk Paint Demo")
        self._xold = None
        self._yold = None
        self.canvas = None
        self.color = "Black"
        self.thickness = 1
        self.tag = ["tag", "0"] #Don't know why but tags can't be just a number
        self._create_widgets()

    def _create_widgets(self):
        topframe = tk.Frame(self)
        topframe.grid(row=0, column=0, pady=10)

        self.col_select = tk.StringVar()
        colorList = ttk.Combobox(topframe, textvariable=self.col_select, values=COLORS, state="readonly", width=10)
        colorList.current(0)
        self.option_add('*TCombobox*Listbox.selectBackground', 'skyblue')
        colorList.bind('<<ComboboxSelected>>', self._change_color)
        colorList.grid(row=0, column=0, padx=5)

        self.t_select = tk.StringVar()
        tList = ttk.Combobox(topframe, textvariable=self.t_select, values=[1, 2, 3, 4, 5, 6, 7, 8, 9, 10], state="readonly", width=2)
        tList.current(0)
        tList.bind('<<ComboboxSelected>>', self._change_thickness)
        tList.grid(row=0, column=1, padx=5)

        tk.Button(topframe, text="Undo", bg="blue", fg="white", activebackground="blue4", activeforeground="white", command=self._undo).grid(row=0, column=2, padx=5)
        tk.Button(topframe, text="Clear", bg="brown", fg="white", activebackground="brown4", activeforeground="white", command=self._clear).grid(row=0, column=3, padx=5)
        self.canvas = tk.Canvas(self, width=400, height=400, bg='white')
        self.canvas.grid(row=1, column=0, padx=10, pady=(0,10))
        self.canvas.bind("<ButtonRelease-1>", self._on_up)
        self.canvas.bind("<B1-Motion>", self._on_motion)

    def _change_color(self, event=None):
        self.color = self.col_select.get()

    def _change_thickness(self, event=None):
        self.thickness = int(self.t_select.get())

    def _clear(self):
        self.canvas.delete("all")
        self.tag = ["tag", "0"]

    def _undo(self):
        cur_tag = int(self.tag[1])
        if cur_tag >= 1:
            self.canvas.delete("tag"+str(cur_tag-1))
            self.tag = ["tag", str(cur_tag - 1)]

    def _on_up(self, event):
        self._xold = None
        self._yold = None
        self.tag = ["tag", str(int(self.tag[1])+1)]

    def _on_motion(self, event):
        tag = "".join(self.tag)
        x1, y1 = (event.x - self.thickness), (event.y - self.thickness)
        x2, y2 = (event.x + self.thickness), (event.y + self.thickness)
        event.widget.create_oval(x1, y1, x2, y2, width=0, fill=self.color, tag=tag)
        if self._xold is not None and self._yold is not None:
            self.canvas.create_oval(x1, y1, x2, y2, width=0, fill=self.color, tag=tag)
            self.canvas.create_line(self._xold, self._yold, event.x, event.y, smooth=True, width=2*self.thickness, fill=self.color, tag=tag)
    # here's where you draw it. smooth. neat.
        self._xold = event.x
        self._yold = event.y

DrawApp().mainloop()