from tkinter import *
import math
from R2Graph import *

def func(x):
    return math.sin(2.0*x)*(4.0/(1.0 + 0.2*x*x))

SCALEX = 40
SCALEY = SCALEX

def main():
    root = Tk()
    root.title("Plot Function")
    root.geometry("800x600")
    panel = Frame(root)
    drawArea = Canvas(root, bg="white")
    panel.pack(side=TOP, fill=X)
    drawButton = Button(panel, text="Draw")
    clearButton = Button(panel, text="Clear")
    drawButton.pack(side=LEFT, padx=4, pady=4)
    clearButton.pack(side=LEFT, padx=4, pady=4)
    drawArea.pack(side=TOP, fill=BOTH, expand=True, padx=4, pady=4)
    root.update()
    
    points = []
    mouseButtons = []
    
    def map(t):    
        '''Map mathematical coordinates into pixel coordinates
        R2Point --> (x, y)'''
        w = drawArea.winfo_width()
        h = drawArea.winfo_height()
        ox = w/2.
        oy = h/2.
        return (ox + t.x*SCALEX, oy - t.y*SCALEY)
        
    def invmap(p):    
        '''Map pixel coordinates into mathematical coordinates
        (x, y) --> R2Point'''
        w = drawArea.winfo_width()
        h = drawArea.winfo_height()
        ox = w/2.
        oy = h/2.
        x = float(p[0] - ox)/SCALEX
        y = float(oy - p[1])/SCALEY 
        return R2Point(x, y)

    def xmin():
        w = drawArea.winfo_width()
        return (-w/2.)/SCALEX
    def xmax():
        w = drawArea.winfo_width()
        return (w/2.)/SCALEX
    def ymin():
        h = drawArea.winfo_height()
        return (-h/2.)/SCALEY
    def ymax():
        h = drawArea.winfo_height()
        return (h/2.)/SCALEY
            
    def drawGrid():
        x0 = xmin(); x1 = xmax()
        y0 = ymin(); y1 = ymax()
        # Grid
        for x in range(int(x0), int(x1) + 1):
            if x == 0:
                continue
            drawArea.create_line(
                map(R2Point(x, y0)),
                map(R2Point(x, y1)),
                fill="lightGray"
            )
        for y in range(int(y0), int(y1) + 1):
            if y == 0:
                continue
            drawArea.create_line(
                map(R2Point(x0, y)),
                map(R2Point(x1, y)),
                fill="lightGray"
            )
        # Coordinate axes
        drawArea.create_line(
            map(R2Point(x0, 0.)),         
            map(R2Point(x1, 0.)),
            fill="black", width=2
        )         
        drawArea.create_line(
            map(R2Point(0., y0)),         
            map(R2Point(0., y1)),
            fill="black", width=2
        )
        
    def plotFunc(f):
        line = []
        x = xmin()
        x1 = xmax()
        dx = 0.05
        while x <= x1:
            t = R2Point(x, f(x))         
            line.append(map(t))
            x += dx
        drawArea.create_line(line, fill="blue", width=3)
        
    def drawPoints():
        for i in range(len(points)):
            t = points[i]
            n = mouseButtons[i]
            if n == 1:
                color = "red"
            elif n == 2:
                color = "darkGreen"
            else:
                color = "darkMagenta"
            dx = R2Vector(0.2, 0.)
            drawArea.create_line(
                map(t - dx), map(t + dx), fill=color, width=2
            )            
            dy = R2Vector(0., 0.2)
            drawArea.create_line(
                map(t - dy), map(t + dy), fill=color, width=2
            )            

    
    def onDraw():
        drawArea.delete("all")
        drawGrid()
        plotFunc(func)
        drawPoints()    

    def onClear():
        points.clear()
        mouseButtons.clear()
        drawArea.delete("all")
        drawGrid()
        
    drawButton.configure(command = onDraw)
    clearButton.configure(command = onClear)
    
    def onClick(e):
        # print(e)
        p = (e.x, e.y)
        t = invmap(p)
        points.append(t)
        mouseButtons.append(e.num)
        if e.num == 1:
            color = "red"
        elif e.num == 2:
            color = "darkGreen"
        else:
            color = "darkMagenta"
        dx = R2Vector(0.2, 0.)
        drawArea.create_line(
            map(t - dx), map(t + dx), fill=color, width=2
        )            
        dy = R2Vector(0., 0.2)
        drawArea.create_line(
            map(t - dy), map(t + dy), fill=color, width=2
        )
        
    def onConfigure(e):
        onDraw()            

    drawArea.bind("<Button-1>", onClick)
    drawArea.bind("<Button-2>", onClick)
    drawArea.bind("<Button-3>", onClick)
    drawArea.bind("<Configure>", onConfigure)

    drawGrid()
    plotFunc(func)
            
    root.mainloop()

if __name__ == "__main__":
    main()