import PySimpleGUI as g
import matplotlib
matplotlib.use('TkAgg')
from numpy import arange, sin, pi
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, FigureCanvasAgg
from matplotlib.figure import Figure
import matplotlib.backends.tkagg as tkagg
import tkinter as Tk

"""
Demonstrates one way of embedding Matplotlib figures into a PySimpleGUI window.

Basic steps are:
 * Create a Canvas Element
 * Layout form
 * Display form (NON BLOCKING)
 * Draw plots onto convas
 * Display form (BLOCKING)
"""


def draw_figure(canvas, figure, loc=(0, 0)):
    """ Draw a matplotlib figure onto a Tk canvas

    loc: location of top-left corner of figure on canvas in pixels.

    Inspired by matplotlib source: lib/matplotlib/backends/backend_tkagg.py
    """
    figure_canvas_agg = FigureCanvasAgg(figure)
    figure_canvas_agg.draw()
    figure_x, figure_y, figure_w, figure_h = figure.bbox.bounds
    figure_w, figure_h = int(figure_w), int(figure_h)
    photo = Tk.PhotoImage(master=canvas, width=figure_w, height=figure_h)

    # Position: convert from top-left anchor to center anchor
    canvas.create_image(loc[0] + figure_w/2, loc[1] + figure_h/2, image=photo)

    # Unfortunately, there's no accessor for the pointer to the native renderer
    tkagg.blit(photo, figure_canvas_agg.get_renderer()._renderer, colormode=2)

    # Return a handle which contains a reference to the photo object
    # which must be kept live or else the picture disappears
    return photo

f = Figure(figsize=(5, 4), dpi=100)
a = f.add_subplot(111)
t = arange(0.0, 3.0, 0.01)
s = sin(2*pi*t)

a.plot(t, s)
a.set_title('Tk embedding')
a.set_xlabel('X axis label')
a.set_ylabel('Y label')

# -------------------------------- GUI Starts Here --------------------------------
canvas_elem = g.Canvas(size=(500, 400))         # get the canvas we'll be drawing on
# define the form layout
layout = [[g.Text('Plot test')],
          [canvas_elem],
          [g.OK(pad=((250,0), 3))]]

# create the form and show it without the plot
form = g.FlexForm('Demo Application - Embedding Matplotlib In PySimpleGUI')
form.Layout(layout)
form.ReadNonBlocking()

# add the plot to the window
fig_photo = draw_figure(canvas_elem.TKCanvas, f)

# show it all again and get buttons
button, values = form.Read()