#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/03/22 21:58:42 +0900>
"""
pycairo in tkinter.

python - Cairo with tkinter? - Stack Overflow
https://stackoverflow.com/questions/25480853/cairo-with-tkinter

* Windows10 x64 21H2 + Python 2.7.18 32bit + Pillow 6.2.2 + pycairo 1.8.10
* Windows10 x64 21H2 + Python 3.9.11 64bit + Pillow 9.0.1 + pycairo 1.21.0

"""

import sys

if sys.version_info.major == 2:
    # Python 2.7
    import Tkinter as tk
else:
    # Python 3.x
    import tkinter as tk

from PIL import Image
from PIL import ImageTk
import cairo


def conv_surface_to_photo(surface):
    """Convert pycairo surface to Tk PhotoImage."""
    w, h = surface.get_width(), surface.get_height()
    m = surface.get_data()

    if sys.version_info.major == 2:
        # Python 2.7
        im = Image.frombuffer("RGBA", (w, h), m, "raw", "BGRA", 0, 1)
    else:
        # Python 3.x
        im = Image.frombuffer("RGBA", (w, h), m, "raw", "RGBA", 0, 1)

        # BGRA -> RGBA
        r, g, b, a = im.split()
        im = Image.merge("RGBA", (b, g, r, a))

        # data = im.tobytes("raw", "BGRA", 0, 1)
        # im = Image.frombytes("RGBA", (w, h), data)

    return ImageTk.PhotoImage(im)


def main():
    print(sys.version)
    
    w, h = 640, 480
    root = tk.Tk()
    # root.geometry("{}x{}".format(w, h))

    root.surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
    w = root.surface.get_width()
    h = root.surface.get_height()

    # draw something with pycairo
    ctx = cairo.Context(root.surface)

    ctx.scale(w, h)

    ctx.rectangle(0, 0, 0.5, 0.5)
    ctx.set_source_rgba(1, 0, 0, 0.8)
    ctx.fill()

    ctx.rectangle(0.5, 0, 0.5, 0.5)
    ctx.set_source_rgba(0, 1, 0, 0.8)
    ctx.fill()

    ctx.rectangle(0, 0.5, 0.5, 0.5)
    ctx.set_source_rgba(0, 0, 1, 0.8)
    ctx.fill()

    # convert cairo image surface to tk.PhotoImage
    root._image_ref = conv_surface_to_photo(root.surface)

    label = tk.Label(root, image=root._image_ref)
    label.pack(expand=True, fill="both")

    root.mainloop()


if __name__ == "__main__":
    main()