#!python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2022/03/25 21:44:30 +0900>
"""
pycairo clipping sample.

* Windows10 x64 21H2 + Python 2.7.18 32bit + pycairo 1.8.10
* Windows10 x64 21H2 + Python 3.9.11 64bit + pycairo 1.21.0
"""

import cairo
import math


def draw_rounder_rectangle(ctx, x, y, w, h, ra):
    """Set sub path rounded rectangle."""
    deg = math.pi / 180.0
    ctx.new_sub_path()
    ctx.arc(x + w - ra, y + ra, ra, -90 * deg, 0 * deg)
    ctx.arc(x + w - ra, y + h - ra, ra, 0 * deg, 90 * deg)
    ctx.arc(x + ra, y + h - ra, ra, 90 * deg, 180 * deg)
    ctx.arc(x + ra, y + ra, ra, 180 * deg, 270 * deg)
    ctx.close_path()


def main():
    w, h = 256, 256

    # draw base surface
    base = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
    c = cairo.Context(base)

    # fill background
    c.set_source_rgb(0.5, 0.5, 0.5)
    c.rectangle(0, 0, w, h)
    c.fill()

    # draw lines
    c.set_source_rgb(0, 1.0, 0)
    c.set_line_width(6)
    for y in range(0, h, 32):
        c.move_to(0, y)
        c.line_to(w, y)
        c.stroke()

    ims = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
    c = cairo.Context(ims)
    c.set_source_surface(base, 0, 0)

    # set clipping path
    s = 16
    draw_rounder_rectangle(c, s, s, w - s * 2, h - s * 2, 32)

    # clipping
    c.clip()
    c.paint()

    # save surface as png image
    ims.write_to_png("01_clipping_result.png")


if __name__ == '__main__':
    main()