eyes.py

from math import sqrt, cos, sin, pi, radians
from glc import Gif
from glc.color import Color
from glc.utils import draw_image
from cairo import ImageSurface

def intersection(x, y, rx, ry):
    px, py = 0, 0
    if x == 0:
        py = -ry if y < 0 else ry
    elif y == 0:
        px = -rx if x < 0 else rx
    elif x != 0 and y != 0:
        m = y / x
        n1 = ry / (rx * m)
        px = (ry / m) * sqrt(1 / (1 + n1 * n1))
        px = -px if y < 0 else px
        py = m * px
    return px, py

def oval(context, x, y, rx, ry, color):
    context.save()
    context.translate(x, y)
    context.scale(rx * 0.01, ry * 0.01)
    context.arc(0, 0, 100, 0, 2 * pi)
    context.set_source_rgba(*color)
    context.fill()
    context.restore()

def line(context, x0, y0, x1, y1, color, line_width=5):
    context.save()
    context.move_to(x0, y0)
    context.line_to(x1, y1)
    context.set_source_rgba(*color)
    context.set_line_width(line_width)
    context.stroke()
    context.restore()

with Gif('eyefunny.gif') as a:
    a.set_bg_color('0xff36393e').set_duration(6)
    w, h = a.w, a.h
    cx, cy = w * 0.5, h * 0.5
    l = a.render_list

    with open('../dev/72x72/1f528.png', 'rb') as f:
        emoji = ImageSurface.create_from_png(f)

    emojiw, emojih = emoji.get_width(), emoji.get_height()

    def before_render(render_list, surface, context, t):
        leadr = w * 0.3
        leadx, leady = cx + cos(2 * pi * t) + sin(4 * pi * t) * leadr, cy + sin(2 * pi * t) * leadr
        step = w // 10
        size = step * 0.5
        eyerx, eyery = size * 0.5, size * 0.6
        start_x, start_y = int(eyerx), int(eyery)
        stepx = step + int(start_x * 1.5)
        eye_sep = size * 0.6

        offsetx, offsety = 35, 10

        for i in range(start_x + offsetx, w - offsetx, stepx):
            for j in range(start_y + offsety, h - offsety, step):
                ax, ay = i - eye_sep, j
                bx, by = i + eye_sep, j

                air = size * 0.3

                aix, aiy = intersection(leadx - ax - air * 1.5, leady - ay, eyerx - air, eyery - air)

                oval(context, ax, ay, eyerx, eyery, Color('white'))
                oval(context, aix + ax, aiy + ay, air, air, Color('0x36393e'))

                bix, biy = intersection(leadx - bx + air * 1.5, leady - by, eyerx - air, eyery - air)

                oval(context, bx, by, eyerx, eyery, Color('white'))
                oval(context, bix + bx, biy + by, air, air, Color('0x36393e'))

                # line(context, bix + bx, biy + by, leadx, leady, Color('red'), 1)
                # line(context, aix + ax, aiy + ay, leadx, leady, Color('red'), 1)


        draw_image(context, emoji, leadx - emojiw * 0.5, leady - emojih * 0.5)

    l.before_render = before_render
    a.save()