Graphics / Hilbert

Use turtle graphics recursively to draw Hilbert curves.

from h2o_wave import ui, main, app, Q, graphics as g

def hilbert(t: g.Turtle, width: float, depth: int, reverse=False):  # recursive    angle = -90 if reverse else 90
    if depth == 0:        t.f(width).r(angle).f(width).r(angle).f(width)        return
    side = width * ((2 ** depth) - 1) / float((2 ** (depth + 1)) - 1)    edge = width - 2 * side
    t.r(angle)    hilbert(t, side, depth - 1, not reverse)    t.r(angle).f(edge)    hilbert(t, side, depth - 1, reverse)    t.l(angle).f(edge).l(angle)    hilbert(t, side, depth - 1, reverse)    t.f(edge).r(angle)    hilbert(t, side, depth - 1, not reverse)    t.r(angle)

def make_hilbert_curve(width: float, depth: int):    t = g.turtle().f(0).pd()    hilbert(t, width, depth)    return t.d()

@app('/demo')async def serve(q: Q):    hilbert_curve = make_hilbert_curve(300, q.args.depth or 5)
    if not q.client.initialized:        q.page['curve'] = ui.graphics_card(            box='1 1 4 6', view_box='0 0 300 300', width='100%', height='100%',            scene=g.scene(                hilbert_curve=g.path(d=hilbert_curve, fill='none', stroke='#333')            ),        )        q.page['form'] = ui.form_card(            box='1 7 4 1', items=[                ui.slider(name='depth', label='Play with this Hilbert curve!', min=1, max=6, value=5, trigger=True),            ],        )        q.client.initialized = True    else:        g.draw(q.page['curve'].scene.hilbert_curve, d=hilbert_curve)
    await q.page.save()

Tags:  graphics