bandsaunter/tests/test_themes.py

"""The colour themes, and the glow that goes with the vector ones.

A theme changes both drawings at once, because both read their colours out
of the same palette: the animation looks indices up in it directly and the
window asks it for a QColor.  So the tests here are mostly about that
palette -- that it is rewritten rather than replaced, that every theme keeps
the aerodromes distinguishable from the aircraft, and that the halo goes
where light would go and nowhere else.
"""
import numpy as np
import pytest

from bandsaunter import flightmap as fm
from bandsaunter import themes


@pytest.fixture(autouse=True)
def back_to_night():
    """Every test leaves the program drawing the way it found it."""
    yield
    fm.set_theme(themes.DEFAULT_THEME)


# ---------------------------------------------------------------------------
# Choosing one
# ---------------------------------------------------------------------------

def test_every_theme_says_what_it_is():
    for name, theme in themes.THEMES.items():
        assert theme.name == name
        assert theme.summary and not theme.summary.endswith(".")
        assert len(theme.stops) >= 2
        assert theme.stops[0][0] == 0.0


def test_a_theme_can_be_asked_for_by_name_or_by_what_it_looks_like():
    assert themes.theme_named("phosphor").name == "phosphor"
    assert themes.theme_named("green").name == "phosphor"
    assert themes.theme_named("wargames").name == "digital"
    assert themes.theme_named("BLUE").name == "digital"
    assert themes.theme_named("  amber  ").name == "amber"


def test_a_name_nobody_recognises_is_the_default_rather_than_a_refusal():
    """A theme is how the picture looks.  Refusing to draw an evening's
    flying because of a misspelt colour would be the wrong trade."""
    assert themes.theme_named("puce").name == themes.DEFAULT_THEME
    assert themes.theme_named("").name == themes.DEFAULT_THEME
    assert themes.theme_named(None).name == themes.DEFAULT_THEME


def test_no_two_themes_share_a_name_or_an_alias():
    seen = set()
    for theme in themes.THEMES.values():
        for word in (theme.name,) + tuple(theme.aliases):
            assert word not in seen, word
            seen.add(word)


# ---------------------------------------------------------------------------
# What setting one does to the palette
# ---------------------------------------------------------------------------

def test_the_palette_is_written_over_rather_than_replaced():
    """Both drawings and every one of their helpers hold a reference to
    this array.  A new one would leave half the program painting in the
    colours of the theme before."""
    before = fm.PALETTE
    fm.set_theme("phosphor")
    assert fm.PALETTE is before
    assert tuple(fm.PALETTE[fm.BG]) != (14, 16, 22)


def test_setting_a_theme_says_which_one_it_settled_on():
    assert fm.set_theme("norad").name == "digital"
    assert fm.set_theme("puce").name == themes.DEFAULT_THEME


def test_the_default_theme_draws_exactly_what_it_always_drew():
    """The colours this program has always used, unchanged: an existing
    recording redrawn today has to come out the same picture."""
    fm.set_theme("phosphor")
    fm.set_theme("night")
    assert tuple(fm.PALETTE[fm.BG]) == (14, 16, 22)
    assert tuple(fm.PALETTE[fm.INK]) == (196, 204, 218)
    assert tuple(fm.PALETTE[fm.RAMP]) == (252, 96, 72)
    assert tuple(fm.PALETTE[fm.RAMP + fm.RAMP_STEPS - 1]) == (158, 142, 255)


def _lab(rgb):
    c = np.asarray(rgb, float) / 255.0
    c = np.where(c > 0.04045, ((c + 0.055) / 1.055) ** 2.4, c / 12.92)
    m = np.array([[0.4124, 0.3576, 0.1805], [0.2126, 0.7152, 0.0722],
                  [0.0193, 0.1192, 0.9505]])
    xyz = (c @ m.T) / np.array([0.9505, 1.0, 1.089])
    f = np.where(xyz > 0.008856, np.cbrt(xyz), 7.787 * xyz + 16 / 116)
    return np.array([116 * f[1] - 16, 500 * (f[0] - f[1]), 200 * (f[1] - f[2])])


def test_no_theme_lets_an_aerodrome_be_mistaken_for_an_aircraft():
    """The whole reason the aerodromes stopped being amber.  Stated as the
    distance rather than as the colour, so that a new theme cannot quietly
    walk an aircraft back into the airports."""
    for name in themes.THEMES:
        fm.set_theme(name)
        airport = _lab(fm.PALETTE[fm.AIRPORT])
        apart = min(float(np.linalg.norm(airport - _lab(fm.PALETTE[fm.RAMP + i])))
                    for i in range(fm.RAMP_STEPS))
        assert apart > 40, f"{name}: only {apart:.0f} units apart"


def test_a_phosphor_theme_reads_height_as_brightness():
    """One colour to spend, so it cannot be spent on hue.  Low is dim and
    high burns, which is the constraint those screens actually had."""
    for name in ("digital", "phosphor", "amber", "red"):
        theme = fm.set_theme(name)
        assert theme.height_is_brightness
        weights = [int(fm.PALETTE[fm.RAMP + i].astype(int).sum())
                   for i in range(fm.RAMP_STEPS)]
        assert weights == sorted(weights), f"{name} is not monotonic"
        assert weights[-1] > weights[0] * 3


def test_the_default_theme_reads_height_as_hue_instead():
    fm.set_theme("night")
    assert not fm.THEME.height_is_brightness


def test_every_theme_fills_the_palette_without_running_off_the_end():
    for name in themes.THEMES:
        fm.set_theme(name)
        assert fm.PALETTE.shape == (256, 3)
        assert fm.GLOW + 6 <= 256
        # Nothing drawn with is left as the black the unused tail is.
        for index in (fm.INK, fm.AIRPORT, fm.RAMP, fm.GROUND + 31):
            assert fm.PALETTE[index].any(), (name, index)


# ---------------------------------------------------------------------------
# The glow
# ---------------------------------------------------------------------------

def _picture(width=80, height=60):
    return np.full((height, width), fm.BG, dtype=np.uint8)


def test_the_default_theme_has_no_glow_at_all():
    fm.set_theme("night")
    img = _picture()
    img[30, 10:70] = fm.RAMP + 20
    assert np.array_equal(fm.bloom(img), img)


def test_a_line_on_a_vector_theme_gets_a_halo_either_side_of_it():
    fm.set_theme("phosphor")
    img = _picture()
    img[30, 10:70] = fm.RAMP + 20
    out = fm.bloom(img)
    assert (out[30, 10:70] == fm.RAMP + 20).all(), "the core was painted over"
    assert (out[29, 10:70] == fm.TRAIL + 20).all(), "no halo above the line"
    assert (out[31, 10:70] == fm.TRAIL + 20).all(), "no halo below it"
    assert (out[28, 10:70] == fm.OLD + 20).all(), "no second, fainter ring"
    assert (out[27, 10:70] == fm.BG).all(), "the halo reaches too far"


def test_the_halo_is_the_colour_of_the_thing_that_cast_it():
    """A green aeroplane glows green and a red one red: the halo is the
    aircraft's own dimmed colour, which is what a phosphor would spread."""
    fm.set_theme("digital")
    for step in (0, 12, 31):
        img = _picture()
        img[30, 10:70] = fm.RAMP + step
        out = fm.bloom(img)
        assert (out[29, 10:70] == fm.TRAIL + step).all()


def test_a_halo_never_paints_over_something_else_that_was_drawn():
    """A halo is what light does to the dark around a line.  Painting it
    over another line would be light doing something light does not do."""
    fm.set_theme("phosphor")
    img = _picture()
    img[30, 10:70] = fm.RAMP + 20            # an aeroplane
    img[29, 10:70] = fm.AIRPORT              # an aerodrome right beside it
    out = fm.bloom(img)
    assert (out[29, 10:70] == fm.AIRPORT).all()


def test_the_halo_does_not_wrap_round_the_edge_of_the_picture():
    """Rolled and then cut: without the cut, a line down the left edge
    would glow on the right edge of the picture."""
    fm.set_theme("amber")
    img = _picture()
    img[:, 0] = fm.RAMP + 20
    out = fm.bloom(img)
    assert (out[:, 1] == fm.TRAIL + 20).all()
    assert (out[:, -1] == fm.BG).all()
    assert (out[:, -2] == fm.BG).all()

    tall = _picture()
    tall[0, :] = fm.AIRPORT
    assert (fm.bloom(tall)[-1, :] == fm.BG).all()


def test_the_halo_goes_over_the_map_and_the_grid_but_not_the_aircraft():
    fm.set_theme("digital")
    img = np.full((60, 80), fm.GROUND + 10, dtype=np.uint8)
    img[30, 40] = fm.INK
    out = fm.bloom(img)
    assert out[30, 41] != fm.GROUND + 10, "no halo over the map"
    assert out[30, 40] == fm.INK


def test_the_nearer_ring_wins_where_two_meet():
    """Which is what happens on the tube as well."""
    fm.set_theme("phosphor")
    img = _picture()
    img[30, 40] = fm.RAMP + 20
    out = fm.bloom(img)
    assert out[31, 40] == fm.TRAIL + 20      # near
    assert out[32, 40] == fm.OLD + 20        # far


# ---------------------------------------------------------------------------
# What else a vector theme changes
# ---------------------------------------------------------------------------

def test_a_phosphor_theme_names_the_country_instead_of_drawing_its_flag():
    """A flag is half a dozen colours and a phosphor screen has one.  Two
    letters are what a display of the period would have done anyway."""
    from bandsaunter.flags import FLAG_H, FLAG_W

    fm.set_theme("night")
    flagged = np.full((40, 60), fm.BG, dtype=np.uint8)
    fm.draw_flag(flagged, 5, 5, "US")
    patch = flagged[5:5 + FLAG_H, 5:5 + FLAG_W]
    assert ((patch >= fm.FLAG) & (patch < fm.FLAG + 12)).any()

    fm.set_theme("phosphor")
    lettered = np.full((40, 60), fm.BG, dtype=np.uint8)
    fm.draw_flag(lettered, 5, 5, "US")
    patch = lettered[5:5 + FLAG_H, 5:5 + FLAG_W]
    assert not ((patch >= fm.FLAG) & (patch < fm.FLAG + 12)).any()
    assert (lettered == fm.DIM).any(), "the letters were not drawn either"


def test_a_vector_theme_pushes_the_map_underneath_well_back():
    """A tinted photograph of a county behind the vectors is the one thing
    that stops a vector display looking like one."""
    levels = np.full((8, 8), fm.GROUND_SHADES - 1, dtype=np.uint8)
    fm.set_theme("night")
    plain = int(fm.dim_ground(levels, 0.7).max())
    fm.set_theme("digital")
    quiet = int(fm.dim_ground(levels, 0.7).max())
    assert quiet < plain * 0.6, f"{quiet} is not much darker than {plain}"


def test_the_brightness_setting_still_does_something_on_a_vector_theme():
    levels = np.full((8, 8), fm.GROUND_SHADES - 1, dtype=np.uint8)
    fm.set_theme("phosphor")
    assert int(fm.dim_ground(levels, 1.0).max()) > \
        int(fm.dim_ground(levels, 0.3).max())