How to use uharfbuzz - 10 common examples

buf.add_str(string)
        buf.guess_segment_properties()
        buf.direction = "TTB"

        def v_advance_func(font, gid, data):
            return 456

        def v_origin_func(font, gid, data):
            return (True, 345, 567)

        funcs = hb.FontFuncs.create()
        funcs.set_glyph_v_advance_func(v_advance_func, None)
        funcs.set_glyph_v_origin_func(v_origin_func, None)
        blankfont.funcs = funcs

        hb.shape(blankfont, buf)
        infos = [(pos.y_advance, pos.x_offset, pos.y_offset) for pos in buf.glyph_positions]
        assert infos == expected

string = "edcba"
        buf = hb.Buffer()
        buf.add_str(string)
        buf.guess_segment_properties()

        messages = []
        infos_trace = []
        positions_trace = []

        def message(msg):
            messages.append(msg)
            infos_trace.append(buf.glyph_infos)
            positions_trace.append(buf.glyph_positions)

        buf.set_message_func(message)
        hb.shape(blankfont, buf)
        gids = [g.codepoint for g in buf.glyph_infos]
        assert gids == [5, 4, 1, 2, 1]
        pos = [g.x_advance for g in buf.glyph_positions]
        assert pos == [0, 0, 0, 100, 0]
        expected_messages = [
            'start table GSUB',
            'start lookup 0',
            'end lookup 0',
            'end table GSUB',
            'start table GPOS',
            'start lookup 0',
            'end lookup 0',
            'end table GPOS',
        ]
        assert messages == expected_messages
        gids_trace = [[g.codepoint for g in infos] for infos in infos_trace]

def test_cluster_level(self):
        buf = hb.Buffer()

        assert buf.cluster_level == hb.BufferClusterLevel.DEFAULT

        buf.cluster_level = hb.BufferClusterLevel.MONOTONE_CHARACTERS
        assert buf.cluster_level == hb.BufferClusterLevel.MONOTONE_CHARACTERS

        buf.cluster_level = hb.BufferClusterLevel.MONOTONE_GRAPHEMES
        assert buf.cluster_level == hb.BufferClusterLevel.MONOTONE_GRAPHEMES

        buf.cluster_level = hb.BufferClusterLevel.CHARACTERS
        assert buf.cluster_level == hb.BufferClusterLevel.CHARACTERS

        buf.cluster_level = hb.BufferClusterLevel.DEFAULT
        assert buf.cluster_level == hb.BufferClusterLevel.DEFAULT

def test_glyh_name_no_features(self, blankfont, string, expected):
        buf = hb.Buffer()
        buf.add_str(string)
        buf.guess_segment_properties()
        hb.shape(blankfont, buf)
        # font.get_glyph_name() returns None if the font does not contain glyph names
        # or if the glyph ID does not exist.
        glyph_names = [blankfont.get_glyph_name(g.codepoint) for g in buf.glyph_infos]
        assert glyph_names == expected
        assert blankfont.get_glyph_name(1000) is None
        # font.glyph_to_string() return "gidN" if the font does not contain glyph names
        # or if the glyph ID does not exist.
        glyph_names = [blankfont.glyph_to_string(g.codepoint) for g in buf.glyph_infos]
        assert glyph_names == expected
        assert blankfont.glyph_to_string(1000) == 'gid1000'

def test_gid_and_cluster_no_features(self, blankfont, string, expected):
        buf = hb.Buffer()
        buf.add_str(string)
        buf.guess_segment_properties()
        hb.shape(blankfont, buf)
        infos = [(g.codepoint, g.cluster) for g in buf.glyph_infos]
        assert infos == expected

def test_add_utf8(self):
        buf = hb.Buffer()
        buf.add_utf8("aбç💩e".encode("utf-8"))
        infos = [(g.codepoint, g.cluster) for g in buf.glyph_infos]
        assert infos == [(0x61, 0), (0x431, 1), (0xE7, 3), (0x1F4A9, 5), (0x65, 9)]

def test_message_func_crash(self, blankfont):
        string = "edcba"
        buf = hb.Buffer()
        buf.add_str(string)
        buf.guess_segment_properties()
        message_collector = MessageCollector()
        buf.set_message_func(message_collector.message)
        hb.shape(blankfont, buf)

def opensans():
    """Return a subset of OpenSans.ttf containing the following glyphs/characters:
    [
        {gid=0, name=".notdef"},
        {gid=1, name="A", code=0x41},
    ]
    """
    face = hb.Face(OPEN_SANS_TTF_PATH.read_bytes())
    font = hb.Font(face)
    upem = face.upem
    font.scale = (upem, upem)
    hb.ot_font_set_funcs(font)
    return font

def test_create(self):
        buf = hb.Buffer.create()

def blankfont():
    """Return a subset of AdobeBlank.ttf containing the following glyphs/characters:
    [
        {gid=0, name=".notdef"},
        {gid=1, name="a", code=0x61},
        {gid=2, name="b", code=0x62},
        {gid=3, name="c", code=0x63},
        {gid=4, name="d", code=0x64},
        {gid=5, name="e", code=0x65},
        {gid=6, name="ccedilla", code=0x62},
        {gid=7, name="uni0431", code=0x0431},  # CYRILLIC SMALL LETTER BE
        {gid=8, name="u1F4A9", code=0x1F4A9},  # PILE OF POO
    ]
    """
    face = hb.Face(ADOBE_BLANK_TTF_PATH.read_bytes())
    font = hb.Font(face)
    upem = face.upem
    font.scale = (upem, upem)
    hb.ot_font_set_funcs(font)
    return font