When I have multiple lines of text, how should the line height be calculated?

[jmu201621143028]

Thank you for your great work.
i have a question. When I have multiple lines of text, how should the line height be calculated?

This is how I calculate it now. ref

line_height = extents.ascender - extents.descender + extents.line_gap
cursor_x, cursor_y = -300, 0
texts = 'i love you\n我爱你\n愛してます'

"""
some code
"""

for pos, c in zip(positions, texts):
    if c == "\n":
        cursor_x = -300
        cursor_y += line_height * scale
        continue
    outline = get_glyph_outline(font_path, c)
    draw_outline_with_turtle(outline, scale=scale,
                             offset=(cursor_x + pos.x_offset * scale, cursor_y + pos.y_offset * scale))
    cursor_x += pos.x_advance * scale
    cursor_y += pos.y_advance * scale

Is there any better way to calculate line_height？