How to use the cairosvg.surface.cairo function in CairoSVG

def text(surface, node, draw_as_text=False):
    """Draw a text ``node``."""
    font_family = (
        (node.get('font-family') or 'sans-serif').split(',')[0].strip('"\' '))
    font_style = getattr(
        cairo, ('font_slant_{}'.format(node.get('font-style')).upper()),
        cairo.FONT_SLANT_NORMAL)
    font_weight = getattr(
        cairo, ('font_weight_{}'.format(node.get('font-weight')).upper()),
        cairo.FONT_WEIGHT_NORMAL)
    surface.context.select_font_face(font_family, font_style, font_weight)
    surface.context.set_font_size(surface.font_size)
    ascent, descent, _, max_x_advance, max_y_advance = (
        surface.context.font_extents())

    text_path_href = parse_url(node.get_href() or node.parent.get_href() or '')
    if text_path_href.fragment:
        text_path = surface.paths.get(text_path_href.fragment)
    else:
        text_path = None
    letter_spacing = size(surface, node.get('letter-spacing'))
    x_bearing, y_bearing, width, height = (
        surface.context.text_extents(node.text)[:4])

def point_following_path(path, width):
    """Get the point at ``width`` distance on ``path``."""
    total_length = 0
    for item in path:
        if item[0] == cairo.PATH_MOVE_TO:
            old_point = item[1]
        elif item[0] == cairo.PATH_LINE_TO:
            new_point = item[1]
            length = distance(
                old_point[0], old_point[1], new_point[0], new_point[1])
            total_length += length
            if total_length < width:
                old_point = new_point
            else:
                length -= total_length - width
                angle = point_angle(
                    old_point[0], old_point[1], new_point[0], new_point[1])
                x = cos(angle) * length + old_point[0]
                y = sin(angle) * length + old_point[1]
                return x, y

def point_following_path(path, width):
    """Get the point at ``width`` distance on ``path``."""
    total_length = 0
    for item in path:
        if item[0] == cairo.PATH_MOVE_TO:
            old_point = item[1]
        elif item[0] == cairo.PATH_LINE_TO:
            new_point = item[1]
            length = distance(
                old_point[0], old_point[1], new_point[0], new_point[1])
            total_length += length
            if total_length < width:
                old_point = new_point
            else:
                length -= total_length - width
                angle = point_angle(
                    old_point[0], old_point[1], new_point[0], new_point[1])
                x = cos(angle) * length + old_point[0]
                y = sin(angle) * length + old_point[1]
                return x, y

surface.context.scale(scale_x * tree_scale_x, scale_y * tree_scale_y)
        surface.context.translate(translate_x, translate_y)
        surface.draw(tree)
        surface.context.restore()
        return
    else:
        png_file = BytesIO()
        image = Image.open(BytesIO(image_bytes))

        if surface.map_image:
            image = surface.map_image(image)

        image.save(png_file, 'PNG')
        png_file.seek(0)

    image_surface = cairo.ImageSurface.create_from_png(png_file)
    image_surface.pattern = cairo.SurfacePattern(image_surface)
    image_surface.pattern.set_filter(IMAGE_RENDERING.get(
        node.get('image-rendering'), cairo.FILTER_GOOD))

    node.image_width = image_surface.get_width()
    node.image_height = image_surface.get_height()
    scale_x, scale_y, translate_x, translate_y = preserve_ratio(
        surface, node)

    # Clip image region (if necessary)
    if not (translate_x == 0 and
            translate_y == 0 and
            width == scale_x * node.image_width and
            height == scale_y * node.image_height):
        surface.context.rectangle(x, y, width, height)
        surface.context.clip()

def path_length(path):
    """Get the length of ``path``."""
    total_length = 0
    for item in path:
        if item[0] == cairo.PATH_MOVE_TO:
            old_point = item[1]
        elif item[0] == cairo.PATH_LINE_TO:
            new_point = item[1]
            length = distance(
                old_point[0], old_point[1], new_point[0], new_point[1])
            total_length += length
            old_point = new_point
    return total_length

"""

from .bounding_box import calculate_bounding_box, is_non_empty_bounding_box
from .features import match_features
from .helpers import paint, size, transform
from .parser import Tree
from .shapes import rect
from .surface import cairo
from .url import parse_url

BLEND_OPERATORS = {
    'darken': cairo.OPERATOR_DARKEN,
    'lighten': cairo.OPERATOR_LIGHTEN,
    'multiply': cairo.OPERATOR_MULTIPLY,
    'normal': cairo.OPERATOR_OVER,
    'screen': cairo.OPERATOR_SCREEN,
}

EXTEND_OPERATORS = {
    'none': cairo.EXTEND_NONE,
    'pad': cairo.EXTEND_PAD,
    'reflect': cairo.EXTEND_REFLECT,
    'repeat': cairo.EXTEND_REPEAT,
}


def update_def_href(surface, def_name, def_dict):
    """Update the attributes of the def according to its href attribute."""
    def_node = def_dict[def_name]
    href = parse_url(def_node.get_href()).fragment
    if href in def_dict:
        update_def_href(surface, href, def_dict)

Images manager.

"""

import os.path
from io import BytesIO

from PIL import Image, ImageOps

from .helpers import node_format, preserve_ratio, size
from .parser import Tree
from .surface import cairo
from .url import parse_url

IMAGE_RENDERING = {
    'optimizeQuality': cairo.FILTER_BEST,
    'optimizeSpeed': cairo.FILTER_FAST,
}


def image(surface, node):
    """Draw an image ``node``."""
    base_url = node.get('{http://www.w3.org/XML/1998/namespace}base')
    if not base_url and node.url:
        base_url = os.path.dirname(node.url) + '/'
    url = parse_url(node.get_href(), base_url)
    image_bytes = node.fetch_url(url, 'image/*')

    if len(image_bytes) < 5:
        return

    x, y = size(surface, node.get('x'), 'x'), size(surface, node.get('y'), 'y')

surface.context.translate(x, y)
        surface.set_context_size(
            *node_format(surface, tree, reference=False), scale=1,
            preserved_ratio=preserved_ratio(tree))
        surface.context.translate(*surface.context.get_current_point())
        surface.context.scale(scale_x, scale_y)
        surface.context.translate(translate_x, translate_y)
        surface.draw(tree)
        surface.context.restore()
        return
    else:
        png_file = BytesIO()
        Image.open(BytesIO(image_bytes)).save(png_file, 'PNG')
        png_file.seek(0)

    image_surface = cairo.ImageSurface.create_from_png(png_file)

    ### DSB
    ## Added:
    image_surface.pattern = cairo.SurfacePattern(image_surface)
    image_surface.pattern.set_filter(cairo.FILTER_NEAREST)
    ### DSB

    node.image_width = image_surface.get_width()
    node.image_height = image_surface.get_height()
    scale_x, scale_y, translate_x, translate_y = preserve_ratio(
        surface, node)

    # Clip image region (if necessary)
    if not (translate_x == 0 and
            translate_y == 0 and
            width == scale_x * node.image_width and