579 lines
20 KiB
Python
579 lines
20 KiB
Python
"""
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Cairo surface creators.
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"""
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import copy
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import io
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import cairocffi as cairo
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from .colors import color, negate_color
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from .defs import (
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apply_filter_after_painting, apply_filter_before_painting, clip_path,
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filter_, gradient_or_pattern, linear_gradient, marker, mask, paint_mask,
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parse_all_defs, pattern, prepare_filter, radial_gradient, use)
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from .helpers import (
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UNITS, PointError, clip_rect, node_format, normalize, paint,
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preserve_ratio, size, transform)
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from .image import image, invert_image
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from .parser import Tree
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from .path import draw_markers, path
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from .shapes import circle, ellipse, line, polygon, polyline, rect
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from .svg import svg
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from .text import text
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from .url import parse_url
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SHAPE_ANTIALIAS = {
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'optimizeSpeed': cairo.ANTIALIAS_FAST,
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'crispEdges': cairo.ANTIALIAS_NONE,
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'geometricPrecision': cairo.ANTIALIAS_BEST,
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}
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TEXT_ANTIALIAS = {
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'crispEdges': cairo.ANTIALIAS_NONE,
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'optimizeSpeed': cairo.ANTIALIAS_FAST,
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'optimizeLegibility': cairo.ANTIALIAS_GOOD,
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'geometricPrecision': cairo.ANTIALIAS_BEST,
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}
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TEXT_HINT_STYLE = {
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'geometricPrecision': cairo.HINT_STYLE_NONE,
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'optimizeLegibility': cairo.HINT_STYLE_FULL,
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}
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TEXT_HINT_METRICS = {
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'geometricPrecision': cairo.HINT_METRICS_OFF,
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'optimizeLegibility': cairo.HINT_METRICS_ON,
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}
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TAGS = {
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'a': text,
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'circle': circle,
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'clipPath': clip_path,
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'ellipse': ellipse,
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'filter': filter_,
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'image': image,
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'line': line,
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'linearGradient': linear_gradient,
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'marker': marker,
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'mask': mask,
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'path': path,
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'pattern': pattern,
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'polyline': polyline,
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'polygon': polygon,
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'radialGradient': radial_gradient,
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'rect': rect,
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'svg': svg,
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'text': text,
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'textPath': text,
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'tspan': text,
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'use': use,
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}
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PATH_TAGS = frozenset((
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'circle', 'ellipse', 'line', 'path', 'polygon', 'polyline', 'rect'))
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INVISIBLE_TAGS = frozenset((
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'clipPath', 'filter', 'linearGradient', 'marker', 'mask', 'pattern',
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'radialGradient', 'symbol'))
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class Surface(object):
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"""Abstract base class for CairoSVG surfaces.
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The ``width`` and ``height`` attributes are in device units (pixels for
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PNG, else points).
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The ``context_width`` and ``context_height`` attributes are in user units
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(i.e. in pixels), they represent the size of the active viewport.
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"""
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# Subclasses must either define this or override _create_surface()
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surface_class = None
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@classmethod
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def convert(cls, bytestring=None, *, file_obj=None, url=None, dpi=96,
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parent_width=None, parent_height=None, scale=1, unsafe=False,
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background_color=None, negate_colors=False,
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invert_images=False, write_to=None, output_width=None,
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output_height=None, **kwargs):
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"""Convert an SVG document to the format for this class.
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Specify the input by passing one of these:
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:param bytestring: The SVG source as a byte-string.
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:param file_obj: A file-like object.
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:param url: A filename.
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Give some options:
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:param dpi: The ratio between 1 inch and 1 pixel.
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:param parent_width: The width of the parent container in pixels.
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:param parent_height: The height of the parent container in pixels.
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:param scale: The ouptut scaling factor.
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:param unsafe: A boolean allowing external file access, XML entities
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and very large files
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(WARNING: vulnerable to XXE attacks and various DoS).
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Specifiy the output with:
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:param write_to: The filename of file-like object where to write the
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output. If None or not provided, return a byte string.
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Only ``bytestring`` can be passed as a positional argument, other
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parameters are keyword-only.
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"""
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tree = Tree(
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bytestring=bytestring, file_obj=file_obj, url=url, unsafe=unsafe,
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**kwargs)
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output = write_to or io.BytesIO()
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instance = cls(
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tree, output, dpi, None, parent_width, parent_height, scale,
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output_width, output_height, background_color,
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map_rgba=negate_color if negate_colors else None,
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map_image=invert_image if invert_images else None)
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instance.finish()
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if write_to is None:
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return output.getvalue()
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def __init__(self, tree, output, dpi, parent_surface=None,
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parent_width=None, parent_height=None,
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scale=1, output_width=None, output_height=None,
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background_color=None, map_rgba=None, map_image=None):
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"""Create the surface from a filename or a file-like object.
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The rendered content is written to ``output`` which can be a filename,
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a file-like object, ``None`` (render in memory but do not write
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anything) or the built-in ``bytes`` as a marker.
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Call the ``.finish()`` method to make sure that the output is
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actually written.
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"""
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self.cairo = None
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self.context_width, self.context_height = parent_width, parent_height
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self.cursor_position = [0, 0]
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self.cursor_d_position = [0, 0]
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self.text_path_width = 0
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self.tree_cache = {(tree.url, tree.get('id')): tree}
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if parent_surface:
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self.markers = parent_surface.markers
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self.gradients = parent_surface.gradients
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self.patterns = parent_surface.patterns
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self.masks = parent_surface.masks
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self.paths = parent_surface.paths
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self.filters = parent_surface.filters
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self.images = parent_surface.images
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else:
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self.markers = {}
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self.gradients = {}
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self.patterns = {}
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self.masks = {}
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self.paths = {}
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self.filters = {}
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self.images = {}
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self._old_parent_node = self.parent_node = None
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self.output = output
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self.dpi = dpi
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self.font_size = size(self, '12pt')
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self.stroke_and_fill = True
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width, height, viewbox = node_format(self, tree)
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if viewbox is None:
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viewbox = (0, 0, width, height)
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if output_width and output_height:
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width, height = output_width, output_height
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elif output_width:
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if width:
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# Keep the aspect ratio
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height *= output_width / width
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width = output_width
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elif output_height:
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if height:
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# Keep the aspect ratio
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width *= output_height / height
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height = output_height
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else:
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width *= scale
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height *= scale
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# Actual surface dimensions: may be rounded on raster surfaces types
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self.cairo, self.width, self.height = self._create_surface(
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width * self.device_units_per_user_units,
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height * self.device_units_per_user_units)
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if 0 in (self.width, self.height):
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raise ValueError('The SVG size is undefined')
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self.context = cairo.Context(self.cairo)
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# We must scale the context as the surface size is using physical units
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self.context.scale(
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self.device_units_per_user_units, self.device_units_per_user_units)
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# Initial, non-rounded dimensions
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self.set_context_size(width, height, viewbox, tree)
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self.context.move_to(0, 0)
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if background_color:
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self.context.set_source_rgba(*color(background_color))
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self.context.paint()
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self.map_rgba = map_rgba
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self.map_image = map_image
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self.draw(tree)
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@property
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def points_per_pixel(self):
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"""Surface resolution."""
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return 1 / (self.dpi * UNITS['pt'])
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@property
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def device_units_per_user_units(self):
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"""Ratio between Cairo device units and user units.
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Device units are pixels for PNG and SVG, and points for everything
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else. User units are pixels.
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"""
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return self.points_per_pixel
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def _create_surface(self, width, height):
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"""Create and return ``(cairo_surface, width, height)``."""
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cairo_surface = self.surface_class(self.output, width, height)
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return cairo_surface, width, height
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def set_context_size(self, width, height, viewbox, tree):
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"""Set the Cairo context size, set the SVG viewport size."""
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if viewbox:
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rect_x, rect_y = viewbox[0:2]
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tree.image_width = viewbox[2]
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tree.image_height = viewbox[3]
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else:
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rect_x, rect_y = 0, 0
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tree.image_width = width
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tree.image_height = height
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scale_x, scale_y, translate_x, translate_y = preserve_ratio(
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self, tree, width, height)
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rect_x, rect_y = rect_x * scale_x, rect_y * scale_y
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rect_width, rect_height = width, height
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self.context.translate(*self.context.get_current_point())
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self.context.translate(-rect_x, -rect_y)
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if tree.get('overflow', 'hidden') != 'visible':
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self.context.rectangle(rect_x, rect_y, rect_width, rect_height)
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self.context.clip()
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self.context.scale(scale_x, scale_y)
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self.context.translate(translate_x, translate_y)
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self.context_width = rect_width / scale_x
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self.context_height = rect_height / scale_y
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def finish(self):
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"""Read the surface content."""
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self.cairo.finish()
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def map_color(self, string, opacity=1):
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"""Parse a color ``string`` and apply ``map_rgba`` function to it."""
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rgba = color(string, opacity)
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return self.map_rgba(rgba) if self.map_rgba else rgba
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def draw(self, node):
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"""Draw ``node`` and its children."""
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# Parse definitions first
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if node.tag == 'svg':
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parse_all_defs(self, node)
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# Do not draw defs
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if node.tag == 'defs':
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return
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# Do not draw elements with width or height of 0
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if (('width' in node and size(self, node['width']) == 0) or
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('height' in node and size(self, node['height']) == 0)):
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return
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# Save context and related attributes
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old_parent_node = self.parent_node
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old_font_size = self.font_size
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old_context_size = self.context_width, self.context_height
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self.parent_node = node
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if "font" in node:
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font = parse_font(node["font"])
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for att in font:
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if att not in node:
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node[att] = font[att]
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self.font_size = size(self, node.get('font-size', '12pt'))
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self.context.save()
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# Apply transformations
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transform(
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self, node.get('transform'),
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transform_origin=node.get('transform-origin'))
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# Find and prepare opacity, masks and filters
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mask = parse_url(node.get('mask')).fragment
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filter_ = parse_url(node.get('filter')).fragment
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opacity = float(node.get('opacity', 1))
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if filter_:
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prepare_filter(self, node, filter_)
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if filter_ or mask or (opacity < 1 and node.children):
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self.context.push_group()
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# Move to (node.x, node.y)
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self.context.move_to(
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size(self, node.get('x'), 'x'),
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size(self, node.get('y'), 'y'))
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# Set node's drawing informations if the ``node.tag`` method exists
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line_cap = node.get('stroke-linecap')
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if line_cap == 'square':
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self.context.set_line_cap(cairo.LINE_CAP_SQUARE)
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if line_cap == 'round':
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self.context.set_line_cap(cairo.LINE_CAP_ROUND)
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join_cap = node.get('stroke-linejoin')
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if join_cap == 'round':
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self.context.set_line_join(cairo.LINE_JOIN_ROUND)
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if join_cap == 'bevel':
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self.context.set_line_join(cairo.LINE_JOIN_BEVEL)
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dash_array = normalize(node.get('stroke-dasharray', '')).split()
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if dash_array:
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dashes = [size(self, dash) for dash in dash_array]
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if sum(dashes):
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offset = size(self, node.get('stroke-dashoffset'))
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self.context.set_dash(dashes, offset)
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miter_limit = float(node.get('stroke-miterlimit', 4))
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self.context.set_miter_limit(miter_limit)
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# Clip
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rect_values = clip_rect(node.get('clip'))
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if len(rect_values) == 4:
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top = size(self, rect_values[0], 'y')
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right = size(self, rect_values[1], 'x')
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bottom = size(self, rect_values[2], 'y')
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left = size(self, rect_values[3], 'x')
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x = size(self, node.get('x'), 'x')
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y = size(self, node.get('y'), 'y')
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width = size(self, node.get('width'), 'x')
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height = size(self, node.get('height'), 'y')
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self.context.save()
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self.context.translate(x, y)
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self.context.rectangle(
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left, top, width - left - right, height - top - bottom)
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self.context.restore()
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self.context.clip()
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clip_path = parse_url(node.get('clip-path')).fragment
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if clip_path:
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path = self.paths.get(clip_path)
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if path:
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self.context.save()
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if path.get('clipPathUnits') == 'objectBoundingBox':
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x = size(self, node.get('x'), 'x')
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y = size(self, node.get('y'), 'y')
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width = size(self, node.get('width'), 'x')
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height = size(self, node.get('height'), 'y')
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self.context.translate(x, y)
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self.context.scale(width, height)
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path.tag = 'g'
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self.stroke_and_fill = False
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self.draw(path)
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self.stroke_and_fill = True
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path.tag = 'clipPath'
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self.context.restore()
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# TODO: fill rules are not handled by cairo for clips
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# if node.get('clip-rule') == 'evenodd':
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# self.context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
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self.context.clip()
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self.context.set_fill_rule(cairo.FILL_RULE_WINDING)
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save_cursor = copy.deepcopy(
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(self.cursor_position, self.cursor_d_position,
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self.text_path_width))
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# Only draw known tags
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if node.tag in TAGS:
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try:
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TAGS[node.tag](self, node)
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except PointError:
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# Error in point parsing, do nothing
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pass
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# Get stroke and fill opacity
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stroke_opacity = float(node.get('stroke-opacity', 1))
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fill_opacity = float(node.get('fill-opacity', 1))
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if opacity < 1 and not node.children:
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stroke_opacity *= opacity
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fill_opacity *= opacity
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# Manage display and visibility
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display = node.get('display', 'inline') != 'none'
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visible = display and (node.get('visibility', 'visible') != 'hidden')
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# Set font rendering properties
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self.context.set_antialias(SHAPE_ANTIALIAS.get(
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node.get('shape-rendering'), cairo.ANTIALIAS_DEFAULT))
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font_options = self.context.get_font_options()
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font_options.set_antialias(TEXT_ANTIALIAS.get(
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node.get('text-rendering'), cairo.ANTIALIAS_DEFAULT))
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font_options.set_hint_style(TEXT_HINT_STYLE.get(
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node.get('text-rendering'), cairo.HINT_STYLE_DEFAULT))
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font_options.set_hint_metrics(TEXT_HINT_METRICS.get(
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node.get('text-rendering'), cairo.HINT_METRICS_DEFAULT))
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self.context.set_font_options(font_options)
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# Fill and stroke
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if self.stroke_and_fill and visible and node.tag in TAGS:
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# Fill
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self.context.save()
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paint_source, paint_color = paint(node.get('fill', 'black'))
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if node.get('fill-rule') == 'evenodd':
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self.context.set_fill_rule(cairo.FILL_RULE_EVEN_ODD)
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if not gradient_or_pattern(self, node, paint_source, fill_opacity):
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self.context.set_source_rgba(
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*self.map_color(paint_color, fill_opacity))
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if TAGS[node.tag] == text:
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self.cursor_position = save_cursor[0]
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self.cursor_d_position = save_cursor[1]
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self.text_path_width = save_cursor[2]
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text(self, node, draw_as_text=True)
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else:
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self.context.fill_preserve()
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self.context.restore()
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# Stroke
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self.context.save()
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self.context.set_line_width(
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size(self, node.get('stroke-width', '1')))
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paint_source, paint_color = paint(node.get('stroke'))
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if not gradient_or_pattern(
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self, node, paint_source, stroke_opacity):
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self.context.set_source_rgba(
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*self.map_color(paint_color, stroke_opacity))
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self.context.stroke()
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self.context.restore()
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elif not visible:
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self.context.new_path()
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# Draw path markers
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draw_markers(self, node)
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# Draw children
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if display and node.tag not in INVISIBLE_TAGS:
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for child in node.children:
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self.draw(child)
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# Apply filter, mask and opacity
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if filter_ or mask or (opacity < 1 and node.children):
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self.context.pop_group_to_source()
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if filter_:
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apply_filter_before_painting(self, node, filter_)
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if mask in self.masks:
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paint_mask(self, node, mask, opacity)
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else:
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self.context.paint_with_alpha(opacity)
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if filter_:
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apply_filter_after_painting(self, node, filter_)
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# Clean cursor's position after 'text' tags
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if node.tag == 'text':
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self.cursor_position = [0, 0]
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self.cursor_d_position = [0, 0]
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self.text_path_width = 0
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|
|
|
self.context.restore()
|
|
self.parent_node = old_parent_node
|
|
self.font_size = old_font_size
|
|
self.context_width, self.context_height = old_context_size
|
|
|
|
|
|
class PDFSurface(Surface):
|
|
"""A surface that writes in PDF format."""
|
|
surface_class = cairo.PDFSurface
|
|
|
|
|
|
class PSSurface(Surface):
|
|
"""A surface that writes in PostScript format."""
|
|
surface_class = cairo.PSSurface
|
|
|
|
|
|
class EPSSurface(Surface):
|
|
"""A surface that writes in Encapsulated PostScript format."""
|
|
|
|
def _create_surface(self, width, height):
|
|
"""Create and return ``(cairo_surface, width, height)``."""
|
|
cairo_surface = cairo.PSSurface(self.output, width, height)
|
|
cairo_surface.set_eps(True)
|
|
return cairo_surface, width, height
|
|
|
|
|
|
class PNGSurface(Surface):
|
|
"""A surface that writes in PNG format."""
|
|
device_units_per_user_units = 1
|
|
|
|
def _create_surface(self, width, height):
|
|
"""Create and return ``(cairo_surface, width, height)``."""
|
|
width = int(round(width))
|
|
height = int(round(height))
|
|
cairo_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
|
|
return cairo_surface, width, height
|
|
|
|
def finish(self):
|
|
"""Read the PNG surface content."""
|
|
if self.output is not None:
|
|
self.cairo.write_to_png(self.output)
|
|
return super().finish()
|
|
|
|
|
|
class SVGSurface(Surface):
|
|
"""A surface that writes in SVG format.
|
|
|
|
It may seem pointless to render SVG to SVG, but this can be used
|
|
with ``output=None`` to get a vector-based single page cairo surface.
|
|
|
|
"""
|
|
device_units_per_user_units = 1
|
|
surface_class = cairo.SVGSurface
|
|
|
|
|
|
def parse_font(value):
|
|
ret = {"font-family": "", "font-size": "", "font-style": "normal",
|
|
"font-variant": "normal", "font-weight": "normal",
|
|
"line-height": "normal"}
|
|
|
|
font_styles = ["italic", "oblique"]
|
|
font_variants = ["small-caps"]
|
|
font_weights = ["bold", "bolder", "lighter", "100", "200", "300", "400",
|
|
"500", "600", "700", "800", "900"]
|
|
|
|
for element in value.split():
|
|
if element == "normal":
|
|
continue
|
|
elif ret["font-family"]:
|
|
ret["font-family"] += " " + element
|
|
elif element in font_styles:
|
|
ret["font-style"] = element
|
|
elif element in font_variants:
|
|
ret["font-variant"] = element
|
|
elif element in font_weights:
|
|
ret["font-weight"] = element
|
|
else:
|
|
if not ret["font-size"]:
|
|
parts = element.split("/")
|
|
ret["font-size"] = parts[0]
|
|
if len(parts) > 1:
|
|
ret["line-height"] = parts[1]
|
|
continue
|
|
else:
|
|
ret["font-family"] = element
|
|
|
|
return ret
|