mirror of
https://github.com/Kozea/WeasyPrint.git
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137 lines
4.5 KiB
Python
137 lines
4.5 KiB
Python
# coding: utf8
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"""
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weasyprint.images
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-----------------
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Fetch and decode images in various formats.
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:copyright: Copyright 2011-2012 Simon Sapin and contributors, see AUTHORS.
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:license: BSD, see LICENSE for details.
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"""
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from __future__ import division, unicode_literals
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from io import BytesIO
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import cairocffi
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cairocffi.install_as_pycairo() # for CairoSVG
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import cairosvg.parser
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import cairosvg.surface
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assert cairosvg.surface.cairo is cairocffi, (
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'CairoSVG is using pycairo instead of cairocffi. '
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'Make sure it is not imported before WeasyPrint.')
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try:
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from cairocffi import pixbuf
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except OSError:
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pixbuf = None
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from .logger import LOGGER
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def gdkpixbuf_loader(file_obj, string):
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"""Load raster images with GDK-PixBuf."""
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if pixbuf is None:
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raise OSError(
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'Could not load GDK-Pixbuf. '
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'PNG and SVG are the only image formats available.')
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if string is None:
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string = file_obj.read()
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surface, format_name = pixbuf.decode_to_image_surface(string)
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if format_name == 'jpeg':
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surface.set_mime_data('image/jpeg', string)
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get_pattern = lambda: cairocffi.SurfacePattern(surface)
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return get_pattern, surface.get_width(), surface.get_height()
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def cairo_png_loader(file_obj, string):
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"""Return a cairo Surface from a PNG byte stream."""
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surface = cairocffi.ImageSurface.create_from_png(
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file_obj or BytesIO(string))
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get_pattern = lambda: cairocffi.SurfacePattern(surface)
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return get_pattern, surface.get_width(), surface.get_height()
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class ScaledSVGSurface(cairosvg.surface.SVGSurface):
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"""
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Have the cairo Surface object have intrinsic dimension
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in pixels instead of points.
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"""
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@property
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def device_units_per_user_units(self):
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scale = super(ScaledSVGSurface, self).device_units_per_user_units
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return scale / 0.75
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def cairosvg_loader(file_obj, string, uri):
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"""Return a cairo Surface from a SVG byte stream.
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This loader uses CairoSVG: http://cairosvg.org/
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"""
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if uri.startswith('data:'):
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# Don’t pass data URIs to CairoSVG.
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# They are useless for relative URIs anyway.
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uri = None
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if file_obj:
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string = file_obj.read()
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def get_surface():
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tree = cairosvg.parser.Tree(bytestring=string, url=uri)
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# Draw to a cairo surface but do not write to a file
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surface = ScaledSVGSurface(tree, output=None, dpi=96)
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return surface.cairo, surface.width, surface.height
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def get_pattern():
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# Do not re-use the Surface object, but regenerate it as needed.
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# If a surface for a SVG image is still alive by the time we call
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# show_page(), cairo will rasterize the image instead writing vectors.
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surface, _, _ = get_surface()
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return cairocffi.SurfacePattern(surface)
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# Render once to get the size and trigger any exception.
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# If this does not raise, future calls to get_pattern() will hopefully
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# not raise either.
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_, width, height = get_surface()
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if not (width > 0 and height > 0):
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raise ValueError('Images without an intrinsic size are not supported.')
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return get_pattern, width, height
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def get_image_from_uri(cache, url_fetcher, uri, type_=None):
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"""Get a cairo Pattern from an image URI."""
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try:
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missing = object()
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image = cache.get(uri, missing)
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if image is not missing:
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return image
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result = url_fetcher(uri)
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try:
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if not type_:
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type_ = result['mime_type'] # Use eg. the HTTP header
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#else: the type was forced by eg. a 'type' attribute on <embed>
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if type_ == 'image/svg+xml':
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image = cairosvg_loader(
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result.get('file_obj'), result.get('string'), uri)
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elif type_ == 'image/png':
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image = cairo_png_loader(
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result.get('file_obj'), result.get('string'))
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else:
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image = gdkpixbuf_loader(
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result.get('file_obj'), result.get('string'))
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finally:
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if 'file_obj' in result:
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try:
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result['file_obj'].close()
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except Exception: # pragma: no cover
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# May already be closed or something.
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# This is just cleanup anyway.
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pass
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except Exception as exc:
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LOGGER.warn('Error for image at %s : %r', uri, exc)
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image = None
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cache[uri] = image
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return image
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