mirror of
https://github.com/Kozea/WeasyPrint.git
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451 lines
17 KiB
Python
451 lines
17 KiB
Python
# coding: utf8
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"""
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weasyprint.document
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-------------------
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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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import io
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import sys
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import math
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import shutil
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import functools
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import cairo
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from . import CSS
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from . import images
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from .logger import LOGGER
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from .css import get_all_computed_styles
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from .formatting_structure import boxes
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from .formatting_structure.build import build_formatting_structure
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from .layout import layout_document
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from .draw import draw_page, stacked, percentage
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from .pdf import write_pdf_metadata
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from .compat import izip, iteritems
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from .urls import FILESYSTEM_ENCODING
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def _get_matrix(box):
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"""Return the matrix for the CSS transforms on this box.
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:returns: a :class:`cairo.Matrix` object or :obj:`None`.
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"""
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# "Transforms apply to block-level and atomic inline-level elements,
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# but do not apply to elements which may be split into
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# multiple inline-level boxes."
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# http://www.w3.org/TR/css3-2d-transforms/#introduction
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if box.style.transform and not isinstance(box, boxes.InlineBox):
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border_width = box.border_width()
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border_height = box.border_height()
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origin_x, origin_y = box.style.transform_origin
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origin_x = box.border_box_x() + percentage(origin_x, border_width)
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origin_y = box.border_box_y() + percentage(origin_y, border_height)
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matrix = cairo.Matrix()
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matrix.translate(origin_x, origin_y)
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for name, args in box.style.transform:
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if name == 'scale':
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matrix.scale(*args)
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elif name == 'rotate':
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matrix.rotate(args)
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elif name == 'translate':
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translate_x, translate_y = args
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matrix.translate(
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percentage(translate_x, border_width),
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percentage(translate_y, border_height),
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)
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else:
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if name == 'skewx':
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args = (1, 0, math.tan(args), 1, 0, 0)
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elif name == 'skewy':
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args = (1, math.tan(args), 0, 1, 0, 0)
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else:
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assert name == 'matrix'
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matrix = cairo.Matrix(*args) * matrix
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matrix.translate(-origin_x, -origin_y)
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box.transformation_matrix = matrix
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return matrix
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def rectangle_aabb(matrix, pos_x, pos_y, width, height):
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"""Apply a transformation matrix to an axis-aligned rectangle
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and return its axis-aligned bounding box as ``(x, y, width, height)``
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"""
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transform_point = matrix.transform_point
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x1, y1 = transform_point(pos_x, pos_y)
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x2, y2 = transform_point(pos_x + width, pos_y)
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x3, y3 = transform_point(pos_x, pos_y + height)
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x4, y4 = transform_point(pos_x + width, pos_y + height)
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box_x1 = min(x1, x2, x3, x4)
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box_y1 = min(y1, y2, y3, y4)
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box_x2 = max(x1, x2, x3, x4)
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box_y2 = max(y1, y2, y3, y4)
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return box_x1, box_y1, box_x2 - box_x1, box_y2 - box_y1
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class _TaggedTuple(tuple):
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"""A tuple with a :attr:`sourceline` attribute,
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The line number in the HTML source for whatever the tuple represents.
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"""
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def _get_metadata(box, bookmarks, links, anchors, matrix):
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bookmark_label = box.bookmark_label
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bookmark_level = box.bookmark_level
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link = box.style.link
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anchor_name = box.style.anchor
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has_bookmark = bookmark_label and bookmark_level
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# 'link' is inherited but redundant on text boxes
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has_link = link and not isinstance(box, boxes.TextBox)
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# In case of duplicate IDs, only the first is an anchor.
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has_anchor = anchor_name and anchor_name not in anchors
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if has_bookmark or has_link or has_anchor:
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pos_x, pos_y, width, height = box.hit_area()
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if has_link:
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link_type, target = link
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if matrix:
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link = _TaggedTuple(
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(link_type, target, rectangle_aabb(
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matrix, pos_x, pos_y, width, height)))
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else:
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link = _TaggedTuple(
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(link_type, target, (pos_x, pos_y, width, height)))
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link.sourceline = box.sourceline
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links.append(link)
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if matrix and (has_bookmark or has_anchor):
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pos_x, pos_y = matrix.transform_point(pos_x, pos_y)
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if has_bookmark:
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bookmarks.append((bookmark_level, bookmark_label, (pos_x, pos_y)))
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if has_anchor:
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anchors[anchor_name] = pos_x, pos_y
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def _prepare(box, bookmarks, links, anchors, matrix):
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transform = _get_matrix(box)
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if transform:
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matrix = transform * matrix if matrix else transform
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_get_metadata(box, bookmarks, links, anchors, matrix)
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for child in box.all_children():
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_prepare(child, bookmarks, links, anchors, matrix)
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class Page(object):
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"""Represents a single rendered page.
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.. versionadded:: 0.15
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Should be obtained from :attr:`Document.pages` but not
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instantiated directly.
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"""
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def __init__(self, page_box, enable_hinting=False):
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#: The page width, including margins, in CSS pixels.
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self.width = page_box.margin_width()
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#: The page height, including margins, in CSS pixels.
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self.height = page_box.margin_height()
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#: A list of ``(bookmark_level, bookmark_label, target)`` tuples.
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#: :obj:`bookmark_level` and :obj:`bookmark_label` are respectively
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#: an integer and an Unicode string, based on the CSS properties
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#: of the same names. :obj:`target` is a ``(x, y)`` point
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#: in CSS pixels from the top-left of the page.
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self.bookmarks = bookmarks = []
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#: A list of ``(link_type, target, rectangle)`` tuples.
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#: A rectangle is ``(x, y, width, height)``, in CSS pixels from
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#: the top-left of the page. :obj:`link_type` is one of two strings:
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#:
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#: * ``'external'``: :obj:`target` is an absolute URL
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#: * ``'internal'``: :obj:`target` is an anchor name (see
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#: :attr:`Page.anchors`). The anchor might be defined in
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#: another page, in multiple pages, or not at all.
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self.links = links = []
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#: A dict mapping anchor names to their target, ``(x, y)`` points
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#: in CSS pixels form the top-left of the page.)
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self.anchors = anchors = {}
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_prepare(page_box, bookmarks, links, anchors, matrix=None)
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self._page_box = page_box
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self._enable_hinting = enable_hinting
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def paint(self, cairo_context, left_x=0, top_y=0, scale=1, clip=False):
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"""Paint the surface in cairo, on any type of surface.
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:param cairo_context: any :class:`cairo.Context` object.
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:type left_x: float
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:param left_x:
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X coordinate of the left of the page, in cairo user units.
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:type top_y: float
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:param top_y:
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Y coordinate of the top of the page, in cairo user units.
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:type scale: float
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:param scale:
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Zoom scale in cairo user units per CSS pixel.
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:type clip: bool
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:param clip:
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Whether to clip/cut content outside the page. If false or
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not provided, content can overflow.
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"""
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with stacked(cairo_context):
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if self._enable_hinting:
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left_x, top_y = cairo_context.user_to_device(left_x, top_y)
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# Hint in device space
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left_x = int(left_x)
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top_y = int(top_y)
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left_x, top_y = cairo_context.device_to_user(left_x, top_y)
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# Make (0, 0) the top-left corner:
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cairo_context.translate(left_x, top_y)
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# Make user units CSS pixels:
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cairo_context.scale(scale, scale)
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if clip:
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width = self.width
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height = self.height
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if self._enable_hinting:
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width, height = (
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cairo_context.user_to_device_distance(width, height))
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# Hint in device space
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width = int(math.ceil(width))
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height = int(math.ceil(height))
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width, height = (
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cairo_context.device_to_user_distance(width, height))
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cairo_context.rectangle(0, 0, width, height)
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cairo_context.clip()
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draw_page(self._page_box, cairo_context, self._enable_hinting)
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class Document(object):
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"""A rendered document, with access to individual pages
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ready to be painted on any cairo surfaces.
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.. versionadded:: 0.15
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Should be obtained from :meth:`HTML.render() <weasyprint.HTML.render>`
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but not instantiated directly.
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"""
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@classmethod
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def _render(cls, html, stylesheets, enable_hinting):
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style_for = get_all_computed_styles(html, user_stylesheets=[
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css if hasattr(css, 'rules')
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else CSS(guess=css, media_type=html.media_type)
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for css in stylesheets or []])
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get_image_from_uri = functools.partial(
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images.get_image_from_uri, {}, html.url_fetcher)
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page_boxes = layout_document(
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enable_hinting, style_for, get_image_from_uri,
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build_formatting_structure(
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html.root_element, style_for, get_image_from_uri))
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return cls([Page(p, enable_hinting) for p in page_boxes])
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def __init__(self, pages):
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#: A list of :class:`Page` objects.
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self.pages = pages
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def copy(self, pages='all'):
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"""Take a subset of the pages.
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:param pages:
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An iterable of :class:`Page` objects from :attr:`pages`.
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:return:
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A new :class:`Document` object.
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Examples::
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# Lists count from 0 but page numbers usually from 1
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# [::2] is a slice of even list indexes but odd-numbered pages.
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document.copy(document.pages[::2]).write_pdf('odd_pages.pdf')
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document.copy(document.pages[1::2]).write_pdf('even_pages.pdf')
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for i, page in enumerate(document.pages):
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document.copy(page).write_png('page_%s.png' % i)
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"""
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if pages == 'all':
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pages = self.pages
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elif not isinstance(pages, list):
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pages = list(pages)
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return type(self)(pages)
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def resolve_links(self):
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"""Resolve internal hyperlinks.
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Links to a missing anchor are removed with a warning.
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If multiple anchors have the same name, the first is used.
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:returns:
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A generator yielding lists (one per page) like :attr:`Page.links`,
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except that :obj:`target` for internal hyperlinks is
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``(page_number, x, y)`` instead of an anchor name.
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The page number is an index (0-based) in the :attr:`pages` list,
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``x, y`` are in CSS pixels from the top-left of the page.
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"""
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anchors = {}
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for i, page in enumerate(self.pages):
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for anchor_name, (point_x, point_y) in iteritems(page.anchors):
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anchors.setdefault(anchor_name, (i, point_x, point_y))
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for page in self.pages:
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page_links = []
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for link in page.links:
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link_type, anchor_name, rectangle = link
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if link_type == 'internal':
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target = anchors.get(anchor_name)
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if target is None:
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LOGGER.warn(
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'No anchor #%s for internal URI reference '
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'at line %s' % (anchor_name, link.sourceline))
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else:
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page_links.append((link_type, target, rectangle))
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else:
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# External link
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page_links.append(link)
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yield page_links
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def make_bookmark_tree(self):
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"""Make a tree of all bookmarks in the document.
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:return: a list of bookmark subtrees.
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A subtree is ``(label, target, children)``. :obj:`label` is
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a string, :obj:`target` is ``(page_number, x, y)`` like in
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:meth:`resolve_links`, and :obj:`children` is itself a (recursive)
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list of subtrees.
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"""
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root = []
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# At one point in the document, for each "output" depth, how much
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# to add to get the source level (CSS values of bookmark-level).
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# Eg. with <h1> then <h3>, level_shifts == [0, 1]
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# 1 means that <h3> has depth 3 - 1 = 2 in the output.
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skipped_levels = []
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last_by_depth = [root]
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previous_level = 0
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for page_number, page in enumerate(self.pages):
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for level, label, (point_x, point_y) in page.bookmarks:
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if level > previous_level:
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# Example: if the previous bookmark is a <h2>, the next
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# depth "should" be for <h3>. If now we get a <h6> we’re
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# skipping two levels: append 6 - 3 - 1 = 2
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skipped_levels.append(level - previous_level - 1)
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else:
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temp = level
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while temp < previous_level:
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temp += 1 + skipped_levels.pop()
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if temp > previous_level:
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# We remove too many "skips", add some back:
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skipped_levels.append(temp - previous_level - 1)
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previous_level = level
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depth = level - sum(skipped_levels)
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assert depth == len(skipped_levels)
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assert depth >= 1
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children = []
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subtree = label, (page_number, point_x, point_y), children
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last_by_depth[depth - 1].append(subtree)
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del last_by_depth[depth:]
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last_by_depth.append(children)
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return root
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def write_pdf(self, target=None):
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"""Paint the pages in a PDF file, with meta-data.
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PDF files written directly by cairo do not have meta-data such as
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bookmarks/outlines and hyperlinks.
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:param target:
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A filename, file-like object, or :obj:`None`.
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:returns:
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The PDF as byte string if :obj:`target` is :obj:`None`, otherwise
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:obj:`None` (the PDF is written to :obj:`target`.)
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"""
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# Use an in-memory buffer. We will need to seek for metadata
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# TODO: avoid this if target can seek? Benchmark first.
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file_obj = io.BytesIO()
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# (1, 1) is overridden by .set_size() below.
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surface = cairo.PDFSurface(file_obj, 1, 1)
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context = cairo.Context(surface)
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for page in self.pages:
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surface.set_size(page.width * 0.75, page.height * 0.75)
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# 0.75 = 72 PDF point per inch / 96 CSS pixel per inch
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page.paint(context, scale=0.75)
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surface.show_page()
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surface.finish()
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write_pdf_metadata(self, file_obj)
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if target is None:
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return file_obj.getvalue()
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else:
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file_obj.seek(0)
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if hasattr(target, 'write'):
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shutil.copyfileobj(file_obj, target)
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else:
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with open(target, 'wb') as fd:
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shutil.copyfileobj(file_obj, fd)
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def write_png(self, target=None, resolution=96):
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"""Paint the pages vertically to a single PNG image.
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There is no decoration around pages other than those specified in CSS
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with ``@page`` rules. The final image is as wide as the widest page.
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Each page is below the previous one, centered horizontally.
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:param target:
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A filename, file-like object, or :obj:`None`.
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:type resolution: float
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:param resolution:
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The output resolution in PNG pixels per CSS inch. At 96 dpi
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(the default), PNG pixels match the CSS ``px`` unit.
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:returns:
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A ``(png_bytes, png_width, png_height)`` tuple. :obj:`png_bytes`
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is a byte string if :obj:`target` is :obj:`None`, otherwise
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:obj:`None` (the image is written to :obj:`target`.)
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:obj:`png_width` and :obj:`png_height` are the size of the
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final image, in PNG pixels.
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"""
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dppx = resolution / 96
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# This duplicates the hinting logic in Page.paint. There is a
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# dependency cycle otherwise:
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# this → hinting logic → context → surface → this
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# But since we do no transform here, cairo_context.user_to_device and
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# friends are identity functions.
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widths = [int(math.ceil(p.width * dppx)) for p in self.pages]
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heights = [int(math.ceil(p.height * dppx)) for p in self.pages]
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max_width = max(widths)
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sum_heights = sum(heights)
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surface = cairo.ImageSurface(
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cairo.FORMAT_ARGB32, max_width, sum_heights)
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context = cairo.Context(surface)
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pos_y = 0
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for page, width, height in izip(self.pages, widths, heights):
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pos_x = (max_width - width) / 2
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page.paint(context, pos_x, pos_y, scale=dppx, clip=True)
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pos_y += height
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if target is None:
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target = io.BytesIO()
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surface.write_to_png(target)
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png_bytes = target.getvalue()
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else:
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if sys.version_info[0] < 3 and isinstance(target, unicode):
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# py2cairo 1.8 does not support unicode filenames.
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target = target.encode(FILESYSTEM_ENCODING)
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surface.write_to_png(target)
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png_bytes = None
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return png_bytes, max_width, sum_heights
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