151 lines
5.8 KiB
Python
151 lines
5.8 KiB
Python
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"""Find anchors, links, bookmarks and inputs in documents."""
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import math
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from .formatting_structure import boxes
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from .layout.percent import percentage
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from .matrix import 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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Return its axis-aligned bounding box as ``(x1, y1, x2, y2)``.
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"""
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if not matrix:
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return pos_x, pos_y, pos_x + width, pos_y + height
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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_y2
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def gather_anchors(box, anchors, links, bookmarks, inputs, parent_matrix=None):
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"""Gather anchors and other data related to specific positions in PDF.
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Currently finds anchors, links, bookmarks and inputs.
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"""
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# Get box transformation matrix.
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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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# https://www.w3.org/TR/css-transforms-1/#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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offset_x = percentage(origin_x, border_width)
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offset_y = percentage(origin_y, border_height)
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origin_x = box.border_box_x() + offset_x
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origin_y = box.border_box_y() + offset_y
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matrix = Matrix(e=origin_x, f=origin_y)
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for name, args in box.style['transform']:
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a, b, c, d, e, f = 1, 0, 0, 1, 0, 0
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if name == 'scale':
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a, d = args
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elif name == 'rotate':
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a = d = math.cos(args)
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b = math.sin(args)
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c = -b
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elif name == 'translate':
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e = percentage(args[0], border_width)
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f = percentage(args[1], border_height)
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elif name == 'skew':
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b, c = math.tan(args[1]), math.tan(args[0])
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else:
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assert name == 'matrix'
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a, b, c, d, e, f = args
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matrix = Matrix(a, b, c, d, e, f) @ matrix
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box.transformation_matrix = (
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Matrix(e=-origin_x, f=-origin_y) @ matrix)
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if parent_matrix:
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matrix = box.transformation_matrix @ parent_matrix
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else:
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matrix = box.transformation_matrix
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else:
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matrix = parent_matrix
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bookmark_label = box.bookmark_label
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if box.style['bookmark_level'] == 'none':
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bookmark_level = None
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else:
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bookmark_level = box.style['bookmark_level']
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state = box.style['bookmark_state']
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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, boxes.LineBox))
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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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is_input = box.is_input()
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if has_bookmark or has_link or has_anchor or is_input:
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if is_input:
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pos_x, pos_y = box.content_box_x(), box.content_box_y()
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width, height = box.width, box.height
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else:
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pos_x, pos_y, width, height = box.hit_area()
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if has_link or is_input:
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rectangle = rectangle_aabb(matrix, pos_x, pos_y, width, height)
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if has_link:
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token_type, link = link
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assert token_type == 'url'
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link_type, target = link
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assert isinstance(target, str)
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if link_type == 'external' and box.is_attachment():
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link_type = 'attachment'
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links.append((link_type, target, rectangle, box))
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if is_input:
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inputs.append((box.element, box.style, rectangle))
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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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bookmark = (bookmark_level, bookmark_label, (pos_x, pos_y), state)
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bookmarks.append(bookmark)
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if has_anchor:
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anchors[anchor_name] = pos_x, pos_y
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for child in box.all_children():
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gather_anchors(child, anchors, links, bookmarks, inputs, matrix)
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def make_page_bookmark_tree(page, skipped_levels, last_by_depth,
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previous_level, page_number, matrix):
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"""Make a tree of all bookmarks in a given page."""
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for level, label, (point_x, point_y), state 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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point_x, point_y = matrix.transform_point(point_x, point_y)
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subtree = (label, (page_number, point_x, point_y), children, state)
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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 previous_level
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