Merge pull request #2252 from Kozea/page-groups

Handle page groups

docs/api_reference.rst

@@ -419,6 +419,7 @@ to their position in the document:
 
     @page :nth(3) { background: red } /* Third page */
     @page :nth(2n+1) { background: green } /* Odd pages */
+    @page :nth(1 of chapter) { background: blue } /* First pages of chapters */
 
 You can also use `running elements`_ to put HTML boxes into the page margins
 (but the ``start`` parameter of ``element()`` is not supported).
@@ -430,8 +431,6 @@ pseudo-elements. You can also change the way footnotes are displayed using the
 ``footnote-display`` property (``compact`` is not supported), and influence
 over the rendering of difficult pages with ``footnote-policy``.
 
-Page groups (``:nth(X of pagename)`` pseudo-class) are not supported.
-
 .. _CSS Generated Content for Paged Media Module: https://www.w3.org/TR/css-gcpm-3/
 .. _Page selectors: https://www.w3.org/TR/css-gcpm-3/#document-page-selectors
 .. _running elements: https://www.w3.org/TR/css-gcpm-3/#running-elements

tests/css/test_pages.py

@@ -4,8 +4,8 @@
 import tinycss2
 
 from weasyprint import CSS
-from weasyprint.css import PageType, get_all_computed_styles, parse_page_selectors
-from weasyprint.layout.page import set_page_type_computed_styles
+from weasyprint.css import get_all_computed_styles, parse_page_selectors
+from weasyprint.layout.page import PageType, set_page_type_computed_styles
 
 from ..testing_utils import FakeHTML, assert_no_logs, render_pages, resource_path
 
@@ -26,57 +26,50 @@ def test_page():
           }
         ''')])
 
-    page_type = PageType(
-        side='left', first=True, blank=False, index=0, name='')
+    page_type = PageType(side='left', blank=False, name='', index=0, group_index=0)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type)
     assert style['margin_top'] == (5, 'px')
     assert style['margin_left'] == (10, 'px')
     assert style['margin_bottom'] == (10, 'px')
     assert style['color'] == (1, 0, 0, 1)  # red, inherited from html
 
-    page_type = PageType(
-        side='right', first=True, blank=False, index=0, name='')
+    page_type = PageType(side='right', blank=False, name='', index=0, group_index=0)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type)
     assert style['margin_top'] == (5, 'px')
     assert style['margin_left'] == (10, 'px')
     assert style['margin_bottom'] == (16, 'px')
     assert style['color'] == (0, 0, 1, 1)  # blue
 
-    page_type = PageType(
-        side='left', first=False, blank=False, index=1, name='')
+    page_type = PageType(side='left', blank=False, name='', index=1, group_index=1)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type)
     assert style['margin_top'] == (10, 'px')
     assert style['margin_left'] == (10, 'px')
     assert style['margin_bottom'] == (10, 'px')
     assert style['color'] == (1, 0, 0, 1)  # red, inherited from html
 
-    page_type = PageType(
-        side='right', first=False, blank=False, index=1, name='')
+    page_type = PageType(side='right', blank=False, name='', index=1, group_index=1)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type)
     assert style['margin_top'] == (10, 'px')
     assert style['margin_left'] == (10, 'px')
     assert style['margin_bottom'] == (16, 'px')
     assert style['color'] == (0, 0, 1, 1)  # blue
 
-    page_type = PageType(
-        side='left', first=True, blank=False, index=0, name='')
+    page_type = PageType(side='left', blank=False, name='', index=0, group_index=0)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type, '@top-left')
     assert style is None
 
-    page_type = PageType(
-        side='right', first=True, blank=False, index=0, name='')
+    page_type = PageType(side='right', blank=False, name='', index=0, group_index=0)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type, '@top-left')
     assert style['font_size'] == 20  # inherited from @page
     assert style['width'] == (200, 'px')
 
-    page_type = PageType(
-        side='right', first=True, blank=False, index=0, name='')
+    page_type = PageType(side='right', blank=False, name='', index=0, group_index=0)
     set_page_type_computed_styles(page_type, document, style_for)
     style = style_for(page_type, '@top-right')
     assert style['font_size'] == 10

tests/test_boxes.py

@@ -2,9 +2,9 @@
 
 import pytest
 
-from weasyprint.css import PageType, get_all_computed_styles
+from weasyprint.css import get_all_computed_styles
 from weasyprint.formatting_structure import boxes, build
-from weasyprint.layout.page import set_page_type_computed_styles
+from weasyprint.layout.page import PageType, set_page_type_computed_styles
 
 from .testing_utils import (  # isort:skip
     FakeHTML, assert_no_logs, assert_tree, capture_logs, parse, parse_all,
@@ -248,20 +248,14 @@ def test_whitespace():
 
 @assert_no_logs
 @pytest.mark.parametrize('page_type, top, right, bottom, left', (
-    (PageType(side='left', first=True, index=0, blank=None, name=None),
-     20, 3, 3, 10),
-    (PageType(side='right', first=True, index=0, blank=None, name=None),
-     20, 10, 3, 3),
-    (PageType(side='left', first=None, index=1, blank=None, name=None),
-     10, 3, 3, 10),
-    (PageType(side='right', first=None, index=1, blank=None, name=None),
-     10, 10, 3, 3),
-    (PageType(side='right', first=None, index=1, blank=None, name='name'),
-     5, 10, 3, 15),
-    (PageType(side='right', first=None, index=2, blank=None, name='name'),
-     5, 10, 1, 15),
-    (PageType(side='right', first=None, index=8, blank=None, name='name'),
-     5, 10, 2, 15),
+    (PageType('left', False, '', 0, 0), 20, 3, 3, 10),
+    (PageType('right', False, '', 0, 0), 20, 10, 3, 3),
+    (PageType('left', False, '', 1, 1), 10, 3, 3, 10),
+    (PageType('right', False, '', 1, 1), 10, 10, 3, 3),
+    (PageType('right', False, 'name', 1, 0), 5, 10, 3, 15),
+    (PageType('right', False, 'name', 1, 1), 5, 10, 4, 15),
+    (PageType('right', False, 'name', 2, 0), 5, 10, 1, 15),
+    (PageType('right', False, 'name', 8, 8), 5, 10, 2, 15),
 ))
 def test_page_style(page_type, top, right, bottom, left):
     document = FakeHTML(string='''
@@ -270,6 +264,7 @@ def test_page_style(page_type, top, right, bottom, left):
         @page name { margin-left: 15px; margin-top: 5px }
         @page :nth(3) { margin-bottom: 1px }
         @page :nth(5n+4) { margin-bottom: 2px }
+        @page :nth(2 of name) { margin-bottom: 4px }
         @page :first { margin-top: 20px }
         @page :right { margin-right: 10px; margin-top: 10px }
         @page :left { margin-left: 10px; margin-top: 10px }

weasyprint/css/__init__.py

@@ -39,7 +39,8 @@
     None, 'before', 'after', 'marker', 'first-line', 'first-letter',
     'footnote-call', 'footnote-marker')
 
-PageType = namedtuple('PageType', ['side', 'blank', 'first', 'index', 'name'])
+PageSelectorType = namedtuple(
+    'PageSelectorType', ['side', 'blank', 'first', 'index', 'name'])
 
 
 class StyleFor:
@@ -111,7 +112,7 @@ def __init__(self, html, sheets, presentational_hints, target_collector):
         # Only iterate on pseudo-elements that have cascaded styles. (Others
         # might as well not exist.)
         for element, pseudo_type in cascaded_styles:
-            if pseudo_type and not isinstance(element, PageType):
+            if pseudo_type:
                 self.set_computed_styles(
                     element, pseudo_type=pseudo_type,
                     # The pseudo-element inherits from the element.
@@ -169,8 +170,8 @@ def add_page_declarations(self, page_type):
         for sheet, origin, sheet_specificity in self._sheets:
             for _rule, selector_list, declarations in sheet.page_rules:
                 for selector in selector_list:
-                    specificity, pseudo_type, selector_page_type = selector
-                    if self._page_type_match(selector_page_type, page_type):
+                    specificity, pseudo_type, page_selector_type = selector
+                    if self._page_type_match(page_selector_type, page_type):
                         specificity = sheet_specificity or specificity
                         style = self._cascaded_styles.setdefault(
                             (page_type, pseudo_type), {})
@@ -188,23 +189,22 @@ def get_computed_styles(self):
         return self._computed_styles
 
     @staticmethod
-    def _page_type_match(selector_page_type, page_type):
-        if selector_page_type.side not in (None, page_type.side):
+    def _page_type_match(page_selector_type, page_type):
+        if page_selector_type.side not in (None, page_type.side):
             return False
-        if selector_page_type.blank not in (None, page_type.blank):
+        if page_selector_type.blank not in (None, page_type.blank):
             return False
-        if selector_page_type.first not in (None, page_type.first):
+        if page_selector_type.first not in (None, page_type.index == 0):
             return False
-        if selector_page_type.name not in (None, page_type.name):
+        if page_selector_type.name not in (None, page_type.name):
             return False
-        if selector_page_type.index is not None:
-            a, b, group = selector_page_type.index
-            # TODO: handle group
-            offset = page_type.index + 1 - b
-            if a == 0:
-                return offset == 0
-            else:
-                return offset / a >= 0 and not offset % a
+        if page_selector_type.index is not None:
+            a, b, name = page_selector_type.index
+            if name is not None and name != page_type.name:
+                return False
+            index = page_type.index if name is None else page_type.group_index
+            offset = index + 1 - b
+            return offset == 0 if a == 0 else (offset / a >= 0 and not offset % a)
         return True
 
 
@@ -834,7 +834,7 @@ def parse_page_selectors(rule):
                     for i, argument in enumerate(function.arguments):
                         if argument.type == 'ident' and argument.value == 'of':
                             nth = function.arguments[:i - 1]
-                            group = function.arguments[i:]
+                            group = function.arguments[i + 1:]
                             break
                     else:
                         nth = function.arguments
@@ -847,18 +847,14 @@ def parse_page_selectors(rule):
                     if group is not None:
                         group = [
                             token for token in group
-                            if token.type not in (
-                                'comment', 'whitespacespace')]
+                            if token.type not in ('comment', 'whitespace')]
                         if len(group) != 1:
                             return None
                         group, = group
                         if group.type != 'ident':
                             return None
                         group = group.value
 
-                        # TODO: handle page groups
-                        return None
-
                     types['index'] = (*nth_values, group)
                     # TODO: specificity is not specified yet
                     # https://github.com/w3c/csswg-drafts/issues/3524
@@ -993,14 +989,14 @@ def preprocess_stylesheet(device_media_type, base_url, stylesheet_rules, url_fet
                 continue
 
             ignore_imports = True
-            for page_type in data:
-                specificity = page_type.pop('specificity')
-                page_type = PageType(**page_type)
+            for page_data in data:
+                specificity = page_data.pop('specificity')
+                page_selector_type = PageSelectorType(**page_data)
                 content = tinycss2.parse_blocks_contents(rule.content)
                 declarations = list(preprocess_declarations(base_url, content))
 
                 if declarations:
-                    selector_list = [(specificity, None, page_type)]
+                    selector_list = [(specificity, None, page_selector_type)]
                     page_rules.append((rule, selector_list, declarations))
 
                 for margin_rule in content:
@@ -1011,7 +1007,8 @@ def preprocess_stylesheet(device_media_type, base_url, stylesheet_rules, url_fet
                         tinycss2.parse_blocks_contents(margin_rule.content)))
                     if declarations:
                         selector_list = [(
-                            specificity, f'@{margin_rule.lower_at_keyword}', page_type)]
+                            specificity, f'@{margin_rule.lower_at_keyword}',
+                            page_selector_type)]
                         page_rules.append((margin_rule, selector_list, declarations))
 
         elif rule.type == 'at-rule' and rule.lower_at_keyword == 'font-face':

weasyprint/layout/page.py

@@ -1,9 +1,10 @@
 """Layout for pages and CSS3 margin boxes."""
 
 import copy
+from collections import namedtuple
 from math import inf
 
-from ..css import PageType, computed_from_cascaded
+from ..css import computed_from_cascaded
 from ..formatting_structure import boxes, build
 from ..logger import PROGRESS_LOGGER
 from .absolute import absolute_box_layout, absolute_layout
@@ -13,6 +14,8 @@
 from .percent import resolve_percentages
 from .preferred import max_content_width, min_content_width
 
+PageType = namedtuple('PageType', ['side', 'blank', 'name', 'index', 'group_index'])
+
 
 class OrientedBox:
     @property
@@ -797,7 +800,7 @@ def set_page_type_computed_styles(page_type, html, style_for):
                 base_url=html.base_url)
 
 
-def remake_page(index, context, root_box, html):
+def remake_page(index, group_index, context, root_box, html):
     """Return one laid out page without margin boxes.
 
     Start with the initial values from ``context.page_maker[index]``.
@@ -817,7 +820,6 @@ def remake_page(index, context, root_box, html):
     # Don't modify actual page_maker[index] values!
     # TODO: should we store (and reuse) page_type in the page_maker?
     page_state = copy.deepcopy(initial_page_state)
-    first = index == 0
     if initial_next_page['break'] in ('left', 'right'):
         next_page_side = initial_next_page['break']
     elif initial_next_page['break'] in ('recto', 'verso'):
@@ -830,10 +832,14 @@ def remake_page(index, context, root_box, html):
         (next_page_side == 'left' and right_page) or
         (next_page_side == 'right' and not right_page) or
         (context.reported_footnotes and initial_resume_at is None))
-    next_page_name = '' if blank else initial_next_page['page']
+    name = '' if blank else initial_next_page['page']
+    if name not in group_index:
+        group_index.clear()
+        group_index[name] = 0
     side = 'right' if right_page else 'left'
-    page_type = PageType(side, blank, first, index, name=next_page_name)
+    page_type = PageType(side, blank, name, index, group_index[name])
     set_page_type_computed_styles(page_type, html, context.style_for)
+    group_index[name] += 1
 
     context.forced_break = (
         initial_next_page['break'] != 'any' or initial_next_page['page'])
@@ -892,6 +898,7 @@ def make_all_pages(context, root_box, html, pages):
     """
     i = 0
     reported_footnotes = None
+    group_i = {'': 0}
     while True:
         remake_state = context.page_maker[i][-1]
         if (len(pages) == 0 or
@@ -903,7 +910,7 @@ def make_all_pages(context, root_box, html, pages):
             remake_state['pages_wanted'] = False
             remake_state['anchors'] = []
             remake_state['content_lookups'] = []
-            page, resume_at = remake_page(i, context, root_box, html)
+            page, resume_at = remake_page(i, group_i, context, root_box, html)
             reported_footnotes = context.reported_footnotes
             yield page
         else: