Fix the drawing order of fixed boxes

Cherry-picked from 568e0ae

Conflicts:
	weasyprint/layout/blocks.py
	weasyprint/layout/inlines.py

weasyprint/document.py

@@ -23,7 +23,7 @@ class Document(object):
     """Abstract output document."""
     def __init__(self, backend, dom, user_stylesheets, user_agent_stylesheets):
         self.backend = backend
-        self.fixed_boxes = []
+        self.current_page = None
         self.surface = backend.get_dummy_surface()
         self.dom = dom  #: lxml HtmlElement object
         self.user_stylesheets = user_stylesheets

weasyprint/formatting_structure/boxes.py

@@ -568,6 +568,7 @@ def __init__(self, page_type, style):
         # Page boxes are not linked to any element.
         super(PageBox, self).__init__(
             element_tag=None, sourceline=None, style=style, children=[])
+        self.fixed_boxes = []
 
     def __repr__(self):
         return '<%s %s>' % (type(self).__name__, self.page_type)

weasyprint/layout/__init__.py

@@ -25,6 +25,15 @@
 from .pages import make_all_pages, make_margin_boxes
 
 
+def layout_fixed_boxes(document, pages):
+    """Lay out and yield the fixed boxes of ``pages``."""
+    for page in pages:
+        for fixed_box in page.fixed_boxes:
+            fixed_box_for_page = fixed_box.copy()
+            absolute_layout(document, fixed_box_for_page, page)
+            yield fixed_box_for_page
+
+
 def layout_document(document, root_box):
     """Lay out the whole document.
 
@@ -38,14 +47,12 @@ def layout_document(document, root_box):
     pages = list(make_all_pages(document, root_box))
     page_counter = [1]
     counter_values = {'page': page_counter, 'pages': [len(pages)]}
-    for page in pages:
+    for i, page in enumerate(pages):
+        root_children = []
         root, = page.children
-        root_children = list(root.children)
-        for fixed_box in document.fixed_boxes:
-            fixed_box_for_page = fixed_box.copy()
-            absolute_layout(document, fixed_box_for_page, page)
-            root_children.append(fixed_box_for_page)
-
+        root_children.extend(layout_fixed_boxes(document, pages[:i]))
+        root_children.extend(root.children)
+        root_children.extend(layout_fixed_boxes(document, pages[i+1:]))
         root = root.copy_with_children(root_children)
         page.children = (root,) + tuple(
             make_margin_boxes(document, page, counter_values))

weasyprint/layout/blocks.py

@@ -240,16 +240,16 @@ def block_container_layout(document, box, max_position_y, skip_stack,
         child.position_y = position_y
 
         if not child.is_in_normal_flow():
-            if child.style.position in ('absolute', 'fixed'):
+            if child.is_absolutely_positioned():
                 child.position_y += collapse_margin(adjoining_margins)
                 placeholder = AbsolutePlaceholder(child)
-                if child.style.position == 'absolute':
-                    absolute_boxes.append(placeholder)
-                    new_children.append(placeholder)
-                else:
-                    document.fixed_boxes.append(placeholder)
-            else:
+                new_children.append(placeholder)
+                absolute_boxes.append(placeholder)
+                if child.style.position == 'fixed':
+                    document.current_page.fixed_boxes.append(placeholder)
+            elif child.is_floated():
                 # TODO: Floats
+                assert 0
                 new_children.append(child)
             continue
 
@@ -426,7 +426,10 @@ def block_container_layout(document, box, max_position_y, skip_stack,
     if new_box.style.position == 'relative':
         # New containing block, resolve the layout of the absolute descendants
         for absolute_box in absolute_boxes:
-            absolute_layout(document, absolute_box, new_box)
+            if absolute_box.style.position == 'absolute':
+                absolute_layout(document, absolute_box, new_box)
+            else:
+                absolute_layout(document, absolute_box, document.current_page)
 
     for child in new_box.children:
         relative_positioning(child, (new_box.width, new_box.height))

weasyprint/layout/inlines.py

@@ -543,17 +543,17 @@ def split_inline_box(document, box, position_x, max_x, skip_stack,
     for index, child in box.enumerate_skip(skip):
         child.position_y = box.position_y
         if not child.is_in_normal_flow():
-            if child.style.position in ('absolute', 'fixed'):
+            if child.is_absolutely_positioned():
                 child.position_x = position_x
                 placeholder = AbsolutePlaceholder(child)
                 line_placeholders.append(placeholder)
-                if child.style.position == 'absolute':
-                    absolute_boxes.append(placeholder)
-                    children.append(placeholder)
-                else:
-                    document.fixed_boxes.append(placeholder)
-            else:
+                children.append(placeholder)
+                absolute_boxes.append(placeholder)
+                if child.style.position == 'fixed':
+                    document.current_page.fixed_boxes.append(placeholder)
+            elif child.style.float in ('left', 'right'):
                 # TODO: Floats
+                assert 0
                 children.append(child)
             continue
 
@@ -616,7 +616,10 @@ def split_inline_box(document, box, position_x, max_x, skip_stack,
 
     if new_box.style.position == 'relative':
         for absolute_box in absolute_boxes:
-            absolute_layout(document, absolute_box, new_box)
+            if absolute_box.style.position == 'absolute':
+                absolute_layout(document, absolute_box, new_box)
+            else:
+                absolute_layout(document, absolute_box, document.current_page)
     return new_box, resume_at, preserved_line_break
 
 

weasyprint/layout/pages.py

@@ -466,7 +466,7 @@ def make_page(document, root_box, page_type, resume_at, content_empty):
     style = document.style_for(page_type)
     # Propagated from the root or <body>.
     style.overflow = root_box.viewport_overflow
-    page = boxes.PageBox(page_type, style)
+    document.current_page = page = boxes.PageBox(page_type, style)
 
     device_size = page.style.size
     page.outer_width, page.outer_height = device_size
@@ -504,11 +504,11 @@ def make_page(document, root_box, page_type, resume_at, content_empty):
     for absolute_box in absolute_boxes:
         absolute_layout(document, absolute_box, page)
 
-    page = page.copy_with_children(children)
+    document.current_page = page.copy_with_children(children)
 
     if content_empty:
         resume_at = previous_resume_at
-    return page, resume_at, next_page
+    return document.current_page, resume_at, next_page
 
 
 def make_all_pages(document, root_box):