Add page-break-inside: avoid

CHANGES

@@ -2,6 +2,7 @@ Version 0.7, released on 2012-XX-XX
 ===================================
 
 * Support for the ``orphans`` and ``widows`` properties.
+* Support for ``page-break-inside: avoid``
 
 
 Version 0.6.1, released on 2012-03-01

weasyprint/css/validation.py

@@ -629,9 +629,7 @@ def page_break(keyword):
 @single_keyword
 def page_break_inside(keyword):
     """Validation for the ``page-break-inside`` property."""
-    if keyword == 'avoid':
-        raise InvalidValues('value not supported yet')
-    return keyword  ('auto',)
+    return keyword in ('auto', 'avoid')
 
 
 @validator()

weasyprint/layout/blocks.py

@@ -258,7 +258,7 @@ def block_level_height(document, box, max_position_y, skip_stack,
             if is_page_break:
                 break
         else:
-            if new_children and not page_is_empty:
+            if new_children:
                 # between siblings, but not before the first child
                 # or after the last child.
                 break_here, next_page = forced_page_break(
@@ -271,7 +271,8 @@ def block_level_height(document, box, max_position_y, skip_stack,
             (new_child, resume_at, next_page, next_adjoining_margins,
                 collapsing_through) = block_level_layout(
                     document, child, max_position_y, skip_stack,
-                    new_containing_block, device_size, page_is_empty,
+                    new_containing_block, device_size,
+                    page_is_empty and not new_children,
                     adjoining_margins)
             skip_stack = None
 
@@ -293,7 +294,8 @@ def block_level_height(document, box, max_position_y, skip_stack,
                     new_position_y = (
                         new_child.border_box_y() + new_child.border_height())
 
-                    if (new_position_y > max_position_y and not page_is_empty
+                    if (new_position_y > max_position_y and (
+                                new_children or not page_is_empty)
                             and not isinstance(child, boxes.BlockBox)):
                         # The child overflows the page area, put it on the
                         # next page. (But don’t delay whole blocks if eg.
@@ -314,7 +316,6 @@ def block_level_height(document, box, max_position_y, skip_stack,
             # Bottom borders may overflow here
             # TODO: back-track somehow when all lines fit but not borders
             new_children.append(new_child)
-            page_is_empty = False
             if resume_at is not None:
                 resume_at = (index, resume_at)
                 break
@@ -322,6 +323,10 @@ def block_level_height(document, box, max_position_y, skip_stack,
     else:
         resume_at = None
 
+    if resume_at is not None and box.style.page_break_inside == 'avoid' \
+            and not page_is_empty:
+        return None, None, 'any', [], False
+
 
     if collapsing_with_children:
         if new_children and not isinstance(

weasyprint/tests/test_layout.py

@@ -641,16 +641,16 @@ def test_page_breaks():
 
 
 @assert_no_logs
-def test_orphans_widows():
+def test_orphans_widows_avoid():
     """Test orphans and widows control."""
-    def line_distribution(orphans, widows):
+    def line_distribution(css):
         pages = parse('''
             <style>
                 @page { -weasy-size: 200px }
                 h1 { height: 120px }
                 p { line-height: 20px;
                     width: 1px; /* line break at each word */
-                    orphans: %s; widows: %s }
+                    %s }
             </style>
             <h1>Tasty test</h1>
             <!-- There is room for 4 lines after h1 on the fist page -->
@@ -663,7 +663,7 @@ def test_orphans_widows():
                 six
                 seven
             </p>
-        ''' % (orphans, widows))
+        ''' % css)
         line_counts = []
         for i, page in enumerate(pages):
             html, = page.children
@@ -679,10 +679,13 @@ def test_orphans_widows():
                 line_counts.append(0)
         return line_counts
 
-    assert line_distribution(orphans=2, widows=2) == [4, 3]
-    assert line_distribution(orphans=5, widows=2) == [0, 7]
-    assert line_distribution(orphans=2, widows=4) == [3, 4]
-    assert line_distribution(orphans=4, widows=4) == [0, 7]
+    assert line_distribution('orphans: 2; widows: 2') == [4, 3]
+    assert line_distribution('orphans: 5; widows: 2') == [0, 7]
+    assert line_distribution('orphans: 2; widows: 4') == [3, 4]
+    assert line_distribution('orphans: 4; widows: 4') == [0, 7]
+
+    assert line_distribution(
+        'orphans: 2; widows: 2; page-break-inside: avoid') == [0, 7]
 
 
 @assert_no_logs