Split absolute boxes

Fix #36.

tests/draw/test_absolute.py

@@ -12,14 +12,13 @@
 from . import assert_pixels
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_absolute_split_1():
     expected_pixels = '''
         BBBBRRRRRRRR____
         BBBBRRRRRRRR____
-        BBBB____________
-        BBBB____________
+        BBBBRR__________
+        BBBBRR__________
     '''
     html = '''
         <style>
@@ -33,22 +32,23 @@ def test_absolute_split_1():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
+                left: 0;
                 position: absolute;
                 top: 0;
-                left: 0;
                 width: 4px;
             }
         </style>
         <div class="split">aa aa</div>
-        <div>bbbbbb bb</div>
+        <div>bbbbbb bbb</div>
     '''
     assert_pixels('absolute_split_1', 16, 4, expected_pixels, html)
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_absolute_split_2():
     expected_pixels = '''
@@ -69,6 +69,8 @@ def test_absolute_split_2():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -104,6 +106,8 @@ def test_absolute_split_3():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -139,6 +143,8 @@ def test_absolute_split_4():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -154,7 +160,6 @@ def test_absolute_split_4():
     assert_pixels('absolute_split_4', 16, 4, expected_pixels, html)
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_absolute_split_5():
     expected_pixels = '''
@@ -175,6 +180,8 @@ def test_absolute_split_5():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -197,7 +204,6 @@ def test_absolute_split_5():
     assert_pixels('absolute_split_5', 16, 4, expected_pixels, html)
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_absolute_split_6():
     expected_pixels = '''
@@ -218,6 +224,8 @@ def test_absolute_split_6():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -238,7 +246,6 @@ def test_absolute_split_6():
     assert_pixels('absolute_split_6', 16, 4, expected_pixels, html)
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_absolute_split_7():
     expected_pixels = '''
@@ -259,6 +266,8 @@ def test_absolute_split_7():
                 font-family: weasyprint;
                 font-size: 2px;
                 line-height: 1;
+                orphans: 1;
+                widows: 1;
             }
             div.split {
                 color: blue;
@@ -281,3 +290,48 @@ def test_absolute_split_7():
         <div class="push">bbbb bb</div>
     '''
     assert_pixels('absolute_split_7', 16, 4, expected_pixels, html)
+
+
+@pytest.mark.xfail
+@assert_no_logs
+def test_absolute_next_page():
+    # TODO: currently, the layout of absolute boxes forces to render a box,
+    # even when it doesn’t fit in the page. This workaround avoids placeholders
+    # with no box. Instead, we should remove these placeholders, or avoid
+    # crashes when they’re rendered.
+    expected_pixels = '''
+        RRRRRRRRRR______
+        RRRRRRRRRR______
+        RRRRRRRRRR______
+        RRRRRRRRRR______
+        BBBBBBRRRR______
+        BBBBBBRRRR______
+        BBBBBB__________
+        ________________
+    '''
+    html = '''
+        <style>
+            @font-face {src: url(weasyprint.otf); font-family: weasyprint}
+            @page {
+                background: white;
+                size: 16px 4px;
+            }
+            body {
+                color: red;
+                font-family: weasyprint;
+                font-size: 2px;
+                line-height: 1;
+                orphans: 1;
+                widows: 1;
+            }
+            div.split {
+                color: blue;
+                position: absolute;
+                font-size: 3px;
+            }
+        </style>
+        aaaaa aaaaa
+        <div class="split">bb</div>
+        aaaaa
+    '''
+    assert_pixels('absolute_next_page', 16, 8, expected_pixels, html)

tests/draw/test_float.py

@@ -393,7 +393,6 @@ def test_float_split_1():
     assert_pixels('float_split_1', 16, 4, expected_pixels, html)
 
 
-@pytest.mark.xfail
 @assert_no_logs
 def test_float_split_2():
     expected_pixels = '''

weasyprint/layout/__init__.py

@@ -91,13 +91,16 @@ def layout_fixed_boxes(context, pages, containing_page):
             # Absolute boxes in fixed boxes are rendered as fixed boxes'
             # children, even when they are fixed themselves.
             absolute_boxes = []
-            yield absolute_box_layout(
-                context, box, containing_page, absolute_boxes)
+            absolute_box, _ = absolute_box_layout(
+                context, box, containing_page, absolute_boxes,
+                bottom_space=-inf, skip_stack=None)
+            yield absolute_box
             while absolute_boxes:
                 new_absolute_boxes = []
                 for box in absolute_boxes:
                     absolute_layout(
-                        context, box, containing_page, new_absolute_boxes)
+                        context, box, containing_page, new_absolute_boxes,
+                        bottom_space=-inf, skip_stack=None)
                 absolute_boxes = new_absolute_boxes
 
 

weasyprint/layout/absolute.py

@@ -187,7 +187,8 @@ def absolute_height(box, context, containing_block):
     return translate_box_height, translate_y
 
 
-def absolute_block(context, box, containing_block, fixed_boxes):
+def absolute_block(context, box, containing_block, fixed_boxes, bottom_space,
+                   skip_stack):
     from .block import block_container_layout
 
     cb_x, cb_y, cb_width, cb_height = containing_block
@@ -203,13 +204,15 @@ def absolute_block(context, box, containing_block, fixed_boxes):
     if box.is_table_wrapper:
         table_wrapper_width(context, box, (cb_width, cb_height))
 
-    new_box, _, _, _, _ = block_container_layout(
-        context, box, bottom_space=-float('inf'), skip_stack=None,
-        page_is_empty=False, absolute_boxes=absolute_boxes,
-        fixed_boxes=fixed_boxes, adjoining_margins=None, discard=False)
+    new_box, resume_at, _, _, _ = block_container_layout(
+        context, box, bottom_space, skip_stack, page_is_empty=True,
+        absolute_boxes=absolute_boxes, fixed_boxes=fixed_boxes,
+        adjoining_margins=None, discard=False)
 
     for child_placeholder in absolute_boxes:
-        absolute_layout(context, child_placeholder, new_box, fixed_boxes)
+        absolute_layout(
+            context, child_placeholder, new_box, fixed_boxes, bottom_space,
+            skip_stack)
 
     if translate_box_width:
         translate_x -= new_box.width
@@ -218,11 +221,11 @@ def absolute_block(context, box, containing_block, fixed_boxes):
 
     new_box.translate(translate_x, translate_y)
 
-    return new_box
+    return new_box, resume_at
 
 
-def absolute_flex(context, box, containing_block_sizes, fixed_boxes,
-                  containing_block):
+def absolute_flex(context, box, containing_block, fixed_boxes, bottom_space,
+                  skip_stack, containing_block_sizes):
     from .flex import flex_layout
 
     # TODO: this function is really close to absolute_block, we should have
@@ -241,13 +244,15 @@ def absolute_flex(context, box, containing_block_sizes, fixed_boxes,
     if box.is_table_wrapper:
         table_wrapper_width(context, box, (cb_width, cb_height))
 
-    new_box, _, _, _, _ = flex_layout(
-        context, box, bottom_space=-float('inf'), skip_stack=None,
-        containing_block=containing_block, page_is_empty=False,
-        absolute_boxes=absolute_boxes, fixed_boxes=fixed_boxes)
+    new_box, resume_at, _, _, _ = flex_layout(
+        context, box, bottom_space, skip_stack, containing_block,
+        page_is_empty=True, absolute_boxes=absolute_boxes,
+        fixed_boxes=fixed_boxes)
 
     for child_placeholder in absolute_boxes:
-        absolute_layout(context, child_placeholder, new_box, fixed_boxes)
+        absolute_layout(
+            context, child_placeholder, new_box, fixed_boxes, bottom_space,
+            skip_stack)
 
     if translate_box_width:
         translate_x -= new_box.width
@@ -256,31 +261,37 @@ def absolute_flex(context, box, containing_block_sizes, fixed_boxes,
 
     new_box.translate(translate_x, translate_y)
 
-    return new_box
+    return new_box, resume_at
 
 
-def absolute_layout(context, placeholder, containing_block, fixed_boxes):
+def absolute_layout(context, placeholder, containing_block, fixed_boxes,
+                    bottom_space, skip_stack):
     """Set the width of absolute positioned ``box``."""
     assert not placeholder._layout_done
     box = placeholder._box
-    placeholder.set_laid_out_box(
-        absolute_box_layout(context, box, containing_block, fixed_boxes))
+    new_box, resume_at = absolute_box_layout(
+        context, box, containing_block, fixed_boxes, bottom_space, skip_stack)
+    placeholder.set_laid_out_box(new_box)
+    if resume_at:
+        context.broken_out_of_flow.append(
+            (box, containing_block, resume_at))
 
 
-def absolute_box_layout(context, box, containing_block, fixed_boxes):
-    cb = containing_block
+def absolute_box_layout(context, box, containing_block, fixed_boxes,
+                        bottom_space, skip_stack):
     # TODO: handle inline boxes (point 10.1.4.1)
     # http://www.w3.org/TR/CSS2/visudet.html#containing-block-details
     if isinstance(containing_block, boxes.PageBox):
-        cb_x = cb.content_box_x()
-        cb_y = cb.content_box_y()
-        cb_width = cb.width
-        cb_height = cb.height
+        cb_x = containing_block.content_box_x()
+        cb_y = containing_block.content_box_y()
+        cb_width = containing_block.width
+        cb_height = containing_block.height
     else:
-        cb_x = cb.padding_box_x()
-        cb_y = cb.padding_box_y()
-        cb_width = cb.padding_width()
-        cb_height = cb.padding_height()
+        cb_x = containing_block.padding_box_x()
+        cb_y = containing_block.padding_box_y()
+        cb_width = containing_block.padding_width()
+        cb_height = containing_block.padding_height()
+    original_containing_block = containing_block
     containing_block = cb_x, cb_y, cb_width, cb_height
 
     resolve_percentages(box, (cb_width, cb_height))
@@ -289,15 +300,19 @@ def absolute_box_layout(context, box, containing_block, fixed_boxes):
     context.create_block_formatting_context()
     # Absolute tables are wrapped into block boxes
     if isinstance(box, boxes.BlockBox):
-        new_box = absolute_block(context, box, containing_block, fixed_boxes)
+        new_box, resume_at = absolute_block(
+            context, box, containing_block, fixed_boxes,
+            bottom_space, skip_stack)
     elif isinstance(box, boxes.FlexContainerBox):
-        new_box = absolute_flex(
-            context, box, containing_block, fixed_boxes, cb)
+        new_box, resume_at = absolute_flex(
+            context, box, containing_block, fixed_boxes,
+            bottom_space, skip_stack, original_containing_block)
     else:
         assert isinstance(box, boxes.BlockReplacedBox)
         new_box = absolute_replaced(context, box, containing_block)
+        resume_at = None
     context.finish_block_formatting_context(new_box)
-    return new_box
+    return new_box, resume_at
 
 
 def absolute_replaced(context, box, containing_block):

weasyprint/layout/block.py

@@ -716,7 +716,9 @@ def block_container_layout(context, box, bottom_space, 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(context, absolute_box, new_box, fixed_boxes)
+            absolute_layout(
+                context, absolute_box, new_box, fixed_boxes, bottom_space,
+                skip_stack=None)
 
     for child in new_box.children:
         relative_positioning(child, (new_box.width, new_box.height))

weasyprint/layout/column.py

@@ -299,6 +299,8 @@ def create_column_box(children):
     if box.style['position'] == 'relative':
         # New containing block, resolve the layout of the absolute descendants
         for absolute_box in absolute_boxes:
-            absolute_layout(context, absolute_box, box, fixed_boxes)
+            absolute_layout(
+                context, absolute_box, box, fixed_boxes, bottom_space,
+                skip_stack=None)
 
     return box, skip_stack, next_page, [], False

weasyprint/layout/inline.py

@@ -864,7 +864,9 @@ def split_inline_box(context, box, position_x, max_x, bottom_space, skip_stack,
 
     if new_box.style['position'] == 'relative':
         for absolute_box in absolute_boxes:
-            absolute_layout(context, absolute_box, new_box, fixed_boxes)
+            absolute_layout(
+                context, absolute_box, new_box, fixed_boxes, bottom_space,
+                skip_stack=None)
 
     if resume_at is not None:
         index = tuple(resume_at)[0]