Fix split table headers’ top border when rows are split

Author: liZe

tests/draw/test_table.py

@@ -728,6 +728,7 @@ def test_tables_9(assert_pixels):
         ______________________
         ______________________
         ______________________
+        ______________________
         _BBBBBBBBBBBBBBBBBBBB_
         _BBBBBBBBBBBBBBBBBBBB_
         _BBBBBBBBBBBBBBBBBBBB_
@@ -745,7 +746,6 @@ def test_tables_9(assert_pixels):
         ______________________
         ______________________
         ______________________
-        ______________________
     ''', '''
       <style>
         @page { size: 22px 18px; margin: 1px }
@@ -1235,3 +1235,71 @@ def test_tables_21(assert_pixels):
       <table>
         <tr><td>abc</td><td>abc</td></tr>
         <tr><td>abc</td><td></td></tr>''')
+
+
+@assert_no_logs
+def test_tables_22(assert_pixels):
+    assert_pixels('''
+      _________________________
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rBBBBBBBBBBrBBBBBBBBBBr_
+      _________________________
+      _________________________
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _________________________
+    ''', '''
+      <style>
+        @font-face { src: url(weasyprint.otf); font-family: weasyprint }
+        @page { size: 25px 9px; margin: 1px }
+        table { border-collapse: collapse; font: 2px/1 weasyprint }
+        td { background: blue; border: 1px solid red }
+      </style>
+      <table>
+        <thead><tr><td>abcde</td><td>abcde</td></tr></thead>
+        <tbody><tr><td>abc abc</td><td></td></tr></tbody>''')
+
+
+@pytest.mark.xfail
+@assert_no_logs
+def test_tables_23(assert_pixels):
+    assert_pixels('''
+      _________________________
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rBBBBBBBBBBrBBBBBBBBBBr_
+      _________________________
+      _________________________
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rKKKKKKKKKKrKKKKKKKKKKr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rKKKKKKBBBBrBBBBBBBBBBr_
+      _rrrrrrrrrrrrrrrrrrrrrrr_
+      _________________________
+      _________________________
+    ''', '''
+      <style>
+        @font-face { src: url(weasyprint.otf); font-family: weasyprint }
+        @page { size: 25px 9px; margin: 1px }
+        table { border-collapse: collapse; font: 2px/1 weasyprint }
+        td { background: blue; border: 1px solid red }
+        thead td { border-bottom: none }
+      </style>
+      <table>
+        <thead><tr><td>abcde</td><td>abcde</td></tr></thead>
+        <tbody><tr><td>abc abc</td><td></td></tr></tbody>''')

weasyprint/layout/table.py

@@ -15,15 +15,18 @@ def table_layout(context, table, bottom_space, skip_stack, containing_block,
         avoid_page_break, block_container_layout, block_level_page_break,
         find_earlier_page_break, force_page_break)
 
-    table.remove_decoration(start=skip_stack is not None, end=False)
+    has_header = table.children and table.children[0].is_header
+    has_footer = table.children and table.children[-1].is_footer
+    collapse = table.style['border_collapse'] == 'collapse'
+    remove_start_decoration = skip_stack is not None and not has_header
+    table.remove_decoration(remove_start_decoration, end=False)
 
     column_widths = table.column_widths
 
-    if table.style['border_collapse'] == 'separate':
-        border_spacing_x, border_spacing_y = table.style['border_spacing']
+    if collapse:
+        border_spacing_x = border_spacing_y = 0
     else:
-        border_spacing_x = 0
-        border_spacing_y = 0
+        border_spacing_x, border_spacing_y = table.style['border_spacing']
 
     column_positions = table.column_positions = []
     rows_left_x = table.content_box_x() + border_spacing_x
@@ -44,7 +47,7 @@ def table_layout(context, table, bottom_space, skip_stack, containing_block,
             column_positions.append(position_x)
         rows_width = rows_x - position_x
 
-    if table.style['border_collapse'] == 'collapse':
+    if collapse:
         table.skip_cell_border_top = False
         table.skip_cell_border_bottom = False
         split_cells = False
@@ -60,7 +63,7 @@ def table_layout(context, table, bottom_space, skip_stack, containing_block,
                 skipped_rows += len(group.children)
         else:
             skipped_rows = 0
-        if not split_cells:
+        if not split_cells and not has_header:
             _, horizontal_borders = table.collapsed_border_grid
             if horizontal_borders:
                 table.border_top_width = max(
@@ -149,9 +152,20 @@ def group_layout(group, position_y, bottom_space, page_is_empty,
                         cell_skip_stack = {len(cell.children): None}
                 else:
                     cell_skip_stack = None
-                if cell_skip_stack:
-                    cell.remove_decoration(start=True, end=False)
-                    if table.style['border_collapse'] == 'collapse':
+
+                # Adapt cell and table collapsing borders when a row is split
+                if cell_skip_stack and collapse:
+                    if has_header:
+                        # We have a header, we have to adapt the position of
+                        # the split cell to match the header’s bottom border
+                        header_rows = table.children[0].children
+                        if header_rows and header_rows[-1].children:
+                            cell.position_y += max(
+                                header.border_bottom_width
+                                for header in header_rows[-1].children)
+                    else:
+                        # We don’t have a header, we have to skip the
+                        # decoration at the top of the table when it’s drawn
                         table.skip_cell_border_top = True
 
                 # First try to render content as if there was already something
@@ -308,7 +322,7 @@ def group_layout(group, position_y, bottom_space, page_is_empty,
             page_is_empty = False
             skip_stack = None
 
-            if break_cell and table.style['border_collapse'] == 'collapse':
+            if break_cell and collapse and not has_footer:
                 table.skip_cell_border_bottom = True
 
             if break_cell or resume_at:
@@ -422,7 +436,7 @@ def all_groups_layout():
         else:
             header_footer_bottom_space = -inf
 
-        if table.children and table.children[0].is_header:
+        if has_header:
             header = table.children[0]
             header, resume_at, next_page = group_layout(
                 header, position_y, header_footer_bottom_space,
@@ -434,7 +448,7 @@ def all_groups_layout():
         else:
             header = None
 
-        if table.children and table.children[-1].is_footer:
+        if has_footer:
             footer = table.children[-1]
             footer, resume_at, next_page = group_layout(
                 footer, position_y, header_footer_bottom_space,
@@ -536,9 +550,9 @@ def get_column_cells(table, column):
         ([header] if header is not None else []) +
         new_table_children +
         ([footer] if footer is not None else []))
-    table.remove_decoration(
-        start=skip_stack is not None, end=resume_at is not None)
-    if table.style['border_collapse'] == 'collapse':
+    remove_end_decoration = resume_at is not None and not has_footer
+    table.remove_decoration(remove_start_decoration, remove_end_decoration)
+    if collapse:
         table.skipped_rows = skipped_rows
 
     # If the height property has a bigger value, just add blank space