Allow specifying column widths on tables

wagtail/admin/templates/wagtailadmin/tables/table.html

@@ -1,6 +1,11 @@
 {% load wagtailadmin_tags %}
 
 <table {% if table.classname %}class="{{ table.classname }}"{% endif %}>
+    {% if table.has_column_widths %}
+        {% for column in table.columns.values %}
+            <col {% if column.width %}width="{{ column.width }}"{% endif %} />
+        {% endfor %}
+    {% endif %}
     <thead>
         <tr>
             {% for column in table.columns.values %}

wagtail/admin/tests/ui/test_tables.py

@@ -40,6 +40,32 @@ class TestTable(TestCase):
             </table>
         ''')
 
+    def test_table_render_with_width(self):
+        data = [
+            {'first_name': 'Paul', 'last_name': 'Simon'},
+            {'first_name': 'Art', 'last_name': 'Garfunkel'},
+        ]
+
+        table = Table([
+            Column('first_name'),
+            Column('last_name', width='75%'),
+        ], data)
+
+        html = self.render_component(table)
+        self.assertHTMLEqual(html, '''
+            <table class="listing">
+                <col />
+                <col width="75%" />
+                <thead>
+                    <tr><th>First name</th><th>Last name</th></tr>
+                </thead>
+                <tbody>
+                    <tr><td>Paul</td><td>Simon</td></tr>
+                    <tr><td>Art</td><td>Garfunkel</td></tr>
+                </tbody>
+            </table>
+        ''')
+
     def test_title_column(self):
         root_page = Page.objects.filter(depth=2).first()
         blog = Site.objects.create(hostname='blog.example.com', site_name='My blog', root_page=root_page)

wagtail/admin/ui/tables.py

@@ -39,13 +39,14 @@ class Column(metaclass=MediaDefiningClass):
     header_template_name = "wagtailadmin/tables/column_header.html"
     cell_template_name = "wagtailadmin/tables/cell.html"
 
-    def __init__(self, name, label=None, accessor=None, classname=None, sort_key=None):
+    def __init__(self, name, label=None, accessor=None, classname=None, sort_key=None, width=None):
         self.name = name
         self.accessor = accessor or name
         self.label = label or capfirst(name.replace('_', ' '))
         self.classname = classname
         self.sort_key = sort_key
         self.header = Column.Header(self)
+        self.width = width
 
     def get_header_context_data(self, parent_context):
         """
@@ -208,6 +209,9 @@ class Table(Component):
         for instance in self.data:
             yield Table.Row(self.columns, instance)
 
+    def has_column_widths(self):
+        return any(column.width for column in self.columns.values())
+
     class Row(Mapping):
         # behaves as an OrderedDict whose items are the rendered results of
         # the corresponding column's format_cell method applied to the instance