Support mask-border shorthand property.

tests/css/test_expanders.py

@@ -454,6 +454,74 @@ def test_border_image_invalid(rule, reason):
     assert_invalid(f'border-image: {rule}', reason)
 
 
+@assert_no_logs
+@pytest.mark.parametrize('rule, result', (
+    ('url(border.png) 27', {
+        'mask_border_source': ('url', 'https://weasyprint.org/foo/border.png'),
+        'mask_border_slice': ((27, None),),
+    }),
+    ('url(border.png) 10 / 4 / 2 round stretch', {
+        'mask_border_source': ('url', 'https://weasyprint.org/foo/border.png'),
+        'mask_border_slice': ((10, None),),
+        'mask_border_width': ((4, None),),
+        'mask_border_outset': ((2, None),),
+        'mask_border_repeat': (('round', 'stretch')),
+    }),
+    ('10 // 2', {
+        'mask_border_slice': ((10, None),),
+        'mask_border_outset': ((2, None),),
+    }),
+    ('5.5%', {
+        'mask_border_slice': ((5.5, '%'),),
+    }),
+    ('stretch 2 url("border.png")', {
+        'mask_border_source': ('url', 'https://weasyprint.org/foo/border.png'),
+        'mask_border_slice': ((2, None),),
+        'mask_border_repeat': (('stretch',)),
+    }),
+    ('1/2 round', {
+        'mask_border_slice': ((1, None),),
+        'mask_border_width': ((2, None),),
+        'mask_border_repeat': (('round',)),
+    }),
+    ('none', {
+        'mask_border_source': ('none', None),
+    }),
+    ('url(border.png) 27 alpha', {
+        'mask_border_source': ('url', 'https://weasyprint.org/foo/border.png'),
+        'mask_border_slice': ((27, None),),
+        'mask_border_mode': 'alpha',
+    }),
+    ('url(border.png) 27 luminance', {
+        'mask_border_source': ('url', 'https://weasyprint.org/foo/border.png'),
+        'mask_border_slice': ((27, None),),
+        'mask_border_mode': 'luminance',
+    }),
+))
+def test_mask_border(rule, result):
+    assert expand_to_dict(f'mask-border: {rule}') == result
+
+
+@assert_no_logs
+@pytest.mark.parametrize('rule, reason', (
+    ('url(border.png) url(border.png)', 'multiple source'),
+    ('10 10 10 10 10', 'multiple slice'),
+    ('1 / 2 / 3 / 4', 'invalid'),
+    ('/1', 'invalid'),
+    ('/1', 'invalid'),
+    ('round round round', 'invalid'),
+    ('-1', 'invalid'),
+    ('1 repeat 2', 'multiple slice'),
+    ('1% // 1%', 'invalid'),
+    ('1 / repeat', 'invalid'),
+    ('', 'no value'),
+    ('alpha alpha', 'multiple mode'),
+    ('alpha luminance', 'multiple mode'),
+))
+def test_mask_border_invalid(rule, reason):
+    assert_invalid(f'mask-border: {rule}', reason)
+
+
 @assert_no_logs
 @pytest.mark.parametrize('rule, result', (
     ('12px My Fancy Font, serif', {

weasyprint/css/validation/expanders.py

@@ -18,8 +18,8 @@
     border_width, box, column_count, column_width, flex_basis, flex_direction,
     flex_grow_shrink, flex_wrap, font_family, font_size, font_stretch,
     font_style, font_weight, gap, grid_line, grid_template, line_height,
-    list_style_image, list_style_position, list_style_type, other_colors,
-    overflow_wrap, validate_non_shorthand)
+    list_style_image, list_style_position, list_style_type, mask_border_mode,
+    other_colors, overflow_wrap, validate_non_shorthand)
 
 EXPANDERS = {}
 
@@ -350,6 +350,72 @@ def expand_border_image(tokens, name, base_url):
             raise InvalidValues
 
 
+@expander('mask-border')
+@generic_expander('-outset', '-repeat', '-slice', '-source', '-width', '-mode',
+                  wants_base_url=True)
+def expand_mask_border(tokens, name, base_url):
+    """Expand the ``mask-border-*`` shorthand properties.
+
+    See https://drafts.fxtf.org/css-masking/#the-mask-border
+
+    """
+    tokens = list(tokens)
+    while tokens:
+        if border_image_source(tokens[:1], base_url):
+            yield '-source', [tokens.pop(0)]
+        elif mask_border_mode(tokens[:1]):
+            yield '-mode', [tokens.pop(0)]
+        elif border_image_repeat(tokens[:1]):
+            repeats = [tokens.pop(0)]
+            while tokens and border_image_repeat(tokens[:1]):
+                repeats.append(tokens.pop(0))
+            yield '-repeat', repeats
+        elif border_image_slice(tokens[:1]) or get_keyword(tokens[0]) == 'fill':
+            slices = [tokens.pop(0)]
+            while tokens and border_image_slice(slices + tokens[:1]):
+                slices.append(tokens.pop(0))
+            yield '-slice', slices
+            if tokens and tokens[0].type == 'literal' and tokens[0].value == '/':
+                # slices / *
+                tokens.pop(0)
+            else:
+                # slices other
+                continue
+            if not tokens:
+                # slices /
+                raise InvalidValues
+            if border_image_width(tokens[:1]):
+                widths = [tokens.pop(0)]
+                while tokens and border_image_width(widths + tokens[:1]):
+                    widths.append(tokens.pop(0))
+                yield '-width', widths
+                if tokens and tokens[0].type == 'literal' and tokens[0].value == '/':
+                    # slices / widths / slash *
+                    tokens.pop(0)
+                else:
+                    # slices / widths other
+                    continue
+            elif tokens and tokens[0].type == 'literal' and tokens[0].value == '/':
+                # slices / / *
+                tokens.pop(0)
+            else:
+                # slices / other
+                raise InvalidValues
+            if not tokens:
+                # slices / * /
+                raise InvalidValues
+            if border_image_outset(tokens[:1]):
+                outsets = [tokens.pop(0)]
+                while tokens and border_image_outset(outsets + tokens[:1]):
+                    outsets.append(tokens.pop(0))
+                yield '-outset', outsets
+            else:
+                # slash / * / other
+                raise InvalidValues
+        else:
+            raise InvalidValues
+
+
 @expander('background')
 def expand_background(tokens, name, base_url):
     """Expand the ``background`` shorthand property.