1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
<!DOCTYPE html>
<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api-1/#dependency-cycles-via-relative-units" />
<meta name="assert" content="This test verifies that reference cycles via units are detected" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
function register_length(name, inherits=false) {
CSS.registerProperty({
name: name,
syntax: '<length>',
initialValue: '0px',
inherits: inherits
});
}
register_length('--font-size-em');
register_length('--font-size-rem');
register_length('--font-size-ex');
register_length('--font-size-ch');
register_length('--font-size-px');
register_length('--font-size-em-via-var');
register_length('--font-size-rem-via-var');
register_length('--font-size-ex-via-var');
register_length('--font-size-ch-via-var');
register_length('--font-size-em-inherited', true);
register_length('--font-size-ex-inherited', true);
register_length('--font-size-ch-inherited', true);
</script>
<style>
:root {
--unregistered-em: 10em;
--unregistered-rem: 10rem;
--unregistered-ex: 10ex;
--unregistered-ch: 10ch;
}
:root, #target {
--font-size-em: 2em;
--font-size-rem: 2rem;
--font-size-ex: 2ex;
--font-size-ch: 2ch;
--font-size-px: 42px;
--font-size-em-via-var: var(--unregistered-em);
--font-size-rem-via-var: var(--unregistered-rem);
--font-size-ex-via-var: var(--unregistered-ex);
--font-size-ch-via-var: var(--unregistered-ch);
}
#parent {
--font-size-em-inherited: 4em;
--font-size-ex-inherited: 4ex;
--font-size-ch-inherited: 4ch;
}
#target {
font-size: 11px;
}
</style>
<div id=parent>
<div id=target></div>
</div>
<div id=ref></div>
<script>
// Compute a dimension (e.g. 1em) given a certain fontSize.
function compute_dimension(dimension, fontSize, element = ref) {
try {
element.attributeStyleMap.set('font-size', fontSize);
element.attributeStyleMap.set('margin-bottom', dimension);
return getComputedStyle(element).marginBottom;
} finally {
element.attributeStyleMap.clear();
}
}
function assert_property_equals(name, value, element = target) {
var computedStyle = getComputedStyle(element);
assert_equals(computedStyle.getPropertyValue(name), value);
}
let unsetFontSize = compute_dimension('1em', 'unset');
add_result_callback(function(){
target.attributeStyleMap.clear();
document.documentElement.attributeStyleMap.clear();
});
test(function() {
target.style = 'font-size: var(--font-size-px);';
assert_property_equals('font-size', '42px');
assert_property_equals('--font-size-px', '42px');
}, 'Non-font-dependent variables can be used in font-size');
test(function() {
target.style = 'font-size: var(--font-size-em);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-em', '0px');
}, 'Lengths with em units may not be referenced from font-size');
test(function() {
target.style = 'font-size: var(--font-size-ex);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-ex', '0px');
}, 'Lengths with ex units may not be referenced from font-size');
test(function() {
target.style = 'font-size: var(--font-size-ch);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-ch', '0px');
}, 'Lengths with ch units may not be referenced from font-size');
test(function() {
target.style = 'font-size: var(--font-size-rem);';
let expected = compute_dimension('2rem', 'unset', document.documentElement);
assert_property_equals('--font-size-rem', expected);
assert_property_equals('font-size', expected);
}, 'Lengths with rem units may be referenced from font-size on non-root element');
test(function() {
let root = document.documentElement;
root.style = 'font-size: var(--font-size-rem);';
assert_property_equals('font-size', unsetFontSize, root);
assert_property_equals('--font-size-rem', '0px', root);
}, 'Lengths with rem units may not be referenced from font-size on root element');
test(function() {
target.style = 'font-size: var(--noexist, var(--font-size-em));';
assert_property_equals('font-size', unsetFontSize);
}, 'Fallback may not use font-relative units');
test(function() {
target.style = 'font-size: var(--font-size-em, 42px);';
assert_property_equals('font-size', unsetFontSize);
}, 'Fallback not triggered while inside em unit cycle');
test(function() {
target.style = 'font-size: var(--font-size-ex, 42px);';
assert_property_equals('font-size', unsetFontSize);
}, 'Fallback not triggered while inside ex unit cycle');
test(function() {
target.style = 'font-size: var(--font-size-ch, 42px);';
assert_property_equals('font-size', unsetFontSize);
}, 'Fallback not triggered while inside ch unit cycle');
test(function() {
let root = document.documentElement;
root.style = 'font-size: var(--font-size-rem, 42px);';
assert_property_equals('font-size', unsetFontSize, root);
root.style = 'font-size: unset;';
}, 'Fallback not triggered while inside rem unit cycle on root element');
test(function() {
target.style = 'font-size: var(--font-size-em-via-var);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-em-via-var', '0px');
}, 'Lengths with em units are detected via var references');
test(function() {
target.style = 'font-size: var(--font-size-ex-via-var);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-ex-via-var', '0px');
}, 'Lengths with ex units are detected via var references');
test(function() {
target.style = 'font-size: var(--font-size-ch-via-var);';
assert_property_equals('font-size', unsetFontSize);
assert_property_equals('--font-size-ch-via-var', '0px');
}, 'Lengths with ch units are detected via var references');
test(function() {
let root = document.documentElement;
root.style = 'font-size: var(--font-size-rem-via-var);';
assert_property_equals('font-size', unsetFontSize, root);
assert_property_equals('--font-size-rem-via-var', '0px', root);
root.style = 'font-size: unset';
}, 'Lengths with rem units are detected via var references');
test(function() {
let expected4em = compute_dimension('4em', 'unset');
target.style = 'font-size: var(--font-size-em-inherited);';
assert_property_equals('font-size', expected4em);
assert_property_equals('--font-size-em-inherited', expected4em);
}, 'Inherited lengths with em units may be used');
test(function() {
let expected4ex = compute_dimension('4ex', 'unset');
target.style = 'font-size: var(--font-size-ex-inherited);';
assert_property_equals('font-size', expected4ex);
assert_property_equals('--font-size-ex-inherited', expected4ex);
}, 'Inherited lengths with ex units may be used');
test(function() {
let expected4ch = compute_dimension('4ch', 'unset');
target.style = 'font-size: var(--font-size-ch-inherited);';
assert_property_equals('font-size', expected4ch);
assert_property_equals('--font-size-ch-inherited', expected4ch);
}, 'Inherited lengths with ch units may be used');
</script>
|
