font-display Block/Swap Timeline Lookup
Qualitative font-display periods, no fixed universal millisecond durations or network completion guarantee. Explicit supplied computed/layout context only; not a browser cascade/layout engine or cross-browser guarantee.
Description
Font-display divides loading behavior into block and swap periods.
Font-display divides loading behavior into block and swap periods.1
Period names describe a strategy rather than fixed seconds measured for every browser. Use font-display Block/Swap Timeline Lookup to look up a supported term.
When to use font-display Block/Swap Timeline Lookup
Use font-display Block/Swap Timeline Lookup to look up a supported term. Choose the exact supported token from the table; preserve its punctuation and capitalization.
How to use font-display Block/Swap Timeline Lookup and understand its results
- Choose the exact supported token from the table; preserve its punctuation and capitalization.
- Enter Font display using the field table and validation rules below, then run the tool.
- Read Meaning and interpret units, signs, ordering and placeholders as explained below.
- If the tool reports an input error, correct that field and rerun. A successful false result, empty match list or unknown-evidence placeholder has the specific meaning described here; check the limitations before applying the result.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| fontDisplay | Font display | string | Required; constraints below |
Enter one of the exact supported fontDisplay tokens in the table below. The implementation performs a case-sensitive lookup and returns the stored meaning without interpreting a stylesheet, audio recording or performance. Unsupported tokens, added whitespace and alternate capitalization are input errors. The entries describe a bounded vocabulary rather than every valid value in the wider topic.
meaning = storedTable[exactSupportedToken] Field order, units and branch conditions follow the implementation explanation above.
| Exact supported token | Stored meaning |
|---|---|
| block | short block period then infinite swap period |
| swap | extremely small block period then infinite swap period |
| fallback | extremely small block period then short swap period |
| optional | extremely small block period and no swap period |
| auto | UA-defined loading strategy |
| Output field | Meaning | Value type |
|---|---|---|
| meaning | Stored explanation for the exact supported token. | string |
{
"input": {
"fontDisplay": "swap"
},
"output": {
"meaning": "extremely small block period then infinite swap period"
}
}Limitations and assumptions
Period names describe a strategy rather than fixed seconds measured for every browser. Apply the exact scope and assumptions described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are stated above; extremely large inputs or outputs can also be rejected. These errors differ from successful results such as false, no matches or unknown evidence.
Alternative or Complementary methods
Use image-rendering:pixelated Integer Scale Note for a related task: Integer scaling can map one source pixel to a uniform number of display pixels.
Use font-variant-numeric Tabular/Lining Lookup for a related task: Numeric font features distinguish digit width and digit form.
References
-
font-display Block/Swap Timeline Lookup — tool.io
Similar or alternative tools
- image-rendering:pixelated Integer Scale Note
Integer scaling can map one source pixel to a uniform number of display pixels.
- font-variant-numeric Tabular/Lining Lookup
Numeric font features distinguish digit width and digit form.