Description
Identify supplied glyph records with explicitly unknown ink boxes; absence is not assumed to be an empty-space glyph.
A glyph’s advance moves the next placement origin; its ink box describes visible bounds relative to that origin. Ink can overhang the advance, and an unknown box differs from a known empty box. These tools use caller-supplied glyph IDs and metrics, placing a horizontal run by cumulative advances without shaping text.
Identify supplied glyph records with explicitly unknown ink boxes; absence is not assumed to be an empty-space glyph.
When to use this tool
Use this tool to identify supplied glyph records with explicitly unknown ink boxes; absence is not assumed to be an empty-space glyph.
How to use the tool and how it works
- Enter glyphsJson using the input definitions below. Serialize the JSON text fields in the decoded shape shown below.
- Run the operation. Resolve malformed-input errors before interpreting the result.
- Read result.indexes. Interpret signs, units, ordering and null values using the rules below.
Validate and place the glyph records, then return original indexes whose box is explicitly null, in source order.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| glyphsJson | JSON array of {id, advance, cluster, box} glyph records. id is a string; advance is finite and may be signed; cluster is an integer 0–8192; box is null or [minX,minY,maxX,maxY] with ordered finite bounds. | Text, at most 8,192 UTF-16 code units; the stated grammar and narrower limits also apply. |
These decoded examples show the structure of the JSON text fields. Supply each as its corresponding serialized JSON string.
{
"glyphsJson": [
{
"id": "a",
"advance": 4,
"cluster": 0,
"box": [
0,
-1,
3,
2
]
},
{
"id": "b",
"advance": 5,
"cluster": 1,
"box": null
}
]
}| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.indexes | Original indexes of records with an unknown null box. |
{
"input": {
"glyphsJson": "[{\"id\": \"a\", \"advance\": 4, \"cluster\": 0, \"box\": [0, -1, 3, 2]}, {\"id\": \"b\", \"advance\": 5, \"cluster\": 1, \"box\": null}]"
},
"output": {
"result": {
"indexes": [
1
]
}
}
}Limitations and assumptions
- Unknown ink bounds do not establish an empty glyph, missing glyph ID or font coverage failure.
- All advances, box coordinates, shifts and positional tolerances must share caller-defined metric units. Signed advances are accepted. Glyph records contain id, advance, integer cluster 0–8192 and box = null or [minX,minY,maxX,maxY] with ordered bounds.
- Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
- Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.
Alternative or Complementary methods
Obtain metrics and cluster mappings from the intended font/shaping system, then inspect the supplied observations. Use actual rendering when hinting, fallback choice or visible pixel extents matter.
References
Similar or alternative tools
- Glyph Box Run Extents
Union explicitly supplied glyph ink boxes placed by accumulated horizontal advances; missing boxes contribute no invented ink, no font shaping.
- Glyph Advance Run Tab Stop Placement
Place glyph-run tab positions at the next strictly greater explicit stop, then repeat a supplied positive interval after the last stop; no text shaping.