Curved Label Character Spacing Along Path Calculator
Signed uniform extra intercharacter gap along caller measured path arclength; negative spacing retained, no glyph orientation or kerning model.
Description
Calculate the uniform extra gap between characters along a measured label path.
Characters placed along a curved map label occupy part of the available path. The unused path length can be distributed over the gaps between consecutive characters to estimate a uniform spacing adjustment.
When to use this tool
Calculate the uniform extra gap between characters along a measured label path. Use it when the input measurements and conventions below match the operation you need.
- Prepare pathLengthMm, glyphAdvanceTotalMm, characterCount, respecting the measurement basis and boundaries below.
- Compare the worked example with your intended operation before reusing its result.
How to use the tool and how it works
- Enter every field in the input table using the stated units and exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
For an integer characterCount from 2 to 1,000,000 and nonnegative path and glyph-advance lengths, extraGapMm equals (pathLengthMm minus glyphAdvanceTotalMm) divided by (characterCount minus 1). A negative result indicates the nominal advances exceed the path length.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| pathLengthMm | Path length mm. Millimeters. | Finite number; zero or greater |
| glyphAdvanceTotalMm | Glyph advance total mm. Millimeters. | Finite number; zero or greater |
| characterCount | Character count. | Integer; from 2 to 1000000 inclusive |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.extraGapMm | Extra gap mm; use the stated units and sign convention. |
{
"input": {
"pathLengthMm": 100,
"glyphAdvanceTotalMm": 80,
"characterCount": 5
},
"output": {
"result": {
"extraGapMm": 5
}
}
}Limitations and assumptions
- This is gap arithmetic, without shaping, kerning, curvature, glyph rotation or collision analysis. A negative gap does not establish that the label can be compressed legibly.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
For a map-layout decision, inspect the rendered map at its intended size as well as its numerical dimensions. For classification or coordinate work, retain the chosen boundary and coordinate conventions with the result. Compare the scope of the nearby tools below before substituting one.
References
Similar or alternative tools
- graticule tick spacing lookup
Retrieve a supplied graticule tick spacing degree selection reference record with its declared source, context and date.
- Label Placement Collision Overlap Detector Two Labels
Pairwise axis-aligned rectangular label collision area; glyph contours, rotations and global placement omitted.