Gauging measurements in parametric designspaces
VariableValues is a growing set of tools to visualize and edit data across multiple designspace sources.
- Uses of parametric measurements
- Types of measurement
- Types of measurement points
- Types of scale
- Measurement validation
Uses of parametric measurements
- building parametric designspace (measurements as locations in parametric axes)
- visualizing and understanding glyph shape variation
- quality assurance, consistency, control
Types of measurement
Between 2 points
A measurement between two points can be horizontal, vertical, or angled (straight).
| direction | description |
|---|---|
| x | horizontal distance between two points |
| y | vertical distance between two points |
| a | straight distance between two points |
Between 1 point and 1 intersection
not implemented yet
Types of measurement points
| type | reference by | description | data type |
|---|---|---|---|
| curve point | point index | flat index number of the point | int |
| glyph margins | point index (out of range) | flat index number representing the left or right margin | int |
| vertical dimensions | short key | letter representing a vertical font dimension | str |
Curve point
Curve points are references by their flat index number, an index number that runs through all on- and off-curve points of a glyph without resetting at a new contour.
To display flat point indexes in RoboFont’s Glyph Editor, go to the Preferences Editor and set the value of the key indexesShouldFollowContour to 0.
Glyph margins
-
Vertical dimensions
…
Types of scale
Parent scale (p-scale)
The p-scale (A÷B) is the scale of a font-level measurement (A) in relation to its parent measurement (B).
Example:
| ref. | description | name | glyph | source |
|---|---|---|---|---|
A |
font-level measurement | XOLC |
n |
current |
B |
parent font-level measurement | XOPQ |
H |
current |
A÷B |
p-scale |
Font scale (f-scale)
The f-scale (A÷B) is the scale of a glyph-level measurement (A) in relation to the font-level value of the same name (B).
Example:
| ref. | description | name | glyph | source |
|---|---|---|---|---|
A |
glyph-level measurement | XOLC |
u |
current |
B |
font-level measurement | XOLC |
n |
current |
A÷B |
f-scale |
Default scale (d-scale)
The d-scale (A÷B) is the scale of a glyph-level measurement (A) in relation to the same measurement in the default font (B).
Example:
| ref. | description | name | glyph | source |
|---|---|---|---|---|
A |
glyph-level measurement | XOLC |
u |
current |
B |
glyph-level measurement | XOLC |
u |
default |
A÷B |
d-scale |
Measurement validation
| scale | treshold | validation against |
|---|---|---|
| p-scale | p-treshold | parent font-level measurement |
| f-scale | f-treshold | font-level measurement |
| d-scale | d-treshold | default glyph measurement |
Scale values can be used to validate glyph-level measurements against different types of reference values.
Each scale has a corresponding treshold value. Based on this value, a measurement can be considered either:
- equal to
- different within treshold
- different outside treshold