Instances Calculator is a set of two apps for macOS:
- A commandline tool
calculate_instances - A GUI app
ShowMeInstances
The apps are tools that can help designers of variable OpenType fonts or of multi-axis font families distort the design space and then calculate the instance locations.
The tools are a bit experimental.
If you know what MultipleMaster or Variable Font is, it will be much easier to understand what this software does.
If you design or developing font in MM or VariableFont technology, sometimes happened that particular Masters does not fit to each other — i.e. BlackCondensed could be to wide to pair with ThinCondensed or BlackCondesed could have different ”blackness” than BlackExtended.
There are two ways to deal with problem: to redesign masters or set their coordiantes in nice-looking places.
But in this second approach setting coordinates for particular styles are became a bit harder: there are not anymore [Light, Extended] coordinates but [LightSlightlyChangedOnWidthAxis, ExtendedSlghtlyChangedOnWeightAxis].
Two dimensional font has four masters: ThinCondensed, BlackCondensed, ThinExtended and BlackExtended.
Let's say that generated instance ThinCondensed sholud be wider, BlackCondensed a little bit lighter, ThinExtended darker, and BlackExtedned not so wide and lighter. But what with restof instances? Which coordinates will be for NarrowBold? We need to set values for Narrow style at Width axis, separate for Light and Black edge and values for Weight axis, separate for Condensed and Extended edges. For two dimensions it's easy: it's just a point, where lines cross.
Fore more than two dimensions it bacame a little more complicated. First, each axis has 2^(n-1) edges, where n is equal to number of dimensions. Second, lines in more then two dimensions doesn't like to cross each other. Sometimes they do, but in most cases don't. But it's possible to find common point of each dimension hyperbolic paraboloids. So, this tool does.
-
Download and install Swift 5 Runtime Support for Command Line Tools — you’ll need it to run the
calculate_instancescommandline app. -
App and command line are in this folder
The ShowMeInstances GUI app lets you open an axesmatrix JSON file, shows it in the left pane, in the middle visualizes it, and in the right pane shows the instances JSON. The calculate_instances commandline tool takes the axesmatrix JSON file as input, and outputs the instances JSON file.
The axesmatrix file is a JSON file with a syntax very similar to the syntax used in FontLab 7.
Read the FontLab 7 documentation chapters Variations and Working with Font Variations to understand design space, axes, axis instances, and instances.
- Open FontLab 7. (You can download a 30-day fully-functional trial from FontLab’s website).
- Turn on Preferences > Editing > Copy FontLab JSON data as plain text
- Open your multi-axis font in FontLab.
- Go to File > Font Info > Axes
- Write your axis instances per axis.
- Click Copy Page (bottom-left corner)
- Paste the JSON representation of the axes into a text editor such as Atom or Sublime Text.
In FontLab 7, all axis instances are orthogonal — the same value is used at the min and the max end. So the JSON will look something like this:
{
"dataType":"com.fontlab.info.axes",
"axes":[
{
"name":"weight",
"shortName":"wt",
"tag":"wght",
"designMinimum":0,
"designMaximum":1000,
"minimum":0,
"maximum":1000,
"default":450,
"axisGraph":{
"0":0,
"1000":1000
},
"axisInstances":[
{
"name":"Book",
"value":250
},
{
"name":"(Regular)",
"value":450
},
{
"name":"Medium",
"value":600
},
{
"name":"Bold",
"value":900
}
]
},
{
"name":"width",
"shortName":"wd",
"tag":"wdth",
"designMinimum":0,
"designMaximum":1000,
"minimum":0,
"maximum":1000,
"default":400,
"axisGraph":{
"0":0,
"1000":1000
},
"axisInstances":[
{
"name":"Condensed",
"value":100
},
{
"name":"Narrow",
"value":350
},
{
"name":"(Normal)",
"value":650
},
{
"name":"Wide",
"value":950
}
]
}
]
}The axesmatrix JSON syntax is a subset of the above syntax, but instead of one value element, it uses a list of values. Each values list lists the values of a given axis instance on each “edge” of the design space.
For example: in 3 dimensional space [weight, width, contrast], axis weight has four egdes:
- 00 - minimum width , minimum contrast
- 01 - minimum width, maximum contrast
- 10 - maximum width, minimum contrast
- 11 - maximum width, maximum contrast
Each edge could have different style value. (It's a main reason why I made this software.)
Each 4-dimensional space axis has 8 edges, so it needs 8 values. Each 5-dimensional space axis has 16 edges, so it needs 16 values.
Order of values is a binary 0 for minimum, binary 1 for maximum , bit order is the same as an order of defined axes, but bit of actual axis is removed. (look up on example, 00, 01, 10, 11)
in short: number of values in each axisInstances entry must be equal 2^(dimensions - 1); 2 for 2-dimensional, 4 for 3-dimensional, 8 for 4-dimensional designspace.
if parameter distribution is used , values between first and last style could be set to whatever, they don't count, but array must have proper (1, 2, 4, 8, 16...) number of whatevers.
There can also be an experimental parameter distribution, which causes exponential disribution of styles. distribution = 1 makes linear spaces between styles.
calculate_instances and ShowMeInstances takes this JSON as input:
{
"axes":[
{
"shortName":"weight",
"designMinimum":0,
"designMaximum":1000,
"distribution" : 1.2,
"axisInstances":[
{
"name":"Book",
"values": [250, 100]
},
{
"name":"(Regular)",
"values": [0, 0]
},
{
"name":"Medium",
"values": [0, 0]
},
{
"name":"Bold",
"values": [900, 950]
}
]
},
{
"shortName":"width",
"designMinimum":0,
"designMaximum":1000,
"axisInstances":[
{
"name":"Condensed",
"values": [100, 50]
},
{
"name":"Narrow",
"values": [350, 300]
},
{
"name":"(Normal)",
"values": [650, 600]
},
{
"name":"Wide",
"values": [950, 950]
}
]
}
]
}If you save this JSON as yourfont.axesmatrix.json, you can use the command-line:
calculate_instances yourfont.axesmatrix.json outfont.instances.json
You will get back an instances JSON:
{
"instances" : [
{
"name" : "Book Condensed",
"tsn" : "Book Condensed",
"location" : {
"width" : 88,
"weight" : 236
}
},
{
"name" : "Book Narrow",
"tsn" : "Book Narrow",
"location" : {
"width" : 340,
"weight" : 198
}
},
{
"name" : "Book",
"tsn" : "Book",
"location" : {
"width" : 642,
"weight" : 153
}
},
{
"name" : "Book Wide",
"tsn" : "Book Wide",
"location" : {
"width" : 950,
"weight" : 107
}
},
{
"name" : "Condensed",
"tsn" : "Condensed",
"location" : {
"width" : 79,
"weight" : 416
}
},
{
"name" : "Narrow",
"tsn" : "Narrow",
"location" : {
"width" : 330,
"weight" : 392
}
},
{
"name" : "",
"tsn" : "",
"location" : {
"width" : 631,
"weight" : 362
}
},
{
"name" : "Wide",
"tsn" : "Wide",
"location" : {
"width" : 950,
"weight" : 332
}
},
{
"name" : "Medium Condensed",
"tsn" : "Medium Condensed",
"location" : {
"width" : 67,
"weight" : 647
}
},
{
"name" : "Medium Narrow",
"tsn" : "Medium Narrow",
"location" : {
"width" : 317,
"weight" : 640
}
},
{
"name" : "Medium",
"tsn" : "Medium",
"location" : {
"width" : 618,
"weight" : 632
}
},
{
"name" : "Medium Wide",
"tsn" : "Medium Wide",
"location" : {
"width" : 950,
"weight" : 623
}
},
{
"name" : "Bold Condensed",
"tsn" : "Bold Condensed",
"location" : {
"width" : 54,
"weight" : 902
}
},
{
"name" : "Bold Narrow",
"tsn" : "Bold Narrow",
"location" : {
"width" : 304,
"weight" : 915
}
},
{
"name" : "Bold",
"tsn" : "Bold",
"location" : {
"width" : 603,
"weight" : 930
}
},
{
"name" : "Bold Wide",
"tsn" : "Bold Wide",
"location" : {
"width" : 950,
"weight" : 947
}
}
],
"dataType" : "com.fontlab.info.instances"
}This is almost correct for FontLab 7.
Open the outfont.instances.json file in a text editor, replace the axis names weight and width with the 2-letter codes wt and wd. Copy the contents to the clipboard. Then in FontLab 7, go to Font Info > Instances and click the Paste page button (3rd in the bottom-left). This will get the predefined instances into FontLab.
If you prefer UI, use ShowMeInstances app which is pretty experimental. But first prepare JSON in some editor. This app allwos you to change numbers, copy and delete parts of code, but has some limitations.
Rendering of distorted 5d designspace. 4th dimension is represented by blue color and 5th dimension is represented brightness
Rendering of distorted 6d designspace. 4th dimension is represented by hue, 5th by saturation, 6th by brightness.
Copyright 2019 Łukasz Dziedzic
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