Samsa-CLI

Samsa-CLI (samsa-cli.js) is a Node.js command-line utility for performing operations on variable fonts (VFs). It uses the Samsa-Core library, so it requires samsa-core.js, as well as Node.

Installing Node.js

Download Node.js for your platform.

Arguments

--instances "<instanceDef[;instanceDef]>"
Introduces a list of instance definitions, separated with “;”. Use quotes to avoid space and semicolon being handled incorrectly by the shell. An instance definition may be:

• A specific location in the font’s designspace, specifying axis tags and values in pairs (e.g. “wght 633 wdth 88 ital 1”).
• The special value “default”, which generates the default instance.
• The special value “named”, which generates all named instances in the font.
• The special value “stat”, which generates all possible combinations of axis values specified by the STAT table. For example, if a STAT table records 5 axis values for wght and 3 axis values for wdth, we get the 15 (=5*3) possible combinations of instances. Note that this can lead to the generation of very many instances in some fonts. Any Format 4 STAT values are also included.

--instance, -i
Synonyms for --instances.

--output, -o <filename>
Outfile filename, overrides default “samsa-instance”.

--optimize, -O <memory|speed|size>
Optimize for low memory, high speed, instance size (default = speed), comma-separated. Note that very large fonts may require the “memory” optimization.

--quiet, -q
Quiet mode, no console output.

--list, -l
List instances, do not write any files.

Examples

Print out this short help info:
% node samsa-cli.js

Make static fonts for all named instances:
% node samsa-cli.js Gingham.ttf --instances named

Make static fonts for all named instances (switching to short -i syntax):
% node samsa-cli.js Gingham.ttf -i named

Make static fonts for all named instances optimized for smaller output size and low memory usage:
% node samsa-cli.js Gingham.ttf -i named -O size,memory

Make static fonts for all stat instances:
% node samsa-cli.js SourceSans.ttf -i stat

Make a static font for the custom instance at wght 245, wdth 89:
% node samsa-cli.js Skia.ttf -i "wght 345 wdth 89"

Make a static font for the default instance:
% node samsa-cli.js Skia.ttf -i default

Make static fonts using multiple instance specifications separated with “;”:
% node samsa-cli.js Skia.ttf -i "named;stat;wght 345 wdth 89;wght 811 wdth 180;default"

Performance

Initial tests indicate that it is much faster (approx. 40x) than fontTools at instantiation.

Limitations

The static fonts exported are not yet production ready. Limitations include:

• no support for GSUB, GPOS, STAT, MVAR tables (GSUB and GPOS tables are identical to input font, MVAR data is ignored, is STAT data is not exported to static fonts)
• no support for Feature Variations (aka rvrn)
• sfnt table checksums are all set to zero
• the name table remains identical to the input font

Exporting production ready fonts will depend on improvements to samsa-core.js.