File Spec

VGG File Specification defines how JSON files are fused together as a single file.

There are two forms of file format designed for VGG, namely

• Form 1: Zip of JSONs
• Form 2: Streaming binary blob (🚧)

Both forms are essentially equivalent, differing only in file size and usage scenarios. Form 2 is more compact and has better support for network streaming.

Form 1: Zip of JSONs

This is the simplest and most straightforward format, where a file conforming to VGG File Spec is simply a zip of all the associated JSONs. The widely adopted Zip Spec can be found in ISO/IEC 21320-1:2015 and many open source implementations are available.

Currently Daruma will produce .daruma file and VGG Runtime reads it. This .daruma file is actually of Form 1, with its own customization. The structure of a typical .daruma file looks like this after unzipping:

├── design.json
├── layout.json
├── resources
│   ├── 7cd240ad79432fb602658bbf2d4b6b573681df30.png
│   ├── a80205d7467dc0e5eafac1cba24ce53ca2ddfae6.png
│   └── c1dc652004616cba4640e452e5feca37a4357334.png
└── thumbnail
    └── thumbnail_500_256.png

where design.json conforms to VGG Vector Graphics Spec and layout.json conforms to VGG Layout Spec. The images files under resources directory are referenced in design.json in some filed, like the imageFileName field in PatternImageFill.

Form 2: Streaming binary blob (🚧)

This form is optimized for file size and network streaming. It is still in the design phase. It will be like the Kiwi format used by Figma.