CVG - Compressed Vector Graphics

Compressed Vector Graphics (CVG) is an alternative format for encoding vector graphics which is based on interoperability with SVG. Essentially, it transforms SVG for optimized over-the-wire transmission, and usage within JavaScript environments. It does this by converting SVG's XML nodes into a JSON structure with some liberties taken in flexibility for short-hand declarations.

[!WARNING] Not for production use yet as it is still a heavy work-in-progress.

npm install --save @novafex/cvg
yarn add @novafex/cvg

Implementations

It's suggested to use the CLI for use in transforming files locally in your shell. For React projects there is a simple component react-cvg which expands CVG into the SVG for use in browsers.

Format

The CVG format is based on JSON objects makes heavy usage of tuples and dynamic types. There are TypeScript definitions for use with other libraries as well that will help.

A CVG "definition" is held as an array, the first element is the root declaration which declares the attributes within the root SVG node. After the root declaration, the remaining elements are children of the root node.

Root Declaration

The root declaration accepts variable types depending on how much definition is needed. As is the whole point of CVG, using the least amount of information is the target.

CVGRoot = CVGViewport | object
CVGViewport = string | [number, number] | [number, number, number, number]

• string will use the contents as the viewport attribute on the root node.
• [number, number] interprets as [width, height] for the viewport attribute and will set the position parts as 0.
• [number, number, number, number] interprets as [x, y, width, height] and will construct the viewport attribute using all values.
• object should be a string indexible object in which each attribute is declared as properties in it. They are passed through directly.

Children

After the root declaration, the remaining elements in the CVG definition are considered children of the root element and define the parts of the graphic.

CVGChild = string | CVGElement
CVGElement = [ string, object, string? ]

If the child is a string type, it is treated as short-hand for a path node with a d path definition being supplied by the string. This makes it easier for quick path-only icons. The contents of the string are taken directly.

For more flexibility, the element can be declared manually with a tuple containing looking like [tag, attributes, innerContent]. The tag is a string representing the SVG tag name such as "path", or "circle". The attributes object is a string- indexable record containing the attributes as key/value properties. Finally, the last innerContent portion is for injection of text inside the node and is used for style tags or other text block elements.

[!WARNING] There is a known limitation in which groups and nested elements are not implemented yet. They will be added, but the current version does not handle it.

Credits

Created and written by Chris Pikul

License

MIT License

Copyright (c) 2023 Novafex Technologies

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