svg-inplace-rasterize/README.md

Rasterize parts of an SVG to keep it animatable while reducing size and improving render time.

# SVG Inplace Rasterize

Rasterize parts of an SVG to keep it animatable while reducing size and improving render time.

### Getting started

```bash
npm i svg-inplace-rasterize # add -g to make cli available
```

```bash
svg-inplace-rasterize --input test/files/wiki-example.svg --output tmp/out.svg -m 3 --format webp
```

```javascript
const { InplaceRasterizer } = require('svg-inplace-rasterize');

const rasterizer = new InplaceRasterizer();

const stream = fs.createReadStream('file.svg');

const svg = await rasterizer.rasterize(stream, {
  multiplier: 3,
  filter: $ => $('g'), // Cheerio object
  format: 'webp'
});

fs.writeFile('out.svg', svg);
```

### Features

This library takes some elements in a SVG file, rasterizes them using LibRsvg, and replaces the original elements with `<image>` tags with data uris.

It uses Sharp to create WebP images from the PNG output of LibRsvg.

#### Filter

You can select which elements to rasterize by using the filter option. This library uses Cheerio, which has the same API as jQuery.

The CLI uses this function by default, which selects all elements with an id that have no children with ids:

```javascript
function($) {
  const x = $('*[id]:not([id$="!"])').toArray();
  return x.filter(el => !$(el).children('*[id]:not([id$="!"])').length);
}
```

### Building `librsvg`

If `librsvg` has to be built from scratch, libffi must be installed on your system, and in your `PKG_CONFIG_PATH`.

```bash
export PKG_CONFIG_PATH="/usr/local/Cellar/libffi/3.2.1/lib/pkgconfig:${PKG_CONFIG_PATH}"
```

### Requirements

- No `transform`s on elements that are rasterized, nor on their parents.

### Todo

- Support `transform` (very common on Inkscape files)

### Special characters

Applies to `leaf-with-id` and `leaf-with-id-illustrator`:

- Id ends with `@`: do not rasterize
- Id ends with `&`: force rasterize
- Id ends with `!`: act as if no id