/sqip

"SQIP" (pronounced \skwɪb\ like the non-magical folk of magical descent) is a SVG-based LQIP technique.

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This is the v1 alpha readme. You can find the current docs here.

SQIP - SVG-Based Image Placeholder

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"SQIP" (pronounced \skwɪb\ like the non-magical folk of magical descent) is a SVG-based LQIP technique.

SQIP will generate SVG based previews of images. They can be used as a lazy-loading image preview, a video thumbnail or an artistic element for your project.

SQIP is available as node API and CLI. It offers several plugins to allow creative image transformation options.

Table of contents

Examples

Requirements

Non-64bit operating systems requirements

After installing Primitive, you may also need to add the path to the Primitive binary file.

For macOS

It would generally look something like

/Users/myMacbook/go/bin

To do this on a Mac, type: sudo vim /etc/paths into your terminal, and add the path to your Primitive binary file, but be sure to add the full path, /Users/<username>/go/bin and not ~/go/bin.

For PC

Using the command line (https://www.windows-commandline.com/set-path-command-line)
Using a GUI (https://www.computerhope.com/issues/ch000549.htm)

Node

CLI see here

Installation

npm install sqip@canary sqip-plugin-primitive@canary sqip-plugin-svgo@canary sqip-plugin-data-uri@canary

This is the v1 alpha readme. Click here for v0 "stable" instructions.

Hint: SQIP is plugin based, you might want to install more plugins later on. See Plugins section.

Usage

SQIP is async.

try {
  const result = await sqip({...options})
  console.log(result)
} catch (err) {
  console.error(err)
}

// or

sqip({...options})
  .then(result => console.log(result))
  .catch(error => console.error(error))

If you passed a single image to process, SQIP will return the following result object:

{
  svg: 'data:image/svg+xml;base64,...==',
  dimensions: {
    height: 640,
    width: 1024,
    type: 'jpg'
  }
}

Multiple input images will result in an array of result objects.

Process folder with default settings

import sqip from 'sqip'
import { resolve } from 'path'

;(async () => {
  try {
    // Process whole folder with default settings
    const folderResults = await sqip({
      input: resolve(__dirname, 'images/originals'),
      output: resolve(__dirname, 'images/previews')
    })
    console.log(folderResults)
  } catch (err) {
    console.log('Something went wrong generating the SQIP previews')
    console.error(err)
  }
})()

Use custom plugin config

This will run:

  • Primitive with custom settings
  • SVGO with default settings
;(async () => {
  const pluginResults = await sqip({
    input: resolve(__dirname, 'images/originals'),
    output: resolve(__dirname, 'images/previews')
    plugins: [
      {
        name: 'sqip-plugin-primitive',
        options: {
          numberOfPrimitives: 8,
          mode: 0,
        },
      },
      `sqip-plugin-svgo`,
    ],
  })
  console.log(pluginResults)
})()

For further configuration options see here

CLI

Installation

npm install -g sqip-cli@canary

This is the v1 alpha readme. You can find the current docs here.

Usage examples

Using the help efficently

Make sure to specify plugins when using --help to see the available plugin options.

sqip -h -p primitive -p blur -p svgo
Result: 
sqip CLI

  Usage: sqip --input [path]

  "SQIP" (pronounced skwɪb like the non-magical folk of magical descent) is a
  SVG-based LQIP technique - https://github.com/technopagan/sqip

Options

  -h, --help                                  Show help
  --version                                   Show version number
  -p, --plugins string[]                      One or more plugins. E.g. "-p primitive blur"
  -i, --input string
  -o, --output string                         Save the resulting SVG to a file. The svg result will be returned by default.
  -n, --primitive-numberOfPrimitives number   The number of primitive shapes to use to build the SQIP SVG
  -m, --primitive-mode number                 The style of primitives to use:
                                              0=combo, 1=triangle, 2=rect, 3=ellipse, 4=circle, 5=rotatedrect, 6=beziers,
                                              7=rotatedellipse, 8=polygon
  -b, --blur-blur number                      Set the GaussianBlur SVG filter value. Disable it via 0.

Examples

  Output input.jpg image as SQIP
  $ sqip --input /path/to/input.jpg

  Save input.jpg as result.svg with 25 shapes and no blur
  $ sqip -i input.jpg -n 25 -b 0 -o result.svg

Process single file

sqip -input "demo/beach.jpg"
# <svg xmlns="http://www.w3.org/2000/svg" width="1024" height="640" viewBox="0 0 1024 640"><filter id="a"><feGaussianBlur stdDeviation="12"/></filter><rect width="100%" height="100%" fill="#718d95"/><g filter="url(#a)">...</g></svg>
Process multiple files via glob and use custom plugin config
sqip -p primitive -p blur -p svgo \
-i "demo/*.jpg" \
-b 6
# <svg>...</svg>
# <svg>...</svg>
# <svg>...</svg>
# <svg>...</svg>

For further configuration options see here

Config

The configuration consists of three parts. A required input, an optional output path and a configuration of plugins to be applied on the images.

input - required

Input file or directory. Supports feature rich globbing via micromatch.

CLI usage: -i/--input

output

If set, the output will be written to the given file or directory.

Otherwise, results will be output to CLI

CLI usage: -o/--output

width

Set the width of the resulting image. Negative values and 0 will fall back to the original image width.

CLI usage: -w/--width

plugins

Default: ['primitive', 'svgo']

Array of plugins. Either as a string (default config will be applied) or as a config object.

Example:

await sqip({
  ...
  plugins: [
    {
      name: 'sqip-plugin-primitive',
      options: {
        numberOfPrimitives: 8,
        mode: 0,
      },
    },
    `sqip-plugin-svgo`,
  ],
})

CLI usage:

-p/--plugins

  • Can be specified multiple times: -p svgo -p blur
  • If prefix was skipped, plugin names will be transformed to: sqip-plugin-[name]
  • To set plugin options, see plugin specifc config

Plugin specific config

  • See the Plugins section for a list of available plugins.
  • Follows the pattern --[plugin-name]-[option]=[value]

Example:

Set blur option of blur plugin to 3. You could use the -b shortcut as well.

sqip -i foo.jpg -p primitive -p blur -blur-blur 3

Plugins

SQIP comes with some core plugins, the community is very welcome to contribute their own plugins to SQIP.

Core plugins

Background & reseach

Image placeholders are a thing: from grey boxes in skeleton screens over boxes that show the predominant color of the image that will later occupy the space and CSS color gradients made from two dominant colors up to an actual low quality raster images downscaled to a few pixels, saved in low quality and then blurred to provide a preview of image contents.

Many major players have adopted one of these image placeholder techniques: Guypo incepted LQIP in 2012 and Akamai adopted it as part of their image optimization tools, Google started using colored placeholders a long time ago, Facebook, Pinterest and Medium made a significant impact on their LQIP implementations and the most popular JS libraries for responsive images include LQIP implementations.

Overview of Image Placeholder Techniques Overview of Image Placeholders

On the low end of the bytesize spectrum of image placeholder implementations, we have skeleton screens and colored boxes, weighing only a few extra bytes each, but providing no preview of image contents. On the high end of the bytesize spectrum, the LQIP technique ships an actual raster image, which gives a good initial impression of image contents to come, but weighs more heavily in bytesize.

If we disregard Facebooks's native-app implementation of shipping a custom image decoder that enables them to hardcode image headers, the current minimum bytesize for LQIP raster images is ~400-600 bytes. At this byterange, the preview image often looks distorted and coarse, especially on HiDPI screens. Many other LQIP implementations go for preview images of ~2kb in size, which provides a much better initial visual impression but comes at the cost of significantly increased bytesize for the LQIP implementation.

SQIP is an attempt to find a balance between these two extremes: it makes use of Primitive to generate a SVG consisting of several simple shapes that approximate the main features visible inside the image, optimizes the SVG using SVGO and adds a Gaussian Blur filter to it. This produces a SVG placeholder which weighs in at only ~800-1000 bytes, looks smooth on all screens and provides an visual cue of image contents to come.

Contributing

Contributor Covenant

Before contribution, please make sure to read the contribution guidelines guidelines and the code of conduct.

Pull requests, forks and stars are always welcome. For bugs and feature requests, please create an issue.

Credits

License

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to http://unlicense.org/