image-optim    

Node.js wrapper for image compression algorithms.

- Types
- Patches
- Overview
- Install
- Usage
- API
- imageOptim.optim
- imageOptim.lint
- Exit code
- SUCCESS
- CANT_COMPRESS
- DOESNT_EXIST
- Example
- CLI
- Example

Types

* PNG – PNGOUT, Zopflipng, Pngcrush, AdvPng and OptiPNG.

Supporting of other types of images is coming soon.

Patches

You can view all the _patches_ which are applied to the algorithms here.

#### Overview:

* optipng.patch – adds to OptiPNG the ability to remove _RGB_ components or transparent pixels in _RGB+alpha_ images.

* zopflipng.patch – makes Zopflipng work on _Linux_.

Install

``bash
$ npm install imageoptim
`

This command will install image-optim and all supported compression algorithms automatically. The installation of the compression algorithms is subscribed in script env-setup.

Usage

$3

`js
var imageOptim = require('imageoptim');
`

#### imageOptim.optim

Optimizes the given files.

@param {String[]} – a list of paths to files to optimize

@param {Object} – options:


reporters {String[]}* - reporters of the results. _flat_ - writes the results to stdout, _html_ - creates the HTML report of the results in file imageoptim-report.html (default: flat).

@returns {Promise Object[]}* – the information about optimized files:


`js
[{ name: 'file.ext', savedBytes: 12345, exitCode: 0 }]
`

#### imageOptim.lint

Checks whether the given files can be optimized further.

@param {String[]} – a list of paths to files to check

@param {Object} – options:


tolerance {Number}* – sets the measurement error in _percentages_ (decimal < 1) or _bytes_ (integer or decimal >= 1) (default: 0).

type | skope | description
--- | --- | ---
_percentages_ | < 1 | The file will be considered to be optimized if the percentage of saved bytes after the compression is less than the specified value (_0.8_ – 80%, _0.01_ – 1%, etc)
_bytes_ | >= 1 | The file will be considered to be optimized if the number of saved bytes after the compression is less than the specified value (_20_ – 20 bytes, _100500_ – 100500 bytes, etc)

reporters {String[]}* - reporters of the results. _flat_ - writes the results to stdout, _html_ - creates the HTML report of the results in file imageoptim-report.html (default: flat).

@returns {Promise Object[]}* – the information about linted files:


`js
[{ name: 'file.ext', isOptimized: true, exitCode: 0 }]
`

#### Exit code


##### imageOptim.SUCCESS

If a file was processed without errors its exit code will be equal to 0.


##### imageOptim.CANT_COMPRESS

If a file can not be processed by one of the algorithms its exit code will be equal to 1.


##### imageOptim.DOESNT_EXIST

If a file does not exist its exit code will be equal to 2.

#### Example

`js
var imageOptim = require('imageoptim');

// optimization
imageOptim.optim(['1.png', '2.png'], { reporters: ['flat', 'html'] })
.then(function (res) {
console.log(res);
})
.done();

// linting
imageOptim.lint(['1.png', '2.png'], {
tolerance: 0.08,
// tolerance: 20,
reporters: ['flat', 'html']
})
.then(function (res) {
console.log(res);
})
.done();
`

$3

`bash
$ imageoptim --help
Node.js wrapper for image compression algorithms

Usage:
imageoptim [OPTIONS] [ARGS]

Options:
-h, --help : Help
-v, --version : Shows the version number
-l, --lint : Lint mode
-t TOLERANCE, --tolerance=TOLERANCE : sets the measurement error in percentages or bytes (default: 0)
-r REPORTERS, --reporter=REPORTERS : flat or/and html (default: flat)

Arguments:
FILES : Paths to files (required)
`

REMARK! More information about options lint and tolerance can be found in the API.

#### Example

`bash
$ imageoptim path/to/file1 path/to/file2 --reporter=flat --reporter=html # optimization

$ imageoptim path/to/file --lint --tolerance=0.08 --reporter=flat --reporter=html # linting, tolerance is 8%

$ imageoptim path/to/file --lint --tolerance=20 # linting, tolerance is 20 bytes
``