node-pngquant-native

A pngquant addon of node

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node-pngquant-native
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Readme

node-pngquant-native

NPM version
node-pngquant-native is an addon of node, support node version v0.8.0 to latest, It compress a buffer of .png image, so can't call other processes.

install

npm install -g node-pngquant-native

make

if install fail for you. download the source install it.
  1. clone source code
```bash
$ git clone https://github.com/xiangshouding/node-pngquant-native.git
```
  1. invoke npm install -g .
```bash
$ cd node-pngquant-native
$ npm install -g .
```

require

use

var pngquant = require('node-pngquant-native');

fs.readFile('./alphatest.png', function (err, buffer) {
  if (err) throw err;
  var resBuffer = pngquant.compress(buffer, {
    "speed": 1 //1 ~ 11
  });

  fs.writeFile('./alphatest_out.png', resBuffer, {
      flags: 'wb'
  }, function(err){});
});

Api

pngquant.compress(buffer, option)

var pngquant = require('node-pngquant-native')
var option = {
    speed: 11
    //...    
}

var resBuffer = pngquant.compress(buffer, option);

option

  • option.speed
Speed/quality trade-off from 1 (brute-force) to 11 (fastest). The default is 3. Speed 10 has 5% lower quality, but is 8 times faster than the default. Speed 11 disables dithering and lowers compression level.

```javascript
var opt = {
    speed: 11
}
```
  • option.quality = [min, max]
min and max are numbers in range 0 (worst) to 100 (perfect), similar to JPEG. pngquant will use the least amount of colors required to meet or exceed the max quality. If conversion results in quality below the min quality the image won't be saved (if outputting to stdin, 24-bit original will be output) and pngquant will exit with status code 99.

```javascript
var opt = {
    quality: [40, 60]
}
```
  • option.iebug

Workaround for IE6, which only displays fully opaque pixels. pngquant will make almost-opaque pixels fully opaque and will avoid creating new transparent colors.

```javascript
var opt = {
    iebug: true
}
```

ChangeLog

1.0.5

  • support node 8.x on MacOS