https://github.com/shawnbot/node-cops

An image manipulation tool belt for Node.js
https://github.com/shawnbot/node-cops

Last synced: about 2 months ago
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An image manipulation tool belt for Node.js

• Host: GitHub
• URL: https://github.com/shawnbot/node-cops
• Owner: shawnbot
• Created: 2014-07-17T20:35:08.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2014-07-20T00:14:39.000Z (over 10 years ago)
• Last Synced: 2024-11-02T04:08:04.689Z (2 months ago)
• Language: JavaScript
• Homepage:
• Size: 715 KB
• Stars: 4
• Watchers: 2
• Forks: 0
• Open Issues: 7
• Metadata Files:
  • Readme: README.md

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README

        
# node-cops

> ![](https://raw.githubusercontent.com/shawnbot/node-cops/master/assets/node-cops.jpg)

>

> Original photo by [Quinn Dombrowski](https://www.flickr.com/photos/quinnanya/6668359047/). Sorry.

Cops is an image manipulation tool belt for Node.js using a

[Cairo](http://cairographics.org/)-backed

[Canvas implementation](https://github.com/Automattic/node-canvas). The goal is

to make common image operations such as resizing, compositing, cropping, and creating

text overlays as simple and friendly as possible.

**A note on performance:** I've made every attempt to keep I/O buffered and

asynchronous whenever possible, but because node-canvas currently provides

[no good way to create an Image from a Buffer](https://github.com/Automattic/node-canvas/issues/413),

*reading images blocks the thread*. You will probably experience hiccups when loading

large images.

## Installation

Install cops with [npm](http://npmjs.org):

```sh

$ npm install cops

```

## Usage

The `cops` module exposes both classes and asynchronous

helpers for specific tasks. Check out the examples below, or refer to the [API documentation](https://github.com/shawnbot/node-cops/wiki/API) for more info.

### Resize an image

```js

var cops = require("cops"),

    shrink = cops.resize("50%");

cops.read("big.png", function(error, canvas) {

  shrink(canvas, function(error, canvas) {

    cops.write("small.png", canvas, function(error) {

      // we're done here

    });

  });

});

```

Cops operations are designed to work with

[async.waterfall](https://github.com/caolan/async#waterfall),

each producing a Canvas instance for the next operation:

```js

var cops = require("cops"),

    async = require("async");

async.waterfall([

  cops.read("big.png"),

  cops.resize({width: 200, height: 200}),

  cops.write("small.png")

], function(error, canvas) {

  // mic drop

});

```

## Command Line Utility

The `cops` CLI gives you some nice, node-y tools:

```sh

# resize images

$ cops resize big.jpg 50% small.jpg

$ cat big.jpg | cops resize - 50% > small.jpg

# compose images

$ cops compose --gravity southeast photo.jpg watermark.png

```

Run `cops --help` for more information.