# @google-cloud/vision ([Alpha][versioning])
> Google Cloud Vision Client Library for Node.js

*Looking for more Google APIs than just Vision? You might want to check out [`google-cloud`][google-cloud].*

- [API Documentation][gcloud-vision-docs]
- [Official Documentation][cloud-vision-docs]


```sh
$ npm install --save @google-cloud/vision
```
```js
var vision = require('@google-cloud/vision')({
  projectId: 'grape-spaceship-123',
  keyFilename: '/path/to/keyfile.json'
});

// Read the text from an image.
vision.detectText('./image.jpg', function(err, text) {
  // text = [
  //   'This was text found in the image',
  //   'This was more text found in the image'
  // ]
});

// Detect faces and the locations of their features in an image.
vision.detectFaces('./image.jpg', function(err, faces) {
  // faces = [
  //   {
  //     angles: {pan,tilt,roll},
  //     bounds: {
  //       head: [{x,y},{x,y},{x,y},{x,y}],
  //       face: [{x,y},{x,y},{x,y},{x,y}]
  //     },
  //     features: {
  //       confidence: 34.489909,
  //       chin: {
  //         center: {x,y,z},
  //         left: {x,y,z},
  //         right: {x,y,z}
  //       },
  //       ears: {
  //         left: {x,y,z},
  //         right: {x,y,z}
  //       },
  //       eyebrows: {
  //         left: {
  //           left: {x,y,z},
  //           right: {x,y,z},
  //           top: {x,y,z}
  //         },
  //         right: {
  //           left: {x,y,z},
  //           right: {x,y,z},
  //           top: {x,y,z}
  //         }
  //       },
  //       eyes: {
  //         left: {
  //           bottom: {x,y,z},
  //           center: {x,y,z},
  //           left: {x,y,z},
  //           pupil: {x,y,z},
  //           right: {x,y,z},
  //           top: {x,y,z}
  //         },
  //         right: {
  //           bottom: {x,y,z},
  //           center: {x,y,z},
  //           left: {x,y,z},
  //           pupil: {x,y,z},
  //           right: {x,y,z},
  //           top: {x,y,z}
  //         }
  //       },
  //       forehead: {x,y,z},
  //       lips: {
  //         bottom: {x,y,z},
  //         top: {x,y,z}
  //       },
  //       mouth: {
  //         center: {x,y,z},
  //         left: {x,y,z},
  //         right: {x,y,z}
  //       },
  //       nose: {
  //         bottom: {
  //           center: {x,y,z},
  //           left: {x,y,z},
  //           right: {x,y,z}
  //         },
  //         tip: {x,y,z},
  //         top: {x,y,z}
  //       }
  //     },
  //     confidence: 56.748849,
  //     blurry: false,
  //     dark: false,
  //     happy: false,
  //     hat: false,
  //     mad: false,
  //     sad: false,
  //     surprised: false
  //   }
  // ]
});

// Promises are also supported by omitting callbacks.
vision.detectFaces('./image.jpg').then(function(data) {
  var faces = data[0];
});

// It's also possible to integrate with third-party Promise libraries.
var vision = require('@google-cloud/vision')({
  promise: require('bluebird')
});
```


## Authentication

It's incredibly easy to get authenticated and start using Google's APIs. You can set your credentials on a global basis as well as on a per-API basis. See each individual API section below to see how you can auth on a per-API-basis. This is useful if you want to use different accounts for different Google Cloud services.

### On Google Cloud Platform

If you are running this client on Google Cloud Platform, we handle authentication for you with no configuration. You just need to make sure that when you [set up the GCE instance][gce-how-to], you add the correct scopes for the APIs you want to access.

``` js
var vision = require('@google-cloud/vision')();
// ...you're good to go!
```

### Elsewhere

If you are not running this client on Google Cloud Platform, you need a Google Developers service account. To create a service account:

1. Visit the [Google Developers Console][dev-console].
2. Create a new project or click on an existing project.
3. Navigate to  **APIs & auth** > **APIs section** and turn on the following APIs (you may need to enable billing in order to use these services):
  * Google Cloud Vision API
4. Navigate to **APIs & auth** >  **Credentials** and then:
  * If you want to use a new service account, click on **Create new Client ID** and select **Service account**. After the account is created, you will be prompted to download the JSON key file that the library uses to authenticate your requests.
  * If you want to generate a new key for an existing service account, click on **Generate new JSON key** and download the JSON key file.

``` js
var projectId = process.env.GCLOUD_PROJECT; // E.g. 'grape-spaceship-123'

var vision = require('@google-cloud/vision')({
  projectId: projectId,

  // The path to your key file:
  keyFilename: '/path/to/keyfile.json'

  // Or the contents of the key file:
  credentials: require('./path/to/keyfile.json')
});

// ...you're good to go!
```


[versioning]: https://github.com/GoogleCloudPlatform/google-cloud-node#versioning
[google-cloud]: https://github.com/GoogleCloudPlatform/google-cloud-node/
[gce-how-to]: https://cloud.google.com/compute/docs/authentication#using
[dev-console]: https://console.developers.google.com/project
[gcloud-vision-docs]: https://googlecloudplatform.github.io/google-cloud-node/#/docs/vision
[cloud-vision-docs]: https://cloud.google.com/vision/docs