react-native-linear-gradient/README.md

# react-native-linear-gradient

A `<LinearGradient>` component for react-native, as seen in
[react-native-login](https://github.com/brentvatne/react-native-login).

Version 2.0 supports react-native >= 0.40.0

## Add it to your project

You can try linking the project automatically:

`$ react-native link`

or do it manually as described below:

### iOS

- Run `npm install react-native-linear-gradient --save`

Then either:

##### Cocoapods
add the following line to your Podfile:

```sh
pod 'React', :path => '../node_modules/react-native'
pod 'BVLinearGradient', :path => '../node_modules/react-native-linear-gradient'
```

or:

##### Manually

1. Open your project in XCode, right click on `Libraries` and click `Add
   Files to "Your Project Name"` Look under `node_modules/react-native-linear-gradient` and add `BVLinearGradient.xcodeproj`.  [(Screenshot)](http://url.brentvatne.ca/g9Wp).
2. Add `libBVLinearGradient.a` to `Build Phases -> Link Binary With Libraries`
   [(Screenshot)](http://url.brentvatne.ca/g9Wp).
3. Click on `BVLinearGradient.xcodeproj` in `Libraries` and go the `Build
   Settings` tab. Double click the text to the right of `Header Search
   Paths` and verify that it has `$(SRCROOT)/../react-native/React` - if it
   isn't, then add it. This is so XCode is able to find the headers that
   the `BVLinearGradient` source files are referring to by pointing to the
   header files installed within the `react-native` `node_modules`
   directory. [(Screenshot)](http://url.brentvatne.ca/7wE0).

Then:


- Whenever you want to use it within React code now you can: `import LinearGradient from 'react-native-linear-gradient';`


**If you're having trouble, you can point your `package.json` at github to see if the issue has been fixed.  Simply change the dependency**

`"react-native-linear-gradient": "react-native-community/react-native-linear-gradient",`

**to get the data right from github instead of npm and then `npm install`**

For instance the podspec file does not contain the right data (author attributes etc..) in npm while it does in the github repo.

#### Android

1. in `android/settings.gradle`
```
...
include ':react-native-linear-gradient'
project(':react-native-linear-gradient').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-linear-gradient/android')
```

2. in `android/app/build.gradle` add:
```
dependencies {
    ...
    compile project(':react-native-linear-gradient')
}
```

3. and finally, in `android/src/main/java/com/{YOUR_APP_NAME}/MainActivity.java` for react-native < 0.29,
   or `android/src/main/java/com/{YOUR_APP_NAME}/MainApplication.java` for react-native >= 0.29 add:
```java
//...
import com.BV.LinearGradient.LinearGradientPackage; // <--- This!
//...
@Override
protected List<ReactPackage> getPackages() {
  return Arrays.<ReactPackage>asList(
    new MainReactPackage(),
    new LinearGradientPackage() // <---- and This!
  );
}
```

## Examples

### Simple

The following code will produce something like this:

![Example code result](https://raw.githubusercontent.com/react-native-community/react-native-linear-gradient/master/images/example.png)

```javascript
import LinearGradient from 'react-native-linear-gradient';

// Within your render function
<LinearGradient colors={['#4c669f', '#3b5998', '#192f6a']} style={styles.linearGradient}>
  <Text style={styles.buttonText}>
    Sign in with Facebook
  </Text>
</LinearGradient>

// Later on in your styles..
var styles = StyleSheet.create({
  linearGradient: {
    flex: 1,
    paddingLeft: 15,
    paddingRight: 15,
    borderRadius: 5
  },
  buttonText: {
    fontSize: 18,
    fontFamily: 'Gill Sans',
    textAlign: 'center',
    margin: 10,
    color: '#ffffff',
    backgroundColor: 'transparent',
  },
});
```

### Additional props
You can also use start and end points, as well as specify the locations
for the gradient color changes with the `start`, `end`, `colors` and `locations`
props:
#### colors
An array of colors that represent stops in the gradient. At least two colors are required (otherwise it's not a gradient, it's just a fill!).
  
#### start
An array of [x, y] where x and y are floats. They represent the position that the gradient starts at, as a fraction of the overall size of the gradient. For example, [0.1, 0.1] means that the gradient will start 10% from the top and 10% from the left.
 
#### end
Same as start but for the end of the gradient.
 
#### locations
An array of the same lenth as colors, where each element is a float with the same meaning as the start and end values, but instead they indicate where the color at that index should be.



```javascript
<LinearGradient
  start={{x: 0.0, y: 0.25}} end={{x: 0.5, y: 1.0}}
  locations={[0,0.5,0.6]}
  colors={['#4c669f', '#3b5998', '#192f6a']}
  style={styles.linearGradient}>
  <Text style={styles.buttonText}>
    Sign in with Facebook
  </Text>
</LinearGradient>
```

![Example with extra props](https://raw.githubusercontent.com/react-native-community/react-native-linear-gradient/master/images/example-other-props.png)

### Updating the values for fun

Check out [Examples/AnimatedGradient](https://github.com/react-native-community/react-native-linear-gradient/blob/master/Examples/AnimatedGradient/src/index.js) (`git clone` this project, cd into it, npm install, open in XCode and run) to see how this is done:

![Example with extra props](https://raw.githubusercontent.com/react-native-community/react-native-linear-gradient/master/images/example-animated.gif)

*This gif was created using [licecap](http://www.cockos.com/licecap/) - a great piece of free OSS*

### An example app
You can see this component in action in [brentvatne/react-native-login](https://github.com/brentvatne/react-native-login/blob/master/App/Screens/LoginScreen.js#L58-L62).

### License

License is MIT