react-native-linear-gradient


A component for react-native, as seen in
react-native-login.

Table of Contents

- Installation
- Usage and Examples
- Props
- Example App
- Troubleshooting
- Other Platforms

Installation

Using Yarn

``sh
yarn add react-native-linear-gradient
`

Using npm

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

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Run npx pod-install

Linking (for React Native <= 0.59 only)

Note: If you are using react-native version 0.60 or higher you don't need to link react-native-linear-gradient.

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`sh
react-native link react-native-linear-gradient
`

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Examples

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The following code will produce something like this:

!Example code result

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

// Within your render function


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// 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',
},
});
`

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Using the styles from above, set start and end like this to make the gradient go from left to right, instead of from top to bottom:

`javascript


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`

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On iOS you can use the MaskedViewIOS to display text with a gradient. The trick here is to render the text twice; once for the mask, and once to let the gradient have the correct size (hence the opacity: 0):

`jsx
}>




`

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Check out Examples/AnimatedGradient (git clone this project, cd into it, npm install, open in Xcode and run) to see how this is done:

!Example with extra props

This gif was created using licecap - a great piece of free OSS

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The use of transparent color will most likely not lead to the expected result. transparent is actually a transparent black color (rgba(0, 0, 0, 0)). If you need a gradient in which the color is "fading", you need to have the same color with changing alpha channel. Example:

`jsx
// RGBA

// Hex


`

Props

In addition to regular View props, you can also provide additional props to customize your gradient look:

#### colors

An array of at least two color values that represent gradient colors. Example: ['red', 'blue'] sets gradient from red to blue.

#### start

An optional object of the following type: { x: number, y: number }. Coordinates declare the position that the gradient starts at, as a fraction of the overall size of the gradient, starting from the top left corner. Example: { x: 0.1, y: 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 optional array of numbers defining the location of each gradient color stop, mapping to the color with the same index in colors prop. Example: [0.1, 0.75, 1] means that first color will take 0% - 10%, second color will take 10% - 75% and finally third color will occupy 75% - 100%.

`javascript
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}>

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`

!Example with extra props

#### useAngle / angle / angleCenter

You may want to achieve an angled gradient effect, similar to those in image editors like Photoshop.
One issue is that you have to calculate the angle based on the view's size, which only happens asynchronously and will cause unwanted flickr.

In order to do that correctly you can set { useAngle: true, angle: 45, angleCenter: { x: 0.5, y: 0.5} }, to achieve a gradient with a 45 degrees angle, with its center positioned in the view's exact center.

useAngle is used to turn on/off angle based calculation (as opposed to start/end).
angle is the angle in degrees.
angleCenter is the center point of the angle (will control the weight and stretch of the gradient like it does in photoshop.

An example app

You can see this component in action in brentvatne/react-native-login.

Troubleshooting

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1. Ensure you have followed the installations steps correctly. (react-native link for React Native < 0.60 and npx pod-install instead for > 0.60).
2. Ensure pod 'BVLinearGradient', :path => '../node_modules/react-native-linear-gradient' is present in your ios/Podfile
3. Ensure you use ios/.xcworkspace file instead of ios./.xcodeproj

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Ensure you import the LinearGradient correctly:

`javascript
// Like that:
import LinearGradient from 'react-native-linear-gradient'

// Not like that:
import { LinearGradient } from 'react-native-linear-gradient'
`

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Clearing build caches and reinstalling dependencies sometimes solve some issues. Try next steps:

1. Reinstalling node_modules with rm -rf node_modules && yarn
2. Clearing Android Gradle cache with (cd android && ./gradlew clean)
3. Reinstalling iOS CocoaPods with (cd ios && rm -rf ./ios/Pods/**) && npx pod-install`
4. Clearing Xcode Build cache (open Xcode and go to Product -> Clean Build Folder)

For other troubleshooting issues, go to React Native Troubleshooting

Other platforms

- Web: react-native-web-community/react-native-web-linear-gradient

License

MIT