https://github.com/pontusab/react-native-image-manipulator

🗻Manipulate the image provided via uri. Available modifications are rotating, flipping (mirroring), resizing and cropping.
https://github.com/pontusab/react-native-image-manipulator

java objective-c react-native

Last synced: 2 months ago
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🗻Manipulate the image provided via uri. Available modifications are rotating, flipping (mirroring), resizing and cropping.

• Host: GitHub
• URL: https://github.com/pontusab/react-native-image-manipulator
• Owner: pontusab
• Created: 2018-09-25T20:12:57.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2023-01-04T07:23:44.000Z (about 2 years ago)
• Last Synced: 2024-09-24T14:05:05.624Z (4 months ago)
• Topics: java, objective-c, react-native
• Language: TypeScript
• Homepage:
• Size: 1.09 MB
• Stars: 21
• Watchers: 1
• Forks: 40
• Open Issues: 34
• Metadata Files:
  • Readme: README.md

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README

        
An API to modify images stored on the local file system.

## Installation

1. `yarn add https://github.com/pontusab/react-native-image-manipulator`

2. `pod 'react-native-image-manipulator', :path => './node_modules/react-native-image-manipulator/ios'`

3. `pod install`

## API

```js

import * as ImageManipulator from 'react-native-image-manipulator';

```

### `ImageManipulator.manipulateAsync(uri, actions, saveOptions)`

Manipulate the image provided via `uri`. Available modifications are rotating, flipping (mirroring), resizing and cropping. Each invocation results in a new file. With one invocation you can provide a set of actions to perform over the image. Overwriting the source file would not have an effect in displaying the result as images are cached.

#### Arguments

- **uri (_string_)** -- URI of the file to manipulate. Should be on the local file system.

- **actions (_array_)** --

  An array of objects representing manipulation options. Each object should have _only one_ of the following keys that corresponds to specific transformation:

  - **resize (_object_)** -- An object of shape `{ width, height }`. Values correspond to the result image dimensions. If you specify only one value, the other will be calculated automatically to preserve image ratio.

  - **rotate (_number_)** -- Degrees to rotate the image. Rotation is clockwise when the value is positive and counter-clockwise when negative.

  - **flip (_string_)** -- `ImageManipulator.FlipType.{Vertical, Horizontal}`. Only one flip per transformation is available. If you want to flip according to both axes then provide two separate transformations.

  - **crop (_object_)** -- An object of shape `{ originX, originY, width, height }`. Fields specify top-left corner and dimensions of a crop rectangle.

- **saveOptions (_object_)** -- A map defining how modified image should be saved:

  - **compress (_number_)** -- A value in range `0.0` - `1.0` specifying compression level of the result image. `1` means no compression (highest quality) and `0` the highest compression (lowest quality).

  - **format (_string_)** -- `ImageManipulator.SaveFormat.{JPEG, PNG}`. Specifies what type of compression should be used and what is the result file extension. `SaveFormat.PNG` compression is lossless but slower, `SaveFormat.JPEG` is faster but the image has visible artifacts. Defaults to `SaveFormat.JPEG`.

  - **base64 (_boolean_)** -- Whether to also include the image data in Base64 format.

#### Returns

Returns `{ uri, width, height }` where `uri` is a URI to the modified image (useable as the source for an `Image`/`Video` element), `width, height` specify the dimensions of the image. It can contain also `base64` - it is included if the `base64` saveOption was truthy, and is a string containing the JPEG/PNG (depending on `format`) data of the image in Base64--prepend that with `'data:image/xxx;base64,'` to get a data URI, which you can use as the source for an `Image` element for example (where `xxx` is 'jpeg' or 'png').

### Basic Example

This will first rotate the image 90 degrees clockwise, then flip the rotated image vertically and save it as a PNG.

```javascript

import React from 'react';

import { Button, View, Image } from 'react-native';

import { Asset } from 'expo-asset';

import * as ImageManipulator from 'react-native-image-manipulator';

export default class ImageManipulatorSample extends React.Component {

  state = {

    ready: false,

    image: null,

  };

  componentDidMount() {

    (async () => {

      const image = Asset.fromModule(require('./assets/snack-icon.png'));

      await image.downloadAsync();

      this.setState({

        ready: true,

        image,

      });

    })();

  }

  render() {

    return (

      

        {this.state.ready && this._renderImage()}

        

      

    );

  }

  _rotate90andFlip = async () => {

    const manipResult = await ImageManipulator.manipulateAsync(

      this.state.image.localUri || this.state.image.uri,

      [{ rotate: 90 }, { flip: ImageManipulator.FlipType.Vertical }],

      { compress: 1, format: ImageManipulator.SaveFormat.PNG }

    );

    this.setState({ image: manipResult });

  };

  _renderImage = () => {

    return (

      

        

      

    );

  };

}

```