react-native-pan-pinch-view

A view component for React Native with pinch to zoom and drag to pan functionality.

👋 Introduction

Even though the demo shows the library used with images, it was initially designed to show <View>s representing blueprints of rooms.

• Pinch to zoom with two fingers
• Drag one finger to pan
• Keep content inside container boundaries
• Configurable minimum and maximum scale
• Methods for programmatically updating position and scale

Thanks to react-native-reanimated all animations are running on the UI thread, so no fps drops are experienced.

AFAIK, Expo users should be able to use it once Expo updates toreact-native-gesture-handler@2.3.1.

If you want to zoom in on images exclusively, in a gallery-like UI, I recommend these packages, rather than my library:

• react-native-awesome-gallery
• react-native-image-zoom

👀 Prerequisites

This library uses react-native-reanimated v2 and the new API of react-native-gesture-handler.

Before installing it, you need to install those two libraries and set them up in your project:

• react-native-reanimated: Installation & Setup
• react-native-gesture-handler: Installation & Setup

⚙️ Installation

npm install react-native-pan-pinch-view

✂️ Usage

import PanPinchView from "react-native-pan-pinch-view";

// ...

const CONTAINER = {
  width: 300,
  height: 300,
};

const CONTENT = {
  width: 900,
  height: 400,
};
// ...

<PanPinchView
  minScale={1}
  initialScale={1}
  containerDimensions={{
    width: CONTAINER.width,
    height: CONTAINER.height,
  }}
  contentDimensions={{ width: CONTENT.width, height: CONTENT.height }}
>
  <Image
    style={[styles.image]}
    source={require('./assets/photo.jpg')}
  />
</PanPinchView>

// ...

const styles = StyleSheet.create({
  image: {
    width: CONTENT.width,
    height: CONTENT.height,
  },
});

⚪ Props

Property	Type	Default	Description
containerDimensions	Object	{width: number, height:number}	Width and height of the viewable area.
contentDimensions	Object	{width: number, height:number}	Width and height of the zoomable view.
minScale	Number?	0.5	Minimum value of scale.
maxScale	Number?	4	Maximum value of scale.
initialScale	Number?	1	Initial value of scale.

🛠 Methods

Method	Params	Return	Description
scaleTo	value: number, animated: boolean	void	Sets sharedValue scale to value, if animated is true uses withTiming
setContentSize	width: number, height: number	void	Updates sharedValue contentSize and overrides prop: contentDimensions
translateTo	x: number, y: number, animated: boolean	void	Updates content translateX / translateY, if animated is true uses withTiming
setMinScale	value: number	void	Updates minScale value
setMaxScale	value: number	void	Updates maxScale value
getScale		number	Returns current value of sharedValue scale

You can also refer to the app inside example/ for a running demo of this library.

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT