README.md

react-pan-and-zoom-hoc

React HOC that helps with panning and zooming elements

Installation

Node

npm install --save react-pan-and-zoom-hoc

Browser

Include lib/panAndZoomHoc.js with RequireJS.

Building

git clone https://github.com/woutervh-/react-pan-and-zoom-hoc.git
npm install
npm run build

Running example locally

git clone https://github.com/woutervh-/react-pan-and-zoom-hoc.git
npm install
npm run build
npm run examples
# Now you can open http://localhost:8888/ to view the example.

Options

• x (number, default: 0.5): initial x-coordinate that represents the horizontal center of the viewport.
• y (number, default 0.5): initial y-coordinate that represents the vertical center of the viewport.
• scale (number, default 1): initial scale of the viewport.
• scaleFactor (number, default √2): when zooming in or out, use this factor to multiply the scale by.
• minScale (number, default: Number.EPSILON): minimal allowed value for the scale.
• maxScale (number, default: Number.POSITIVE_INFINITY): maximal allowed value for the scale.
• renderOnChange (boolean, default: false): if true, when panning or zooming, it will force a re-render of the component.
• passOnProps (boolean, default: false): if true, will pass on the x, y, and scale props to the wrapped component. If renderOnChange is also set to true this will cause the props (with updated values) to be passed on every time a pan or zoom event occurs.
• ignorePanOutside (boolean, default: false): if true, when the mouse exits the element the panning will stop. When the mouse re-enters the element, and the mouse button is still down, then panning will resume.
• disableScrollZoom (boolean, default: false): if true, the scroll wheel zooming functionality will be disabled.
• onPanStart (function): invoked when the component starts to pan. Receives the following arguments:
  • event (MouseEvent): original event which triggered the panning to start.
• onPanMove (function): invoked when the component pans in the x or y direction. Receives the following arguments:
  • x (number): new x-coordinate.
  • y (number): new y-coordinate.
  • event (MouseEvent): original event which triggered the panning movement.
• onPanEnd (function): invoked when the component stop panning. Receives the following arguments:
  • x (number): new x-coordinate.
  • y (number): new y-coordinate.
  • event (MouseEvent): original event which triggered the panning to stop.
• onZoom (function): currently not used, reserved for future use.
• onPanAndZoom (function): invoked when the component pans and zooms (for example when the mouse wheel is used). Receives the following arguments:
  • x (number): new x-coordinate.
  • y (number): new y-coordinate.
  • scale (number): new scale value.
  • event (MouseEvent): original event which triggered the pan/zoom event.

Unmanaged example

import React from 'react';
import panAndZoomHoc from 'react-pan-and-zoom-hoc';

class Figure extends React.Component {
    render() {
        const {x, y, scale, width, height, ...other} = this.props;
        return <div style={{width, height, overflow: 'hidden', border: '1px solid black'}}>
            <img style={{transform: `scale(${scale}, ${scale}) translate(${(0.5 - x) * width}px, ${(0.5 - y) * height}px`}} width={width} height={height} {...other}/>
        </div>;
    }
}

const PannableAndZoomableFigure = panAndZoomHoc(Figure);

class App extends React.Component {
    render() {
        return <PannableAndZoomableFigure
            renderOnChange={true}
            passOnProps={true}
            src="http://lorempixel.com/400/200/"
            width={400}
            height={200}
        />;
    }
}

Managed example

import React from 'react';
import panAndZoomHoc from '../src/panAndZoomHoc';

const InteractiveDiv = panAndZoomHoc('div');

class App extends React.Component {
    state = {
        x: 0.5,
        y: 0.5,
        scale: 1
    };

    handlePanAndZoom(x, y, scale) {
        this.setState({x, y, scale});
    }

    handlePanMove(x, y) {
        this.setState({x, y});
    }

    render() {
        const {x, y, scale} = this.state;

        return <InteractiveDiv
            x={x}
            y={y}
            scale={scale}
            scaleFactor={Math.sqrt(2)}
            minScale={1}
            maxScale={2 ** 18}
            onPanAndZoom={(x, y, scale) => this.handlePanAndZoom(x, y, scale)} style={{width: 250, height: 250, border: '1px solid black', position: 'relative'}}
            onPanMove={(x, y) => this.handlePanMove(x, y)}
        >
            <div style={{position: 'absolute', top: `${y * 100}%`, left: `${x * 100}%`, width: 1, height: 1, backgroundColor: 'black'}}/>
        </InteractiveDiv>;
    }
}