Awesome Open Source
Awesome Open Source

react-prismazoom

About

A pan and zoom component for React, using CSS transformations.

Depends only upon prop-types, react and react-dom modules.
Works on both desktop and mobile.

Online demo here!

Zoom features 🔎

  • Zoom with the mouse-wheel or a two-finger pinch
  • Zoom using double-click or double-tap
  • Zoom on selected area and center

Pan features 👆

  • Pan with the mouse pointer or with one finger when zoomed-in
  • Intuitive panning depending on available space when zoomed-in
  • Adjusts cursor style to indicate in which direction the element can be moved

Breaking changes on v2

  • The package now requires React v16.3 or higher (in order to use react references)
  • The zoom feature through gestures or mousewheel got some improvements to react better with all devices. You may need to adjust the scrollVelocity property passed to the component in order to keep the same effect.

Installation

Install the component

$ npm i -D react-prismazoom

Install the example project

This project includes a full-featured application example.

First clone the project.

Then, install it:

$ npm i

Run the Webpack Dev Server:

$ npm run start

Go to http://localhost:1664.

Note: sources of this example can be found in example/src.

Run unit tests

You can either run all tests at once:

$ npm test

Or run tests each time a change on source files occured:

$ npm run test:watch

Usage

Implementation

import PrismaZoom from 'react-prismazoom'

<PrismaZoom>
  <img src="my-image.png" />
  <p>A text that can be zoomed and dragged</p>
</PrismaZoom>

Props

Name Type Default Description
className string None Class name to apply on the zoom wrapper.
style object None Style to apply on the zoom wrapper. Note that transform, transition, cursor, touch-action and will-change cannot be overridden. Example: style={{backgroundColor: 'red'}}.
minZoom number 1 Minimum zoom ratio.
maxZoom number 5 Maximum zoom ratio.
scrollVelocity number 0.1 Zoom increment or decrement on each scroll wheel detection.
onZoomChange function null Function called each time the zoom value changes.
onPanChange function null Function called each time the posX or posY value changes (aka images was panned).
animDuration number 0.25 Animation duration (in seconds).
doubleTouchMaxDelay number 300 Max delay between two taps to consider a double tap (in milliseconds).
decelerationDuration number 750 Decelerating movement duration after a mouse up or a touch end event (in milliseconds).

Note: all props are optional.

Public methods

These functions can be called from parent components.

zoomIn (value)
Increments the zoom with the given value.
Param {value: Number} : Zoom value

zoomOut (value)
Decrements the zoom with the given value.
Param {value: Number} : Zoom value

zoomToZone (relX, relY, relWidth, relHeight)
Zoom-in on the specified zone with the given relative coordinates and dimensions.
Param {relX: Number} : Relative X position of the zone left-top corner in pixels
Param {relY: Number} : Relative Y position of the zone left-top corner in pixels
Param {relWidth: Number} : Zone width in pixels
Param {relHeight: Number} : Zone height in pixels

reset ()
Resets the component to its initial state.

getZoom ()
Returns the current zoom value.
Return {Number} : Zone value

License

React PrismaZoom is licensed under the ISC license. See the LICENSE.md file for more details.


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