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 the 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

Contribution

If you want to contribute, feel free to send a merge request or open a discussion. Currently, I just have time to maintain the package, but not enough to make big changes or add important features.

All contributions would be quite appreciated! 😉

Among changes I would like to apply: - Migrate to TypeScript - Transform to a functional component (that could help split the code)

• Make motion logic less dependent to React
• Replace Enzyme with another testing library

Breaking changes on v3

• The locked prop has been replaced by allowZoom and allowPan to handle zooming and panning events separately

Breaking changes on v2

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

Installation

Install the component

$ npm i -D react-prismazoom

Install the demo

This project includes a full-featured application demo.

First clone the project.

Go to the subfolder:

$ cd demo

Then, install it:

$ npm ci

Run the Webpack Dev Server:

$ npm start

Run unit tests

⚠️ There are no unit tests anymore since the previously used library is deprecated and doesn't support React 18. The current test suite needs to be adapted using a different library.

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).
allowZoom	boolean	true	Enable or disable zooming in place.
allowPan	boolean	true	Enable or disable panning in place.
allowTouchEvents	boolean	false	Enables touch event propagation.
allowParentPanning	boolean	false	When enabled, allows the parent element/page to pan with single-finger touch events as long as zoom = 1.
allowWheel	boolean	true	Enable or disable mouse wheel and touchpad zooming in place
ignoredMouseButtons	number[]	[]	Optional array of ignored mouse buttons allows to prevent panning for specific mouse buttons. By default all mouse buttons are enabled. MDN

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.