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A library for panning and zooming elements using CSS transforms 🔍 (REWRITE IN PROGRESS, see Projects ^)
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README.md

Panzoom

Build Status Greenkeeper badge

Examples

This rewrite is a work in progress and not yet published to npm

Have a look at the GitHub project to follow along on the status of this rewrite.


Panzoom is a small library (~3.5kb gzipped) to add panning and zooming functionality to an element. Rather than using absolute positioning or setting width and height, Panzoom uses CSS transforms to take advantage of hardware/GPU acceleration in the browser, which means the element can be anything: an image, a video, an iframe, a canvas, text, WHATEVER.

For common support questions, see the FAQ.

Browser support

Here is a list of currently supported browsers.

Mobile support

iOS, Android, and Windows Mobile are supported.

Panzoom includes support for touch gestures and even supports pinch gestures for zooming. It is perfectly suited for both mobile and desktop browsers. It uses pointer events by default wherever supported.

SVG support

Panzoom supports panning and zooming SVG elements directly.

In IE11, CSS animations/transitions do not work on SVG elements, at least for the transform style. They do work in other browsers.

One could implement transitions manually in IE11 using the setTransform option and integrating a tweening library for javascript animations (such as tween.js).

Installing

With npm:

$ npm install --save @panzoom/panzoom

With yarn:

$ yarn add @panzoom/panzoom

Panzoom uses UMD and can be loaded a lot of ways.

With ES6 imports:

import Panzoom from '@panzoom/panzoom'

With commonjs or browserify:

const Panzoom = require('@panzoom/panzoom')

With an AMD loader in an anonymous module:

define(['@panzoom/panzoom'], function(Panzoom) {
  Panzoom('.panzoom')
})

With a script tag:

<script src="/js/panzoom.js"></script>

Usage

const elem = document.getElementById('panzoom-element')
const panzoom = Panzoom(elem, {
  maxScale: 5
})
panzoom.pan(10, 10)
panzoom.zoom(2, { animate: true })

// Panning and pinch zooming are bound automatically (unless disablePan is true).
// There are several available methods for zooming
// that can be bound on button clicks or mousewheel.
button.addEventListener('click', panzoom.zoomIn)
elem.parentElement.addEventListener('wheel', panzoom.zoomWithWheel)

FAQ

1. What is transform-origin and why is it added to the panzoom element?

  • The transform-origin is the origin from which transforms are applied. Panzoom ensures the defaults are set to what it expects to calculate focal point zooming.
  • HTML elements default to '50% 50%'.
  • SVG elements default to '0 0'.

2. I am using Panzoom with an <object> tag and it's not working. What's wrong?

Object elements can eat up events, making it so they never reach Panzoom. To fix this, disable pointer events (pointer-events: none) on the <object> tag and call Panzoom using a wrapper.

3. My links aren't working! How do I enable an anchor within a panzoom element?

Add class options.excludeClass (default is "panzoom-exclude") to whatever element you want to be clickable. Panzoom will check for this class before handling the event. Alternatively, add a reference to the element to the exclude option, or call event.stopImmediatePropagation() in an event handler on the clickable element.

A note on the async nature of Panzoom

In some cases, setting one thing and then setting another synchronously will not work as intended.

For instance, the following usually works fine.

const panzoom = Panzoom(elem)
panzoom.zoom(2)
panzoom.pan(100, 100)

However, you might find that the things start breaking when the contain option is set.

This is due to the fact that in order for Panzoom to retrieve proper dimensions, the scale needs to be painted.

If you find that things aren't looking quite right, try the following instead...

panzoom.zoom(2)
setTimeout(() => panzoom.pan(100, 100))

Documentation

Panzoom(elem: HTMLElement | SVGElement, options?: Omit‹PanzoomOptions, "force"›): PanzoomObject

Defined in panzoom.ts:47

Parameters:

Name Type
elem HTMLElement | SVGElement
options? Omit‹PanzoomOptions, "force"›

Returns: PanzoomObject

PanzoomOptions

Includes MiscOptions, PanOptions, and ZoomOptions


MiscOptions

animate

animate? : boolean (Default: false)

Defined in types.ts:13

Whether to animate transitions


duration

duration? : number (Default: 200)

Defined in types.ts:15

Duration of the transition (ms)


easing

easing? : string (Default: "ease-in-out")

Defined in types.ts:17

CSS Easing used for transitions


exclude

exclude? : Element[]

Defined in types.ts:23

Add elements to this array that should be excluded from Panzoom handling. e.g. links and buttons that should not propagate the click event.


excludeClass

excludeClass? : string (Default: "panzoom-exclude")

Defined in types.ts:29

Add this class to any element within the Panzoom element that you want to exclude from Panzoom handling. e.g. links and buttons that should not propagate the click event.


force

force? : boolean

Defined in types.ts:45

force should be used sparingly to temporarily override and ignore options such as disablePan, disableZoom, and panOnlyWhenZoomed. This option cannot be passed to the Panzoom constructor or setOptions (to avoid setting this option globally).

// Overrides disablePan and panOnlyWhenZoomed
panzoom.pan(50, 100, { force: true })
// Overrides disableZoom
panzoom.zoom(1, { force: true })

handleStartEvent

handleStartEvent? : function

Defined in types.ts:69

On the first pointer event, when panning starts, the default Panzoom behavior is to call event.preventDefault() and event.stopPropagation() on that event. The former is almost certainly a necesity, the latter enables Panzoom elements within Panzoom elements.

But there are some cases where the default is not the desired behavior. Set this option to override that behavior.

// Only call preventDefault()
Panzoom(elem, {
  handleStartEvent: (event) => {
    event.preventDefault()
  }
})
// Do nothing (this probably breaks things on mobile tho)
Panzoom(elem, {
  handleStartEvent: () => {}
})

Type declaration:

▸ (event: Event): void

Parameters:

Name Type
event Event

origin

origin? : string

Defined in types.ts:83

Change this at your own risk. The transform-origin is the origin from which transforms are applied. Default: '50% 50%' for HTML and '0 0' for SVG. The defaults are set because changing the transform-origin on SVG elements doesn't work in IE.

Changing this should work with many things, but it will break focal point zooming, which assumes the defaults are set to do the more complicated calculations.

And again, changing this for SVG in IE doesn't work at all.


setTransform

setTransform? : setTransform

Defined in types.ts:101

Override the transform setter. This is exposed mostly so the user could set other parts of a transform aside from scale and translate. Default is defined in src/css.ts.

// This example always sets a rotation
// when setting the scale and translation
const panzoom = Panzoom(elem, {
  setTransform: (elem, { scale, x, y }) => {
    panzoom.setStyle('transform', `rotate(0.5turn) scale(${scale}) translate(${x}px, ${y}px)`)
  }
})

silent

silent? : boolean

Defined in types.ts:103

Silence all events


startScale

startScale? : number (Default: 1)

Defined in types.ts:109

Scale used to set the beginning transform


startX

startX? : number (Default: 0)

Defined in types.ts:105

X Value used to set the beginning transform


startY

startY? : number (Default: 0)

Defined in types.ts:107

Y Value used to set the beginning transform


PanOptions

Includes MiscOptions

contain

contain? : "inside" | "outside"

Defined in types.ts:126

Contain the panzoom element either inside or outside the parent. Inside: The panzoom element is smaller than its parent and cannot be panned to the outside. Outside: The panzoom element is larger than its parent and cannot be panned to the inside. In other words, no empty space around the element will be shown.


cursor

cursor? : string (Default: "move")

Defined in types.ts:128

The cursor style to set on the panzoom element


disablePan

disablePan? : boolean (Default: false)

Defined in types.ts:134

Disable panning functionality. Note: disablePan does not affect focal point zooming or the constrain option. The element will still pan accordingly.


disableXAxis

disableXAxis? : boolean (Default: false)

Defined in types.ts:136

Pan only on the Y axis


disableYAxis

disableYAxis? : boolean (Default: false)

Defined in types.ts:138

Pan only on the X axis


panOnlyWhenZoomed

panOnlyWhenZoomed? : boolean (Default: false)

Defined in types.ts:142

Disable panning while the scale is equal to the starting value


relative

relative? : boolean (Default: false)

Defined in types.ts:140

When passing x and y values to .pan(), treat the values as relative to their current values


ZoomOptions

Includes MiscOptions

disableZoom

disableZoom? : boolean (Default: false)

Defined in types.ts:147

Disable zooming functionality


focal

focal? : object

Defined in types.ts:154

Zoom to the given point on the panzoom element. This point is expected to be relative to the panzoom element's dimensions and is unrelated to the parent dimensions.

Type declaration:

  • x: number

  • y: number


maxScale

maxScale? : number (Default: 4)

Defined in types.ts:158

The maximum scale when zooming


minScale

minScale? : number (Default: 0.125)

Defined in types.ts:156

The minimum scale when zooming


step

step? : number (Default: 0.3)

Defined in types.ts:160

The step affects zoom calculation when zooming with a mouse wheel, when pinch zooming, or when using zoomIn/zoomOut


PanzoomObject

These methods are available after initializing Panzoom

destroy()

destroy: function

Defined in types.ts:175

Remove all event listeners bind to the the Panzoom element

Signature with return type:

▸ (): void


getOptions()

getOptions: function

Defined in types.ts:181

Returns a copy of the current options object

Signature with return type:

▸ (): PanzoomOptions


getPan()

getPan: function

Defined in types.ts:177

Get the current x/y translation

Signature with return type:

▸ (): object

  • x: number

  • y: number


getScale()

getScale: function

Defined in types.ts:179

Get the current scale

Signature with return type:

▸ (): number


pan()

pan: function

Defined in types.ts:192

Pan the Panzoom element to the given x and y coordinates

// Translates the element to 50px, 100px
panzoom.pan(50, 100)
// Pans the element right 10px and down 10px from its current position
panzoom.pan(10, 10, { relative: true })

Signature with return type:

▸ (x: number | string, y: number | string, panOptions?: PanOptions): CurrentValues

Parameters:

Name Type
x number | string
y number | string
panOptions? PanOptions

reset()

reset: function

Defined in types.ts:203

Reset the pan and zoom to startX, startY, and startScale. Animates by default, ignoring the global option. Pass { animate: false } to override.

panzoom.reset()
panzoom.reset({ animate: false })

Signature with return type:

▸ (resetOptions?: PanzoomOptions): CurrentValues

Parameters:

Name Type
resetOptions? PanzoomOptions

setOptions()

setOptions: function

Defined in types.ts:205

Change options for the Panzoom instance

Signature with return type:

▸ (options?: PanzoomOptions): void

Parameters:

Name Type
options? PanzoomOptions

setStyle()

setStyle: function

Defined in types.ts:207

A convenience method for setting prefixed styles on the Panzoom element

Signature with return type:

▸ (name: string, value: string): void

Parameters:

Name Type
name string
value string

zoom()

zoom: function

Defined in types.ts:216

Zoom the Panzoom element to the given scale

panzoom.zoom(2.2)
panzoom.zoom(2.2, { animate: true })

Signature with return type:

▸ (scale: number, zoomOptions?: ZoomOptions): CurrentValues

Parameters:

Name Type
scale number
zoomOptions? ZoomOptions

zoomIn()

zoomIn: function

Defined in types.ts:227

Zoom in using the predetermined increment set in options. Animates by default, ignoring the global option. Pass { animate: false } to override.

panzoom.zoomIn()
panzoom.zoomIn({ animate: false })

Signature with return type:

▸ (zoomOptions?: ZoomOptions): CurrentValues

Parameters:

Name Type
zoomOptions? ZoomOptions

zoomOut()

zoomOut: function

Defined in types.ts:238

Zoom out using the predetermined increment set in options. Animates by default, ignoring the global option. Pass { animate: false } to override.

panzoom.zoomOut()
panzoom.zoomOut({ animate: false })

Signature with return type:

▸ (zoomOptions?: ZoomOptions): CurrentValues

Parameters:

Name Type
zoomOptions? ZoomOptions

zoomToPoint()

zoomToPoint: function

Defined in types.ts:249

Zoom the Panzoom element to a focal point using the given pointer/touch/mouse event or constructed point. The clientX/clientY values should be calculated the same way as a pointermove event on the Panzoom element's parent.

panzoom.zoomToPoint(1.2, pointerEvent)

Signature with return type:

▸ (scale: number, point: object, zoomOptions?: ZoomOptions): CurrentValues

Parameters:

scale: number

point: object

Name Type
clientX number
clientY number

Optional zoomOptions: ZoomOptions


zoomWithWheel()

zoomWithWheel: function

Defined in types.ts:278

Zoom the Panzoom element to a focal point using the given WheelEvent

disablePan will prevent the focal point adjustment and will only zoom.

zoomWithWheel normally uses deltaY to determine the scale, but will fall back to deltaX in case the shift modifier is used with the wheel event. On a mac, that usually translates to horizontal scrolling, but this method assumes the desired behavior is zooming.

This is a convenience function that may not handle all use cases. Other cases should handroll solutions using the zoomToPoint method or the zoom method's focal option.

// Bind to mousewheel
elem.parentElement.addEventListener('wheel', panzoom.zoomWithWheel)
// Bind to shift+mousewheel
elem.parentElement.addEventListener('wheel', function(event) {
  if (!event.shiftKey) return
  panzoom.zoomWithWheel(event)
})

Signature with return type:

▸ (event: WheelEvent, zoomOptions?: ZoomOptions): CurrentValues

Parameters:

Name Type
event WheelEvent
zoomOptions? ZoomOptions

CurrentValues

scale

scale: number

Defined in types.ts:170


x

x: number

Defined in types.ts:168


y

y: number

Defined in types.ts:169

Events

The following events are available as custom events on the panzoom element using the native CustomEvent API. Add listeners the same way you would any other event.

elem.addEventListener('panzoomchange', (event) => {
  console.log(event.detail) // => { x: 0, y: 0, scale: 1 }
})

Notes about all events

  • The event object passed as an argument to the listener will always have a detail property with the current x, y, and scale values.
  • Events can be silenced when the silent option is set to true, either globally or when passed to pan, any zoom method, or reset.
  • Avoid putting too much logic in these event handlers as it could effect the performance of panning or zooming.

"panzoomstart"

Fired when the user starts a move or pinch zoom gesture on mobile.

"panzoomchange"

Fired whenever there is a pan, zoom, or reset. Note that direct calls to options.setTransform do not fire this event.

"panzoomzoom"

Fired whenever the zoom is changed by any Panzoom zoom method, directly or internally.

"panzoompan"

Fired whenever the zoom is changed by the pan method, directly or internally.

"panzoomend"

Fired when the user finishes a move or finishes a pinch zoom gesture on mobile.

"panzoomreset"

Fired whenever reset is called.

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