README

Examples

Panzoom is a small library (~3.7kb 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) {
  const elem = document.getElementById('panzoom-element')
  Panzoom(elem)
})

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:58

Parameters:

Returns: PanzoomObject

PanzoomOptions

Includes MiscOptions, PanOptions, and ZoomOptions

MiscOptions

animate

• Optional animate: boolean (Default: false)

Defined in types.ts:21

Whether to animate transitions

canvas

• Optional canvas: boolean (Default: false)

Defined in types.ts:32

This option treats the Panzoom element's parent as a canvas. Effectively, Panzoom binds the down handler to the parent instead of the Panzoom element, so that pointer events anywhere on the "canvas" moves its children. See issue #472.

Note: setting this option to true also changes where the cursor style is applied (i.e. the parent).

duration

• Optional duration: number (Default: 200)

Defined in types.ts:34

Duration of the transition (ms)

easing

• Optional easing: string (Default: "ease-in-out")

Defined in types.ts:36

CSS Easing used for transitions

exclude

• Optional exclude: Element[] (Default: [])

Defined in types.ts:43

Add elements to this array that should be excluded from Panzoom handling. Ancestors of event targets are also checked. e.g. links and buttons that should not propagate the click event.

excludeClass

• Optional excludeClass: string (Default: "panzoom-exclude")

Defined in types.ts:50

Add this class to any element within the Panzoom element that you want to exclude from Panzoom handling. That element's children will also be excluded. e.g. links and buttons that should not propagate the click event.

force

• Optional force: boolean

Defined in types.ts:66

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

• Optional handleStartEvent: (event: Event) => void (Default: (e: Event) => void)

Defined in types.ts:91

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 necessity; 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 can change dragging behavior on mobile.
Panzoom(elem, {
  handleStartEvent: () => {}
})

noBind

• Optional noBind: boolean

Defined in types.ts:95

Skip binding the default Panzoom event listeners

origin

• Optional origin: string

Defined in types.ts:109

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.

overflow

• Optional overflow: string (Default: "hidden")

Defined in types.ts:111

The overflow CSS value for the parent. Defaults to 'hidden'

setTransform

• Optional setTransform: typeof setTransform (Default: setTransform)

Defined in types.ts:129

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

• Optional silent: boolean

Defined in types.ts:131

Silence all events

startScale

• Optional startScale: number (Default: 1)

Defined in types.ts:137

Scale used to set the beginning transform

startX

• Optional startX: number (Default: 0)

Defined in types.ts:133

X Value used to set the beginning transform

startY

• Optional startY: number (Default: 0)

Defined in types.ts:135

Y Value used to set the beginning transform

touchAction

• Optional touchAction: string (Default: "none")

Defined in types.ts:147

This value is used to set touch-action on both the Panzoom element and its parent. It is needed because that the native scroll on mobile interferes with panning and pinch zooming. Set this to empty string to re-enable scrolling on mobile, but note that both scrolling and panning cannot work at the same time.

PanOptions

Includes MiscOptions

contain

• Optional contain: "inside" | "outside"

Defined in types.ts:166

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.

Note: the containment pan adjustment is not affected by the disablePan option.

cursor

• Optional cursor: string (Default: "move")

Defined in types.ts:168

The cursor style to set on the panzoom element

disablePan

• Optional disablePan: boolean (Default: false)

Defined in types.ts:174

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

disableXAxis

• Optional disableXAxis: boolean (Default: false)

Defined in types.ts:176

Pan only on the Y axis

disableYAxis

• Optional disableYAxis: boolean (Default: false)

Defined in types.ts:178

Pan only on the X axis

panOnlyWhenZoomed

• Optional panOnlyWhenZoomed: boolean (Default: false)

Defined in types.ts:182

Disable panning while the scale is equal to the starting value

relative

• Optional relative: boolean (Default: false)

Defined in types.ts:180

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

ZoomOptions

Includes MiscOptions

disableZoom

• Optional disableZoom: boolean (Default: false)

Defined in types.ts:187

Disable zooming functionality

focal

• Optional focal: { x: number ; y: number }

Defined in types.ts:194

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:

maxScale

• Optional maxScale: number (Default: 4)

Defined in types.ts:198

The maximum scale when zooming

minScale

• Optional minScale: number (Default: 0.125)

Defined in types.ts:196

The minimum scale when zooming

step

• Optional step: number (Default: 0.3)

Defined in types.ts:200

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

bind()

• bind: () => void

Defined in types.ts:221

Bind the default down, move, and up event listeners to the Panzoom element. This does not normally need to be called. It gets called by default when creating a new Panzoom object, but can be skipped with the noBind option.

destroy()

• destroy: () => void

Defined in types.ts:223

Remove all event listeners bound to the the Panzoom element

eventNames()

• eventNames: { down: string ; move: string ; up: string }

Defined in types.ts:229

This object exposes the event names used by Panzoom, depending on the current browser's support for Pointer or Touch events.

Signature with return type:

getOptions()

• getOptions: () => PanzoomOptions

Defined in types.ts:235

Returns a copy of the current options object

getPan()

• getPan: () => { x: number ; y: number }

Defined in types.ts:231

Get the current x/y translation

getScale()

• getScale: () => number

Defined in types.ts:233

Get the current scale

pan()

• pan: (x: number | string, y: number | string, panOptions?: PanOptions](../modules/types.md#panoptions)) => [CurrentValues

Defined in types.ts:246

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 })

reset()

• reset: (resetOptions?: PanzoomOptions](../modules/types.md#panzoomoptions)) => [CurrentValues

Defined in types.ts:259

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

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

setOptions()

• setOptions: (options?: PanzoomOptions) => void

Defined in types.ts:261

Change options for the Panzoom instance

setStyle()

• setStyle: (name: string, value: string) => void

Defined in types.ts:263

A convenience method for setting prefixed styles on the Panzoom element

zoom()

• zoom: (scale: number, zoomOptions?: ZoomOptions](../modules/types.md#zoomoptions)) => [CurrentValues

Defined in types.ts:272

Zoom the Panzoom element to the given scale

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

zoomIn()

• zoomIn: (zoomOptions?: ZoomOptions](../modules/types.md#zoomoptions)) => [CurrentValues

Defined in types.ts:283

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 })

zoomOut()

• zoomOut: (zoomOptions?: ZoomOptions](../modules/types.md#zoomoptions)) => [CurrentValues

Defined in types.ts:294

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 })

zoomToPoint()

• zoomToPoint: (scale: number, point: { clientX: number ; clientY: number }, zoomOptions?: ZoomOptions](../modules/types.md#zoomoptions)) => [CurrentValues

Defined in types.ts:305

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)

zoomWithWheel()

• zoomWithWheel: (event: WheelEvent, zoomOptions?: ZoomOptions](../modules/types.md#zoomoptions)) => [CurrentValues

Defined in types.ts:334

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

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.

Note: the focal point zooming pan adjustment is not affected by the disablePan 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 will automatically use `deltaX` here instead
  // of `deltaY`. On a mac, the shift modifier usually
  // translates to horizontal scrolling, but Panzoom assumes
  // the desired behavior is zooming.
  panzoom.zoomWithWheel(event)
})

CurrentValues

isSVG

• Optional isSVG: boolean

Defined in types.ts:211

scale

• scale: number

Defined in types.ts:210

x

• x: number

Defined in types.ts:208

y

• y: number

Defined in types.ts:209

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 object with the following properties:
  • The current x value
  • The current y value
  • The current scale
  • An originalEvent property with the original event that triggered the panzoom event, if applicable. For example, the originalEvent property for a panzoomstart event would be either a pointerdown, touchstart, or mousedown event.
• 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 pan 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.