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README.md

Panzoom

Build Status

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>

With a script tag from a CDN:

<script src="https://unpkg.com/@panzoom/panzoom@4.4.4/dist/panzoom.min.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))

4. I'm using Panzoom with SVG text elements and am seeing some weird text resizing. How do I fix this?

Add text-rendering="geometricPrecision" to your <text> elements.

<text text-rendering="geometricPrecision" x="40" y="120">Hello World</text>

5. I'm using Panzoom on a canvas element that renders a PDF. How do I avoid the PDF getting blurry when scaled?

See this stackoverflow question


Documentation

Panzoom

Panzoom(elem, options?): [PanzoomObject](#PanzoomObject)

Parameters

Name Type
elem HTMLElement | SVGElement
options? Omit<[PanzoomOptions](#PanzoomOptions), "force">

Returns

[PanzoomObject](#PanzoomObject)

Defined in

panzoom.ts:59

PanzoomOptions

Includes MiscOptions, PanOptions, and ZoomOptions

MiscOptions

These options can be passed to Panzoom(), as well as any pan or zoom function. One exception is force, which can only be passed to methods like pan() or zoom(), but not Panzoom() or setOptions() as it should not be set globally.

animate

Optional animate: boolean (Default: false)

Whether to animate transitions

Defined in

types.ts:21

canvas

Optional canvas: boolean (Default: false)

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).

Defined in

types.ts:32

duration

Optional duration: number (Default: 200)

Duration of the transition (ms)

Defined in

types.ts:34

easing

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

CSS Easing used for transitions

Defined in

types.ts:36

exclude

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

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.

Defined in

types.ts:43

excludeClass

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

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.

Defined in

types.ts:50

force

Optional force: boolean

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 })

Defined in

types.ts:66

noBind

Optional noBind: boolean

Skip binding the default Panzoom event listeners

Defined in

types.ts:95

origin

Optional origin: string

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.

Defined in

types.ts:109

overflow

Optional overflow: string (Default: "hidden")

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

Defined in

types.ts:111

pinchAndPan

Optional pinchAndPan: boolean (Default: false)

Set to true to enable panning during pinch zoom. Note: this is zooming to a point and panning in the same frame. In other words, the zoom has not yet painted and therefore the pan is working with old dimensions. Essentially, it may be best to avoid using this option when using contain.

Related issues: #512 #606

Defined in

types.ts:124

setTransform

Optional setTransform: (elem: HTMLElement | SVGElement, __namedParameters: CurrentValues, _options?: PanzoomOptions) => void

Set the transform using the proper prefix

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)`)
  }
})
Parameters
Name Type
elem HTMLElement | SVGElement
__namedParameters CurrentValues
_options? PanzoomOptions
Returns

void

Defined in

types.ts:128

silent

Optional silent: boolean

Silence all events

Defined in

types.ts:130

startScale

Optional startScale: number (Default: 1)

Scale used to set the beginning transform

Defined in

types.ts:136

startX

Optional startX: number (Default: 0)

X Value used to set the beginning transform

Defined in

types.ts:132

startY

Optional startY: number (Default: 0)

Y Value used to set the beginning transform

Defined in

types.ts:134

touchAction

Optional touchAction: string (Default: "none")

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.

Defined in

types.ts:146

Methods

handleStartEvent

Optional handleStartEvent(event): void

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: () => {}
})

Parameters

Name Type
event Event

Returns

void

Defined in

types.ts:91

PanOptions (includes MiscOptions)

contain

Optional contain: "inside" | "outside"

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.

Defined in

types.ts:165

cursor

Optional cursor: string (Default: "move")

The cursor style to set on the panzoom element

Defined in

types.ts:167

disablePan

Optional disablePan: boolean (Default: false)

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

Defined in

types.ts:173

disableXAxis

Optional disableXAxis: boolean (Default: false)

Pan only on the Y axis

Defined in

types.ts:175

disableYAxis

Optional disableYAxis: boolean (Default: false)

Pan only on the X axis

Defined in

types.ts:177

panOnlyWhenZoomed

Optional panOnlyWhenZoomed: boolean (Default: false)

Disable panning while the scale is equal to the starting value

Defined in

types.ts:181

relative

Optional relative: boolean (Default: false)

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

Defined in

types.ts:179

roundPixels

Optional roundPixels: boolean

Round x and y values to whole numbers. This can help prevent images and text from looking blurry, but the higher the scale, the more it becomes necessary to use fractional pixels. Use your own judgment on how much to limit zooming in when using this option.

Defined in

types.ts:190

ZoomOptions (includes MiscOptions)

disableZoom

Optional disableZoom: boolean (Default: false)

Disable zooming functionality

Defined in

types.ts:195

focal

Optional focal: Object

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

Name Type
x number
y number

Defined in

types.ts:202

maxScale

Optional maxScale: number (Default: 4)

The maximum scale when zooming

Defined in

types.ts:206

minScale

Optional minScale: number (Default: 0.125)

The minimum scale when zooming

Defined in

types.ts:204

step

Optional step: number (Default: 0.3)

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

Defined in

types.ts:208

PanzoomObject

These methods are available after initializing Panzoom.

eventNames

eventNames: Object

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

Type declaration

Name Type
down string
move string
up string

Defined in

types.ts:243

Methods

bind

bind(): void

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.

const panzoom = Panzoom(elem, { noBind: true })
// ...
panzoom.bind()

Returns

void

Defined in

types.ts:235

destroy

destroy(): void

Remove all event listeners bound to the the Panzoom element

Returns

void

Defined in

types.ts:237

getOptions

getOptions(): PanzoomOptions

Returns a copy of the current options object

Returns

PanzoomOptions

Defined in

types.ts:249

getPan

getPan(): Object

Get the current x/y translation

Returns

Object

Name Type
x number
y number

Defined in

types.ts:245

getScale

getScale(): number

Get the current scale

Returns

number

Defined in

types.ts:247

pan

pan(x, y, panOptions?): [CurrentValues](#CurrentValues)

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 })

Parameters

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

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:260

reset

reset(resetOptions?): [CurrentValues](#CurrentValues)

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 })

Parameters

Name Type
resetOptions? PanzoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:273

resetStyle

resetStyle(): void

Reset the styles set on the Panzoom element and its parent (such as overflow, cursor, etc.)

panzoom.resetStyle()

Returns

void

Defined in

types.ts:282

setOptions

setOptions(options?): void

Change any number of options on a Panzoom instance. Setting some options will have side-effects. For instance, changing the cursor option will also set the cursor style.

const panzoom = Panzoom(elem, { cursor: 'move' })
// ...
panzoom.setOptions({ cursor: 'default' })

Parameters

Name Type
options? PanzoomOptions

Returns

void

Defined in

types.ts:295

setStyle

setStyle(name, value): void

A convenience method for setting prefixed styles on the Panzoom element

Parameters

Name Type
name string
value string

Returns

void

Defined in

types.ts:297

zoom

zoom(scale, zoomOptions?): [CurrentValues](#CurrentValues)

Zoom the Panzoom element to the given scale

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

Parameters

Name Type
scale number
zoomOptions? ZoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:306

zoomIn

zoomIn(zoomOptions?): [CurrentValues](#CurrentValues)

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 })

Parameters

Name Type
zoomOptions? ZoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:317

zoomOut

zoomOut(zoomOptions?): [CurrentValues](#CurrentValues)

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 })

Parameters

Name Type
zoomOptions? ZoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:328

zoomToPoint

zoomToPoint(scale, point, zoomOptions?): [CurrentValues](#CurrentValues)

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)

Parameters

Name Type
scale number
point Object
point.clientX number
point.clientY number
zoomOptions? ZoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:339

zoomWithWheel

zoomWithWheel(event, zoomOptions?): [CurrentValues](#CurrentValues)

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.

Notes:

  • the focal point zooming pan adjustment is not affected by the disablePan option.
  • animate should not be used when zooming with the wheel, and is therefore always disabled.
// 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)
})

Parameters

Name Type
event WheelEvent
zoomOptions? ZoomOptions

Returns

[CurrentValues](#CurrentValues)

Defined in

types.ts:372

CurrentValues

isSVG

Optional isSVG: boolean

Defined in

types.ts:219

scale

scale: number

Defined in

types.ts:218

x

x: number

Defined in

types.ts:216

y

y: number

Defined in

types.ts:217

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.