svg.panzoom.js

> A plugin for svg.js that enables panzoom for svg elements

Getting started

``
npm install @svgdotjs/svg.js @svgdotjs/svg.panzoom.js
`

Include this plugin after including the svg.js library in your html document.

`


`

Or for esm just import it:

`
import { SVG } from '@svgdotjs/svg.js'
import '@svgdotjs/svg.panzoom.js'
`

To enable pan/zoom on an svg:

`js
// enables panZoom
var canvas = SVG()
.addTo('#id')
.size(1000, 1000)
.panZoom()

// zoom programatically
canvas.zoom(lvl, point)
`

You can configure panZoom by passing options to it.

- zoomMin: Minimal zoom level
- zoomMax: Maximal zoom level
- zoomFactor: How much is zoomed by one mouse wheel step

This could look like this:

`js
var canvas = SVG()
.addTo('#id')
.size(1000, 1000)
.panZoom({ zoomMin: 0.5, zoomMax: 20 })
`

Setting the min and max value will automatically restrict the zoom to the provided level.
However you are still able to change the zoom out of that bonds by calling zoom(lvl) programatically.

On touchable devices a pinchZoom gesture is supported. Min and max values also apply here.

Zooming is animatable, too:

`js
canvas
.zoom(1) // uses center of viewport by default
.animate()
.zoom(2, { x: 100, y: 100 }) // zoom into specified point
`

To disable panZoom or change its options just call it again with false or the new options.

Options

You can override the default options by passing an object in to the .panZoom({options}) call.

| Option | Default | Description |
| ------------ | ---------------- | -------------------------------------------------------------------------------------------------------------- |
| panning | true | Enable panning |
| pinchZoom | true | Enable pinch to zoom |
| wheelZoom | true | Enable mouse wheel zoom |
| panButton | 0 | Which mouse button to use for pan (info) |
| oneFingerPan | false | Enables the ability to pan with only one finger instead of two for touchdevices |
| margins | false | An object {top, left, right, bottom} to restrict the pan area towards this side so that at least x user units of the opposite side are still visible |
| zoomFactor | 2 | How quickly to zoom when using wheelZoom |
| zoomMin | Number.MIN_VALUE | The minimum zoom level |
| zoomMax | Number.MAX_VALUE | The maximum zoom level |
| wheelZoomDeltaModeLinePixels | 17 | The multiplier to convert wheel zoom deltaY values from deltaMode=1 (lines) to deltaMode=0 (pixels) |
| wheelZoomDeltaModeScreenPixels | 53 | The multiplier to convert wheel zoom deltaY values from deltaMode=2 (screen) to deltaMode=0 (pixels) |

$3

`js
draw.panZoom({
wheelZoom: false,
zoomMin: 0.5,
zoomMax: 2
})
`

This will disable wheel zooming and set the maximum zoom to 2 or 200% and the minimum zoom to 0.5 or 50%.

Events

Multiple events are fired doing different actions. This allow you to respond
to actions and in some cases stop an action via preventDefault().

zoom is fired when a mouse wheel event or programmable zoom() triggers
a zoom. This usually doesn't happen on mobile devices, in which case
pinchZoomStart is fired when a zoom happens.

Events fired from SVG.js are CustomEvents,
so the arguments passed from svg.panzoom.js are in in the .detail property.

| Event Name | Argument Value | preventDefault support |
| -------------- | ---------------- | ---------------------- |
| zoom | { lvl, focus } | YES |
| panStart | { event } | NO |
| panEnd | { event } | NO |
| panning | { box } | YES |
| pinchZoomStart | { event } | YES |
| pinchZoomEnd | { event } | NO |

Where lvl is the new zoom level,
focus is th point of zoom, box is the new calculated viewbox
and event is the event that triggered the action.

An example of stopping a pinch-zoom action:

`js
var canvas = SVG()
.addTo('#id')
.size(1000, 1000)
.panZoom()

canvas.on('pinchZoomStart', function (ev) {
ev.preventDefault()
// ...
})
``