Extensible, mobile friendly pan and zoom framework (supports DOM and SVG).
- Regular DOM object
- Standalone page - this repository
- YASIV - my hobby project
- SVG Tiger - js fiddle
Grab it from npm and use with your favorite bundler:
npm install panzoom --save
Or download from CDN:
<script src='https://unpkg.com/panzoom@7.1.2/dist/panzoom.min.js'></script>
If you download from CDN the library will be available under panzoom global name.
// just grab any DOM element
var area = document.querySelector('.zoomable')
// And pass it to panzoom
panzoom(area)<!-- this is your html file with svg -->
<body>
<svg>
<!-- this is the draggable root -->
<g id='scene'>
<circle cx='10' cy='10' r='5' fill='pink'></circle>
</g>
</svg>
</body>// In the browser panzoom is already on the
// window. If you are in common.js world, then
// var panzoom = require('panzoom')
// grab the DOM SVG element that you want to be draggable/zoomable:
var scene = document.getElementById('scene')
// and forward it it to panzoom.
panzoom(scene)If your use case requires dynamic behavior (i.e. you want to make a scene not
draggable anymore, or even completely delete an SVG element) make sure to call
dispose() method:
var instance = panzoom(scene)
// do work
// ...
// then at some point you decide you don't need this anymore:
instance.dispose()This will make sure that all event handlers are cleared and you are not leaking memory
The library allows to subscribe to transformation changing events. E.g. when
user starts/ends dragging the scene, the scene will fire panstart/panend
events. Here is example of all supported events:
var instance = panzoom(scene);
instance.on('panstart', function(e) {
console.log('Fired when pan is just started ', e);
// Note: e === instance.
});
instance.on('pan', function(e) {
console.log('Fired when the scene is being panned', e);
});
instance.on('panend', function(e) {
console.log('Fired when pan ended', e);
});
instance.on('zoom', function(e) {
console.log('Fired when scene is zoomed', e);
});
instance.on('transform', function(e) {
// This event will be called along with events above.
console.log('Fired when any transformation has happened', e);
});See JSFiddle console for a demo.
Sometimes zooming interferes with scrolling. If you want to alleviate it you can provide a custom filter, which will allow zooming only when modifier key is down. E.g.
panzoom(document.getElementById('g4'), {
beforeWheel: function(e) {
// allow wheel-zoom only if altKey is down. Otherwise - ignore
var shouldIgnore = !e.altKey;
return shouldIgnore;
}
});See JSFiddle for the demo. The tiger will be
zoomable only when Alt key is down.
By default, panzoom will listen to keyboard events, so that users can navigate the scene
with arrow keys and +, - signs to zoom out. If you don't want this behavior you can
pass the filterKey() predicate that returns truthy value to prevent panzoom's default
behavior:
panzoom(document.getElementById('g4'), {
filterKey: function(/* e, dx, dy, dz */) {
// don't let panzoom handle this event:
return true;
}
});You can adjust how fast it zooms, by passing optional zoomSpeed argument:
panzoom(document.getElementById('g4'), {
zoomSpeed: 0.065 // 6.5% per mouse wheel event
});You can set min and max zoom, by passing optional minZoom and maxZoom argument:
panzoom(document.getElementById('g4'), {
maxZoom: 1,
minZoom: 0.1
});You can disable smooth scroll, by passing optional smoothScroll argument:
panzoom(document.getElementById('g4'), {
smoothScroll: false
});With this setting the momentum is disabled.
You can pause and resume the panzoom by calling the following methods:
var controller = panzoom(document.getElementById('g4'));
controller.isPaused(); // returns false
controller.pause(); // Pauses event handling
controller.isPaused(); // returns true now
controller.resume(); // Resume panzoom
controller.isPaused(); // returns false againIf you want to quickly play with panzoom without using javascript, you can configure it via
script tag:
<!-- this is your html file -->
<!DOCTYPE html>
<html>
<head>
<script src='https://unpkg.com/panzoom@7.1.2/dist/panzoom.min.js'
query='#scene' name='pz'></script>
</head>
<body>
<svg>
<!-- this is the draggable root -->
<g id='scene'>
<circle cx='10' cy='10' r='5' fill='pink'></circle>
</g>
</svg>
</body>
</html>Most importantly, you can see query attribute that points to CSS selector. Once the element is found
panzoom is attached to this element. The controller will become available under window.pz name. And you
can pass additional options to the panzoom via attributes prefixed with pz-.
Here is a demo: Script based attributes
You can adjust the double click zoom multiplier, by passing optional zoomDoubleClickSpeed argument.
When double clicking, zoom is multiplied by zoomDoubleClickSpeed, which means that a value of 1 will disable double click zoom completely.
panzoom(document.getElementById('g4'), {
zoomDoubleClickSpeed: 1,
});You can set the initial position and zoom, by chaining the zoomAbs function with x position, y position and zoom as arguments:
panzoom(document.getElementById('g4'), {
maxZoom: 1,
minZoom: 0.1
}).zoomAbs(
300, // initial x position
500, // initial y position
0.1 // initial zoom
);The library will handle ontouch events very aggressively, it will preventDefault, and
stopPropagation for the touch events inside container. Sometimes this is not a desirable behavior.
If you want to take care about this yourself, you can pass onTouch callback to the options object:
panzoom(document.getElementById('g4'), {
onTouch: function(e) {
// `e` - is current touch event.
return false; // tells the library to not preventDefault.
}
});Note: if you don't preventDefault yourself - make sure you test the page behavior on iOS devices.
Sometimes this may cause page to bounce undesirably.
By default panzoom will prevent default action on double click events - this is done to avoid
accidental text selection (which is default browser action on double click). If you prefer to
allow default action, you can pass onDoubleClick() callback to options. If this callback
returns false, then the library will not prevent default action:
panzoom(document.getElementById('g4'), {
onDoubleClick: function(e) {
// `e` - is current double click event.
return false; // tells the library to not preventDefault, and not stop propagation
}
});MIT