README

vanilla-js-wheel-zoom

Image resizing using mouse wheel (pinch to zoom) + drag scrollable image (as well as any HTML content)

GitHub tag (latest by date)

Advantages:

the ability to fit the image into a container of any proportion
the ability to scale any HTML content
touch screen devices support

Starting with version 5, the plugin switched to using style transform. To use the plugin in older browsers, switch to earlier versions.

You need to center the image (or any HTML content) in the "window" in which scaling will take place. The "window" is taken automatically as the parent of the image in DOM.

HTML content can be of any structure, but the topmost child element in the “window” must be one. In the example with "badge" below, it will be more clear what is meant.

🖐 If you find my plugin helpful, please donate me 🤝

Demo (only one image)

Demo (html)

Demo (multi images with custom align)

Playground... Have some fun 🤸‍♂️

Install

npm i vanilla-js-wheel-zoom

yarn add vanilla-js-wheel-zoom

Get started

#myWindow {
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: #999;
}

#myContent {
    position: relative;
    display: flex;
    align-items: center;
}

<div id="myWindow" style="width:600px;height:600px;">
    <img id="myContent" src="https://placehold.it/2400x1400" alt="image" />
</div>

WZoom.create('#myContent');

Supported "hotswap" src of image (when type = image). You can do document.getElementById('myContent').src = "_new_path_" after initializing the plugin.

Syntax & Parameters

/**
 * Create WZoom instance
 * @param {string|HTMLElement} selectorOrHTMLElement
 * @param {Object} [options]
 * @returns {WZoom}
 */
const wzoom = WZoom.create(selectorOrHTMLElement[, options]);

Default options

const defaults = {
    // type content: `image` - only one image, `html` - any HTML content
    type: 'image',
    // for type `image` computed auto (if width set null), for type `html` need set real html content width, else computed auto
    width: null,
    // for type `image` computed auto (if height set null), for type `html` need set real html content height, else computed auto
    height: null,
    // drag scrollable image
    dragScrollable: true,
    // options for the DragScrollable module
    dragScrollableOptions: {
        // smooth extinction (value in seconds)
        smoothExtinction: .25,
        // callback triggered when grabbing an element
        onGrab: null,
        // callback triggered when moving an element
        onMove: null,
        // callback triggered when dropping an element
        onDrop: null
    },
    // minimum allowed proportion of scale (computed auto if null)
    minScale: null,
    // maximum allowed proportion of scale (1 = 100% content size)
    maxScale: 1,
    // image resizing speed
    speed: 10,
    // zoom to maximum (minimum) size on click
    zoomOnClick: true,
    // if is true, then when the source image changes, the plugin will automatically restart init function (used with type = image)
    // attention: if false, it will work correctly only if the images are of the same size
    watchImageChange: true,
    // smooth extinction (value in seconds)
    smoothExtinction: .3,
    // align content `center`, `left`, `top`, `right`, `bottom` 
    alignContent: 'center',
    /********************/
    disableWheelZoom: false
};

Badge on the image

#myWindow {
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: aqua;
}

#myContent {
    position: relative;
    display: flex;
    align-items: center;
}

#myBadge {
    position: absolute;
    border: solid 2px red;
    font-size: 80px;
}

#myImage {
    display: block;
    width: auto;
    height: auto;
    margin: auto;
    align-self: center;
    flex-shrink: 0;
}

<div id="myWindow" style="width:600px;height:600px;">
    <div id="myContent">
        <div id="myBadge" style="left:900px;top:500px;">Badge</div>
        <img id="myImage" src="https://placehold.it/2500x1500" alt="image"/>
    </div>
</div>

WZoom.create('#myContent', {
    type: 'html',
    width: 2500,
    height: 1500
});

Control buttons

<button data-zoom-up>Zoom Up</button>
<button data-zoom-down>Zoom Down</button>

const wzoom = WZoom.create('img');

document.querySelector('[data-zoom-up]').addEventListener('click', () => {
    wzoom.zoomUp();
});

document.querySelector('[data-zoom-down]').addEventListener('click', () => {
    wzoom.zoomDown();
});

On window resize

const wzoom = WZoom.create('img');

window.addEventListener('resize', () => {
    wzoom.prepare();
});

How to rotate the image?

Try this 😉 (and see demo)

Options

name	type	default	note
type	String	`image`	`image` - if you need to scale only one image. In this case, there is no need to pass the parameters `width` and `height`. `html` - if you need to scale the HTML code. It is advisable to specify the parameters `width` and `height` that correspond to the original full size of the HTML content.
width	Number	`null`	For type `image` computed auto (if width set null), for type `html` need set real html content width, else computed auto.
height	Number	`null`	For type `image` computed auto (if height set null), for type `html` need set real html content height, else computed auto.
dragScrollable	Boolean	`true`	If `true` - scaled image can be dragged with the mouse to see parts of the image that are out of scale.
dragScrollableOptions.smoothExtinction	Number	`.25`	Time of smooth extinction. if `0` then no smooth extinction. (value in seconds)
dragScrollableOptions.onGrab	Function	`undefined`	Called after grabbing an element.
dragScrollableOptions.onMove	Function	`undefined`	Called on every tick when moving element.
dragScrollableOptions.onDrop	Function	`undefined`	Called after dropping an element.
minScale	Number	`null`	The minimum scale to which the image can be zoomed. If `falsy` or greater than `maxScale` then computed auto.
maxScale	Number	`1`	The maximum scale to which the image can be zoomed. `1` means that the image can be maximized to 100%, `2` - 200%, etc.
speed	Number	`10`	Step with which the image will be scaled. Measured in relative units. The larger the value, the smaller the step and vice versa.
zoomOnClick	Boolean	`true`	Zoom to maximum (minimum) size on click.
watchImageChange	Boolean	`true`	If is `true`, then when the source image changes, the plugin will automatically restart init function (used with `type = image`). Attention: if `false`, it will work correctly only if the images are of the same size.
prepare	Function	`undefined`	Called after the script is initialized when the image is scaled and fit into the container.
rescale	Function	`undefined`	Called on every change of scale.
alignContent	String	`center`	Align content `center`, `left`, `top`, `right`, `bottom`
smoothExtinction	Number	`.3`	Time of smooth extinction. if `0` then no smooth extinction. (value in seconds)
disableWheelZoom	Boolean	`false`

API

name	note
.prepare()	Reinitialize script
.zoomUp()	Zoom on one step (see option `speed`)
.maxZoomUp()	Zoom to max scale
.zoomDown()	Zoom out on one step (see option `speed`)
.maxZoomDown()	Zoom to min scale
.destroy()	Destroy object

LICENSE

vanilla-js-wheel-zoom is licensed under the GPLv3 license for all open source applications. A commercial license is required for all commercial applications (including sites, themes and apps you plan to sell).

Usage no npm install needed!