js裁剪图片

Cropper.js

JavaScript image cropper.

Website Photo Editor - An advanced example of Cropper.js. jquery-cropper - A jQuery plugin wrapper for Cropper.js. Table of contents Features Main Getting started Options Methods Events No conflict Browser support Contributing Versioning License Features Supports 39 options Supports 27 methods Supports 6 events Supports touch (mobile) Supports zooming Supports rotating Supports scaling (flipping) Supports multiple croppers Supports to crop on a canvas Supports to crop an image in the browser-side by canvas Supports to translate Exif Orientation information Cross-browser support Main

dist/ ├── cropper.css ├── cropper.min.css (compressed) ├── cropper.js (UMD) ├── cropper.min.js (UMD, compressed) ├── cropper.common.js (CommonJS, default) └── cropper.esm.js (ES Module) Getting started Installation

npm install cropperjs

In browser:

<link href="/path/to/cropper.css" rel="stylesheet"> <script src="/path/to/cropper.js"></script>

cdnjs provides CDN support for Cropper.js's CSS and JavaScript. You can find the links here.

Usage Syntax

new Cropper(element[, options])

element

Type: HTMLImageElement or HTMLCanvasElement The target image or canvas element for cropping.

options (optional)

Type: Object The options for cropping. Check out the available options. Example

<!-- Wrap the image or canvas element with a block element (container) --> <div> <img id="image" src="picture.jpg"> </div>

/* Ensure the size of the image fit the container perfectly */ img { display: block; /* This rule is very important, please don't ignore this */ max-width: 100%; }

// import 'cropperjs/dist/cropper.css'; import Cropper from 'cropperjs'; const image = document.getElementById('image'); const cropper = new Cropper(image, { aspectRatio: 16 / 9, crop(event) { console.log(event.detail.x); console.log(event.detail.y); console.log(event.detail.width); console.log(event.detail.height); console.log(event.detail.rotate); console.log(event.detail.scaleX); console.log(event.detail.scaleY); }, }); FAQ

How to crop a new area after zoom in or zoom out?

Just double-click your mouse to enter crop mode.

How to move the image after cropping an area?

Just double-click your mouse to enter move mode.

How to fix aspect ratio in free ratio mode?

Just hold the Shift key when you resize the crop box.

How to crop a square area in free ratio mode?

Just hold the Shift key when you crop on the image.

Notes

The size of the cropper inherits from the size of the image's parent element (wrapper), so be sure to wrap the image with a visible block element.

If you are using cropper in a modal, you should initialize the cropper after the modal is shown completely. Otherwise, you will not get the correct cropper.

The outputted cropped data is based on the original image size, so you can use them to crop the image directly.

If you try to start cropper on a cross-origin image, please make sure that your browser supports HTML5 CORS settings attributes, and your image server supports the Access-Control-Allow-Origin option (see the HTTP access control (CORS)).

Known issues

Known iOS resource limits: As iOS devices limit memory, the browser may crash when you are cropping a large image (iPhone camera resolution). To avoid this, you may resize the image first (preferably below 1024 pixels) before starting a cropper.

Known image size increase: When exporting the cropped image on the browser side with the HTMLCanvasElement.toDataURL method, the size of the exported image may be greater than the original image's. This is because the type of the exported image is not the same as the original image. So just pass the original image's type as the first parameter to toDataURL to fix this. For example, if the original type is JPEG, then use cropper.getCroppedCanvas().toDataURL('image/jpeg') to export image.

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Options

You may set cropper options with new Cropper(image, options). If you want to change the global default options, You may use Cropper.setDefaults(options).

viewMode Type: Number Default: 0 Options: 0: no restrictions 1: restrict the crop box not to exceed the size of the canvas. 2: restrict the minimum canvas size to fit within the container. If the proportions of the canvas and the container differ, the minimum canvas will be surrounded by extra space in one of the dimensions. 3: restrict the minimum canvas size to fill fit the container. If the proportions of the canvas and the container are different, the container will not be able to fit the whole canvas in one of the dimensions.

Define the view mode of the cropper. If you set viewMode to 0, the crop box can extend outside the canvas, while a value of 1, 2, or 3 will restrict the crop box to the size of the canvas. viewMode of 2 or 3 will additionally restrict the canvas to the container. There is no difference between 2 and 3 when the proportions of the canvas and the container are the same.

dragMode Type: String Default: 'crop' Options: 'crop': create a new crop box 'move': move the canvas 'none': do nothing

Define the dragging mode of the cropper.

initialAspectRatio Type: Number Default: NaN

Define the initial aspect ratio of the crop box. By default, it is the same as the aspect ratio of the canvas (image wrapper).

Only available when the aspectRatio option is set to NaN.

aspectRatio Type: Number Default: NaN

Define the fixed aspect ratio of the crop box. By default, the crop box has a free ratio.

data Type: Object Default: null

The previous cropped data you stored will be passed to the setData method automatically when initialized.

Only available when the autoCrop option had set to the true.

preview Type: Element, Array (elements), NodeList or String (selector) Default: '' An element or an array of elements or a node list object or a valid selector for Document.querySelectorAll

Add extra elements (containers) for preview.

Notes:

The maximum width is the initial width of the preview container. The maximum height is the initial height of the preview container. If you set an aspectRatio option, be sure to set the same aspect ratio to the preview container. If the preview does not display correctly, set the overflow: hidden style to the preview container. responsive Type: Boolean Default: true

Re-render the cropper when resizing the window.

restore Type: Boolean Default: true

Restore the cropped area after resizing the window.

checkCrossOrigin Type: Boolean Default: true

Check if the current image is a cross-origin image.

If so, a crossOrigin attribute will be added to the cloned image element, and a timestamp parameter will be added to the src attribute to reload the source image to avoid browser cache error.

Adding a crossOrigin attribute to the image element will stop adding a timestamp to the image URL and stop reloading the image. But the request (XMLHttpRequest) to read the image data for orientation checking will require a timestamp to bust cache to avoid browser cache error. You can set the checkOrientation option to false to cancel this request.

If the value of the image's crossOrigin attribute is "use-credentials", then the withCredentials attribute will set to true when read the image data by XMLHttpRequest.

checkOrientation Type: Boolean Default: true

Check the current image's Exif Orientation information. Note that only a JPEG image may contain Exif Orientation information.

Exactly, read the Orientation value for rotating or flipping the image, and then override the Orientation value with 1 (the default value) to avoid some issues (1, 2) on iOS devices.

Requires to set both the rotatable and scalable options to true at the same time.

Note: Do not trust this all the time as some JPG images may have incorrect (non-standard) Orientation values

Requires Typed Arrays support (IE 10+).

modal Type: Boolean Default: true

Show the black modal above the image and under the crop box.

guides Type: Boolean Default: true

Show the dashed lines above the crop box.

center Type: Boolean Default: true

Show the center indicator above the crop box.

highlight Type: Boolean Default: true

Show the white modal above the crop box (highlight the crop box).

background Type: Boolean Default: true

Show the grid background of the container.

autoCrop Type: Boolean Default: true

Enable to crop the image automatically when initialized.

autoCropArea Type: Number Default: 0.8 (80% of the image)

It should be a number between 0 and 1. Define the automatic cropping area size (percentage).

movable Type: Boolean Default: true

Enable to move the image.

rotatable Type: Boolean Default: true

Enable to rotate the image.

scalable Type: `Boolean Default: true

Enable to scale the image.

zoomable Type: Boolean Default: true

Enable to zoom the image.

zoomOnTouch Type: Boolean Default: true

Enable to zoom the image by dragging touch.

zoomOnWheel Type: Boolean Default: true

Enable to zoom the image by mouse wheeling.

wheelZoomRatio Type: Number Default: 0.1

Define zoom ratio when zooming the image by mouse wheeling.

cropBoxMovable Type: Boolean Default: true

Enable to move the crop box by dragging.

cropBoxResizable Type: Boolean Default: true

Enable to resize the crop box by dragging.

toggleDragModeOnDblclick Type: Boolean Default: true

Enable to toggle drag mode between "crop" and "move" when clicking twice on the cropper.

Requires dblclick event support.

minContainerWidth Type: Number Default: 200

The minimum width of the container.

minContainerHeight Type: Number Default: 100

The minimum height of the container.

minCanvasWidth Type: Number Default: 0

The minimum width of the canvas (image wrapper).

minCanvasHeight Type: Number Default: 0

The minimum height of the canvas (image wrapper).

minCropBoxWidth Type: Number Default: 0

The minimum width of the crop box.

Note: This size is relative to the page, not the image.

minCropBoxHeight Type: Number Default: 0

The minimum height of the crop box.

Note: This size is relative to the page, not the image.

ready Type: Function Default: null

A shortcut of the ready event.

cropstart Type: Function Default: null

A shortcut of the cropstart event.

cropmove Type: Function Default: null

A shortcut of the cropmove event.

cropend Type: Function Default: null

A shortcut of the cropend event.

crop Type: Function Default: null

A shortcut of the crop event.

zoom Type: Function Default: null

A shortcut of the zoom event.

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Methods

As there is an asynchronous process when loading the image, you should call most of the methods after ready, except setAspectRatio, replace and destroy.

If a method doesn't need to return any value, it will return the cropper instance (this) for chain composition.

new Cropper(image, { ready() { // this.cropper[method](argument1, , argument2, ..., argumentN); this.cropper.move(1, -1); // Allows chain composition this.cropper.move(1, -1).rotate(45).scale(1, -1); }, }); crop()

Show the crop box manually.

new Cropper(image, { autoCrop: false, ready() { // Do something here // ... // And then this.cropper.crop(); }, }); reset()

Reset the image and crop box to its initial states.

clear()

Clear the crop box.

replace(url[, hasSameSize])

url:

Type: String A new image url.

hasSameSize (optional):

Type: Boolean Default: false If the new image has the same size as the old one, then it will not rebuild the cropper and only update the URLs of all related images. This can be used for applying filters.

Replace the image's src and rebuild the cropper.

enable()

Enable (unfreeze) the cropper.

disable()

Disable (freeze) the cropper.

destroy()

Destroy the cropper and remove the instance from the image.

move(offsetX[, offsetY])

offsetX:

Type: Number Moving size (px) in the horizontal direction.

offsetY (optional):

Type: Number Moving size (px) in the vertical direction. If not present, its default value is offsetX.

Move the canvas (image wrapper) with relative offsets.

cropper.move(1); cropper.move(1, 0); cropper.move(0, -1); moveTo(x[, y])

x:

Type: Number The left value of the canvas

y (optional):

Type: Number The top value of the canvas If not present, its default value is x.

Move the canvas (image wrapper) to an absolute point.

zoom(ratio) ratio: Type: Number Zoom in: requires a positive number (ratio > 0) Zoom out: requires a negative number (ratio < 0)

Zoom the canvas (image wrapper) with a relative ratio.

cropper.zoom(0.1); cropper.zoom(-0.1); zoomTo(ratio[, pivot])

ratio:

Type: Number Requires a positive number (ratio > 0)

pivot (optional):

Type: Object Schema: { x: Number, y: Number } The coordinate of the center point for zooming, base on the top left corner of the cropper container.

Zoom the canvas (image wrapper) to an absolute ratio.

cropper.zoomTo(1); // 1:1 (canvasData.width === canvasData.naturalWidth) const containerData = cropper.getContainerData(); // Zoom to 50% from the center of the container. cropper.zoomTo(.5, { x: containerData.width / 2, y: containerData.height / 2, }); rotate(degree) degree: Type: Number Rotate right: requires a positive number (degree > 0) Rotate left: requires a negative number (degree < 0)

Rotate the image with a relative degree.

Requires CSS3 2D Transforms support (IE 9+).

cropper.rotate(90); cropper.rotate(-90); rotateTo(degree) degree: Type: Number

Rotate the image to an absolute degree.

scale(scaleX[, scaleY])

scaleX:

Type: Number Default: 1 The scaling factor to apply to the abscissa of the image. When equal to 1 it does nothing.

scaleY (optional):

Type: Number The scaling factor to apply on the ordinate of the image. If not present, its default value is scaleX.

Scale the image.

Requires CSS3 2D Transforms support (IE 9+).

cropper.scale(-1); // Flip both horizontal and vertical cropper.scale(-1, 1); // Flip horizontal cropper.scale(1, -1); // Flip vertical scaleX(scaleX) scaleX: Type: Number Default: 1 The scaling factor to apply to the abscissa of the image. When equal to 1 it does nothing.

Scale the abscissa of the image.

scaleY(scaleY) scaleY: Type: Number Default: 1 The scaling factor to apply on the ordinate of the image. When equal to 1 it does nothing.

Scale the ordinate of the image.

getData([rounded])

rounded (optional):

Type: Boolean Default: false Set true to get rounded values.

(return value):

Type: Object Properties: x: the offset left of the cropped area y: the offset top of the cropped area width: the width of the cropped area height: the height of the cropped area rotate: the rotated degrees of the image scaleX: the scaling factor to apply on the abscissa of the image scaleY: the scaling factor to apply on the ordinate of the image

Output the final cropped area position and size data (base on the natural size of the original image).

You can send the data to the server-side to crop the image directly:

Rotate the image with the rotate property. Scale the image with the scaleX and scaleY properties. Crop the image with the x, y, width, and height properties.

setData(data) data: Type: Object Properties: See the getData method. You may need to round the data properties before passing them in.

Change the cropped area position and size with new data (base on the original image).

Note: This method only available when the value of the viewMode option is greater than or equal to 1.

getContainerData() (return value): Type: Object Properties: width: the current width of the container height: the current height of the container

Output the container size data.

getImageData() (return value): Type: Object Properties: left: the offset left of the image top: the offset top of the image width: the width of the image height: the height of the image naturalWidth: the natural width of the image naturalHeight: the natural height of the image aspectRatio: the aspect ratio of the image rotate: the rotated degrees of the image if it is rotated scaleX: the scaling factor to apply on the abscissa of the image if scaled scaleY: the scaling factor to apply on the ordinate of the image if scaled

Output the image position, size, and other related data.

getCanvasData() (return value): Type: Object Properties: left: the offset left of the canvas top: the offset top of the canvas width: the width of the canvas height: the height of the canvas naturalWidth: the natural width of the canvas (read only) naturalHeight: the natural height of the canvas (read only)

Output the canvas (image wrapper) position and size data.

const imageData = cropper.getImageData(); const canvasData = cropper.getCanvasData(); if (imageData.rotate % 180 === 0) { console.log(canvasData.naturalWidth === imageData.naturalWidth); // > true } setCanvasData(data) data: Type: Object Properties: left: the new offset left of the canvas top: the new offset top of the canvas width: the new width of the canvas height: the new height of the canvas

Change the canvas (image wrapper) position and size with new data.

getCropBoxData() (return value): Type: Object Properties: left: the offset left of the crop box top: the offset top of the crop box width: the width of the crop box height: the height of the crop box

Output the crop box position and size data.

setCropBoxData(data) data: Type: Object Properties: left: the new offset left of the crop box top: the new offset top of the crop box width: the new width of the crop box height: the new height of the crop box

Change the crop box position and size with new data.

getCroppedCanvas([options])

options (optional):

Type: Object Properties: width: the destination width of the output canvas. height: the destination height of the output canvas. minWidth: the minimum destination width of the output canvas, the default value is 0. minHeight: the minimum destination height of the output canvas, the default value is 0. maxWidth: the maximum destination width of the output canvas, the default value is Infinity. maxHeight: the maximum destination height of the output canvas, the default value is Infinity. fillColor: a color to fill any alpha values in the output canvas, the default value is the transparent. imageSmoothingEnabled: set to change if images are smoothed (true, default) or not (false). imageSmoothingQuality: set the quality of image smoothing, one of "low" (default), "medium", or "high".

(return value):

Type: HTMLCanvasElement A canvas drawn the cropped image.

Notes:

The aspect ratio of the output canvas will be fitted to the aspect ratio of the crop box automatically. If you intend to get a JPEG image from the output canvas, you should set the fillColor option first, if not, the transparent part in the JPEG image will become black by default. Uses the Browser's native canvas.toBlob API to do the compression work, which means it is lossy compression. For better image quality, you can upload the original image and the cropped data to a server and do the crop work on the server.

Browser support:

Basic image: requires Canvas support (IE 9+). Rotated image: requires CSS3 2D Transforms support (IE 9+). Cross-origin image: requires HTML5 CORS settings attributes support (IE 11+).

Get a canvas drawn from the cropped image (lossy compression). If it is not cropped, then returns a canvas drawn the whole image.

After then, you can display the canvas as an image directly, or use HTMLCanvasElement.toDataURL to get a Data URL, or use HTMLCanvasElement.toBlob to get a blob and upload it to server with FormData if the browser supports these APIs.

Avoid get a blank (or black) output image, you might need to set the maxWidth and maxHeight properties to limited numbers, because of the size limits of a canvas element. Also, you should limit the maximum zoom ratio (in the zoom event) for the same reason.

cropper.getCroppedCanvas(); cropper.getCroppedCanvas({ width: 160, height: 90, minWidth: 256, minHeight: 256, maxWidth: 4096, maxHeight: 4096, fillColor: '#fff', imageSmoothingEnabled: false, imageSmoothingQuality: 'high', }); // Upload cropped image to server if the browser supports `HTMLCanvasElement.toBlob`. // The default value for the second parameter of `toBlob` is 'image/png', change it if necessary. cropper.getCroppedCanvas().toBlob((blob) => { const formData = new FormData(); // Pass the image file name as the third parameter if necessary. formData.append('croppedImage', blob/*, 'example.png' */); // Use `jQuery.ajax` method for example $.ajax('/path/to/upload', { method: 'POST', data: formData, processData: false, contentType: false, success() { console.log('Upload success'); }, error() { console.log('Upload error'); }, }); }/*, 'image/png' */); setAspectRatio(aspectRatio) aspectRatio: Type: Number Requires a positive number.

Change the aspect ratio of the crop box.

setDragMode([mode]) mode (optional): Type: String Default: 'none' Options: 'none', 'crop', 'move'

Change the drag mode.

Tips: You can toggle the "crop" and "move" mode by double click on the cropper.

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Events ready

This event fires when the target image has been loaded and the cropper instance is ready for operating.

let cropper; image.addEventListener('ready', function () { console.log(this.cropper === cropper); // > true }); cropper = new Cropper(image); cropstart

event.detail.originalEvent:

Type: Event Options: pointerdown, touchstart, and mousedown

event.detail.action:

Type: String Options: 'crop': create a new crop box 'move': move the canvas (image wrapper) 'zoom': zoom in / out the canvas (image wrapper) by touch. 'e': resize the east side of the crop box 'w': resize the west side of the crop box 's': resize the south side of the crop box 'n': resize the north side of the crop box 'se': resize the southeast side of the crop box 'sw': resize the southwest side of the crop box 'ne': resize the northeast side of the crop box 'nw': resize the northwest side of the crop box 'all': move the crop box (all directions)

This event fires when the canvas (image wrapper) or the crop box starts to change.

image.addEventListener('cropstart', (event) => { console.log(event.detail.originalEvent); console.log(event.detail.action); }); cropmove

event.detail.originalEvent:

Type: Event Options: pointermove, touchmove, and mousemove.

event.detail.action: the same as "cropstart".

This event fires when the canvas (image wrapper) or the crop box is changing.

cropend

event.detail.originalEvent:

Type: Event Options: pointerup, pointercancel, touchend, touchcancel, and mouseup.

event.detail.action: the same as "cropstart".

This event fires when the canvas (image wrapper) or the crop box stops to change.

crop event.detail.x event.detail.y event.detail.width event.detail.height event.detail.rotate event.detail.scaleX event.detail.scaleY

About these properties, see the getData method.

This event fires when the canvas (image wrapper) or the crop box changed.

Notes:

When the autoCrop option is set to the true, a crop event will be triggered before the ready event. When the data option is set, another crop event will be triggered before the ready event. zoom

event.detail.originalEvent:

Type: Event Options: wheel, pointermove, touchmove, and mousemove.

event.detail.oldRatio:

Type: Number The old (current) ratio of the canvas

event.detail.ratio:

Type: Number The new (next) ratio of the canvas (canvasData.width / canvasData.naturalWidth)

This event fires when a cropper instance starts to zoom in or zoom out its canvas (image wrapper).

image.addEventListener('zoom', (event) => { // Zoom in if (event.detail.ratio > event.detail.oldRatio) { event.preventDefault(); // Prevent zoom in } // Zoom out // ... });

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No conflict

If you have to use another cropper with the same namespace, just call the Cropper.noConflict static method to revert to it.

<script src="other-cropper.js"></script> <script src="cropper.js"></script> <script> Cropper.noConflict(); // Code that uses other `Cropper` can follow here. </script> Browser support Chrome (latest) Firefox (latest) Safari (latest) Opera (latest) Edge (latest) Internet Explorer 9+ Contributing

Please read through our contributing guidelines.

Versioning

Maintained under the Semantic Versioning guidelines.

License

MIT © Chen Fengyuan

Related projects angular-cropperjs by @matheusdavidson ember-cropperjs by @danielthall iron-cropper by @safetychanger react-cropper by @roadmanfong vue-cropperjs by @Agontuk

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