Lightweight Javascript ImageCropper

A lightweight javascript imagecropper written in vanilla js with zero-dependency injection that builds itself into an object.

For a live preview and some example code, visit http://peterver.github.io/vanilla-image-cropper/

Getting Started

var img_c = new ImageCropper(selector, image, options);

selector

The selector is an html5 css selector ( such as '#myTestDiv' ), basically anything that works with a querySelector does the job.

It should point to the element where you want the imagecropper to be located.

image

The image can either be a javascript Image object loaded through a FileReader, this can be done like so

var reader = new FileReader();

reader.onload = function (evt) {
  var img_c = new ImageCropper(..., evt.target.result, ...);
};

reader.readAsDataURL(...myfile...);

Or you can simply pass an existing url, for example

var img_c = new ImageCropper(..., '../assets/my_img.jpg', ...);

options

There are several possible options defined for the image cropper

• max_width
  Sets the maximum width that the imagecropper can become
  
  
• max_height
  Sets the maximum height for the imagecropper
  
  
• min_crop_width
  The minimum width that the cropped image can be
  
  
• min_crop_height
  The miminum height that the cropped image can be
  
  
• create_cb
  A callback function that is called when the imagecropper has finished creating, this will pass an object containing the dimensions of the imagecropper ( for styling or positioning purposes )
  
  
• update_cb
  Callback function that is called everytime a move/change happens
  
  
• destroy_cb
  A callback function that is called when the imagecropper has finished destroying itself
  
  
• fixed_size
  A boolean ( true | false ), that tells the image cropper if it should constrain the size of the cropped area to be fixed or not ?
  
  
• mode (default = 'square')
  Sets the type of preview you should see when using the image cropper, possible options are
  • 'square'
  • 'circular'

Cropping an image (mime_type, quality)

When you're all done with your changes, you can crop the image by calling the crop function.

This will return a base64 string that you can then do some funky stuff with.

var img_b64_str = img_c.crop(mime_type, quality);
... // do some funky stuff here

mime_type ( default = 'image/jpeg')

The following mime_types are currently supported in this build, they need to be passed as a string value.

• image/jpeg
• image/png

Quality

The quality is a numeric value between 0 and 1. Where 1 is the highest quality setting, and 0 is the lowest quality setting.

Cleaning up an imagecropper instance

img_c = new ImageCropper('#test-imagecrop', 'img.jpg');
img_c.destroy();

or you can just delete the dom node that the image cropper was created in ( or its parent ), and the imagecropper instance will destroy itself :]

Example

For an example, check out the example folder in the repository

Author

Peter Vermeulen