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enhanshotjs

1.0.3 • Public • Published

About

threshold

Index

What and Why

Enhanshot.js is a javascript library for enhancing images with lightweight and easy way. So far there is only one action for enhancing image, I am going to add many enhance functions as well as Instagram or Tumblr.

Sample

Enhanshot.js Sample Page

Install

Download ZIP file

Download ZIP file and archive it. The only thing you need is files in dist folder.

Clone Github repository

Or, clone in your local repository.

$ git clone https://github.com/KENJU/enhanshot.git
cd enhanshot

Via Bower

You can also install Enhanshot.js through bower. Simply type below command.

$ bower install enhanshot

Via NPM

You can also install via npm.

$ npm install enhanshotjs

Usage

1. Import Script Files

There are three files in dist folder. Download all of them and import.

  • jquery.min.js(if you have not yet load jquery in your project)
  • enhanshot.min.js
  • worker.min.js
 
<script src="dist/jquery.min.js"></script>
<script src="dist/enhanshot.min.js"></script>
 

You do not have to load dist/worker.min.js because enhanshot.min.js load this file.

2. Select Effect

Firstly, just add class="convert-img" to image tags which you want to enhance.

And then, please add data-effect="???" attribute to the same img tag.

 
<img src="img/image.JPG" alt="" data-effect="enhance" class="convert-img">
 

Available data-effect

In the near future

  • currently being developped
    • blur
    • mirrorVertical
    • mirrorHorizontal
    • contrast

v1.0.2 (2015/06/03)

  • inherited from previous versions
    • enhance
    • grayscale
    • sepia
  • added from this version
    • negaposi
    • opacity
    • brighten
    • threshold
    • hueRotate
    • saturate

v1.0.1 (2015/06/02)

  • added from this version
    • enhance
    • grayscale
    • sepia

3. Call Function

Default

In default, any elements whose id name is convertBtn would trigger convert action. Therefore, add <button> or <a> with id name converBtn.

 
<button id="convertBtn">Convert!</button>
 
 
 
$('#convertBtn').on('click', function(e){
    Array.prototype.forEach.call(document.querySelectorAll('.row-right img'), function(node){
        process(node);
    });
});
 

Customize

Call process(img) function.

var img = $('#convert-target');
process(img);
 

Available Effects

enhance

Basic enhancement for all images from foods, portraits to natures.

Usage

 
<img src="img/image.JPG" alt="" data-effect="enhance" class="convert-img">
 

Tech-Background

var red = red * 1.24;
var green = green * 1.33;
var blue = green * 1.21;
 
enhance

grayscale

Make images to grayscale tone. Processing altorhitm is based on NTSC. For the detail please see the Wiki page about Grayscale, "Luma coding in video systems".

Usage

 
<img src="img/image.JPG" alt="" data-effect="grayscale" class="convert-img">
 

Tech-Background

The human eye is bad at seeing red and blue, so here red and blue color values are de-emphasized.

// calculated from NTSC
var red = red * .29;
var green = green * .58;
var blue = green * .11;
 
grayscale

sepia

Make images to sepia tone.

Usage

 
<img src="img/image.JPG" alt="" data-effect="sepia" class="convert-img">
 

Tech-Background

var red = red * 1.07;
var green = green * .74;
var blue = green * .43;
sepia

Negative-Positive

In negative-positive effect, each rgb values are simply converted.

Usage

 
<img src="img/image.JPG" alt="" data-effect="negaposi" class="convert-img">
 

Tech-Background

var red = 255 - red_original;
var blue = 255 - blue_original;
var green = 255 - green_original;
negaposit

Blur

Coming soon...

Mirror Vertically

Coming soon...

Mirror Horizontally

Coming soon...

Opacity

In the default script, alpha value is set to 50%.

Usage

 
<img src="img/image.JPG" alt="" data-effect="opacity" class="convert-img">
 

Tech-Background

var alpha = alpha_original * .5;
opacity

Brighten

Each rgb values are slighly enhanced.

Usage

 
<img src="img/image.JPG" alt="" data-effect="brighten" class="convert-img">
 

Tech-Background

var red += 5;
var blue += 5;
var green += 5;
brighten

Threshold

Make each pixels of a image only into black or white.

Usage

 
<img src="img/image.JPG" alt="" data-effect="threshold" class="convert-img">
 

Tech-Background

Calculate average value of red, green, blue and then check whether the average value is bigger than threshold value or not.

// threshold
threshold = (* .29 + g * .58 + b * .11); 
// average value
average = (+ g + b) * .33; 
// black or white
= (threshold >= average) ? 255 : 0; 
threshold

Hue Rotation

Change hue of images.

Usage

 
<img src="img/image.JPG" alt="" data-effect="hueRotate" class="convert-img">
 

Tech-Background

Firstly convert rgb to hsv, and then change hue values, and then re-convert hsv to rgb.

threshold

Saturation

Change saturation of images.

Usage

 
<img src="img/image.JPG" alt="" data-effect="saturate" class="convert-img">
 

Tech-Background

Basically the same algorirhum with Hue Rotation.

Firstly convert rgb to hsv, and then change hue values, and then re-convert hsv to rgb.

threshold

Contrast

Coming soon...

FAQ

Q. It's HEAVY plugin, ha?

A. No, Enhanshot.js uses Web Workers API

Usually, some processing about images or photos could be heavy and memory-consuming process, and such heavy plugin could lower the usability of clients sides.

However, thanks to Web Worker API, a heavy converting process is done under background, therefore it does not cost too much on user experiences.

Q. How do you do this enhancement process?

A. In below simple 3 steps

  1. Creates empty canvas
  2. Processes in worker thread because this process is heavy
  3. Draws enhanced canvas onto the image

Contact

Chekout out my blog, KJ's Blogging, or please contacts me via twitter.

Copyright and License

Code and documentation copyright Kenju Wagatsuma. Code released under the MIT license

install

npm i enhanshotjs

Downloadsweekly downloads

2

version

1.0.3

license

MIT

homepage

github.com

repository

Gitgithub

last publish

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