maettig/LICENSE.txt

## README.md

      
    Raw
  

              README.md
            
          
    I implemented the imageconvolution() function from PHP in 140byt.es JavaScript. The function applies a 3 × 3 convolution matrix to an image. It can be used to create a surprisingly large amount of image filters like soften and sharpen.
Click here to see the script in action.
Note: It's possible to load images from foreign domains but due to security restrictions it's not possible to read and manipulate the pixel data from such images. Therefor the script will only work with images from the same domain.

  
## annotated.js
function(a, b, c, d, e, f, g)
{
  for (g = a.length;
    g--;                     //for all bytes in the pixel array
    b[g] = g % 4 > 2         //bytes 0, 1 and 2 are RGB, byte 3 is the alpha channel
      ? a[g]                 //copy alpha channel without changing it
      : j < 0                //limit the calculated sum to >=0
        ? 0
        : j >> 8             //limit the calculated sum to <=255
          ? 255              //Opera accepts -1 here, Firefox does not
          : j)
    for (var h = 9,          //the 3x3 matrix contains 9 values
             i = c,          //this is the offset in the pixel array
             j = f;          //start with the offset instead of adding it later
      h--;                   //for all values in the 3x3 matrix
      i -= h % 3             //decrease the offset in the pixel array
        ? 1                  //either by 1
        : c - 2)             //or by the image width
      j += a[g + i * 4 + 4]  //sum of 3x3 pixels
          * d[h] / e         //multiplied by the matrix, divided by the divisor
}

## index.js
function(a,b,c,d,e,f,g){for(g=a.length;g--;b[g]=g%4>2?a[g]:j<0?0:j>>8?255:j)for(var h=9,i=c,j=f;h--;i-=h%3?1:c-2)j+=a[g+i*4+4]*d[h]/e}

## LICENSE.txt
            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2012 Thiemo Mättig <http://maettig.com>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

## package.json
{
  "name": "imageconvolution",

  "description": "Apply a 3x3 convolution matrix to an image, using coefficient and offset.",

  "keywords": [
    "canvas",
    "filter",
    "image"
  ]
}

## test.html
<!DOCTYPE html>
<style>
label { text-align: right; width: 8em; }
label, .matrix { display: inline-block; vertical-align: top; }
</style>
<p><label>Preset:</label> <select onchange="loadPreset(this)">
<option value="0,0,0,0,1,0,0,0,0,1,0">None (identity)</option>
<option value="0,1,0,0,0,0,0,0,0,1,0">Shift down</option>
<option value="0,0,0,0,2,0,0,0,0,1,-255">Contrast</option>
<option value="0,0,0,0,1,0,0,0,0,2,127">Brighten</option>
<option value="0,0,0,0,-1,0,0,0,0,1,255">Invert</option>
<option value="0,1,0,1,4,1,0,1,0,8,0">Soften</option>
<option value="1,1,1,1,1,1,1,1,1,9,0">Blur</option>
<option value="0,-1,0,-1,8,-1,0,-1,0,4,0">Sharpen</option>
<option value="0,-2,0,-2,9,-2,0,-2,0,1,0">Enhance</option>
<option value="-1,0,0,0,1,0,0,0,1,1,0">Emboss</option>
<option value="-1,0,0,0,0,0,0,0,1,1,127">Relief</option>
<option value="0,-1,0,-1,4,-1,0,-1,0,1,255">Outline</option>
</select></p>
<label>Matrix:</label> <div class="matrix">
<input type="number" value="0"> <input type="number" value="0"> <input type="number" value="0"><br>
<input type="number" value="0"> <input type="number" value="1"> <input type="number" value="0"><br>
<input type="number" value="0"> <input type="number" value="0"> <input type="number" value="0">
</div>
<p><label>Divisor:</label> <input id="div" name="div" type="number" value="1"><br>
<label>Offset:</label> <input id="offset" name="offset" type="number" value="0"></p>
<p><label></label> <input type="button" value="Refresh" onclick="refresh(this)"></p>
<label>Image file:</label> <div class="matrix"><input id="url" name="url" size="45"></div>
<p><label></label> <input type="button" value="Load" onclick="load(this)"></p>
<p><canvas id="c"></canvas> <small>Loading...</small></p>
<script>
var imageconvolution = function(a,b,c,d,e,f,g){for(g=a.length;g--;b[g]=g%4>2?a[g]:j<0?0:j>>8?255:j)for(var h=9,i=c,j=f;h--;i-=h%3?1:c-2)j+=a[g+i*4+4]*d[h]/e}
function load()
{
  var s = inputs['url'].value.replace(/^\s+|\s+$/g, '');
  if (s && image.src != s) image.src = s;
}
function refresh()
{
  var matrix = [];
  for (var i = inputs.length; i--; ) matrix[i] = inputs[i].value * 1;
  var c = document.getElementsByTagName('canvas')[0];
  c.width = image.width;
  c.height = image.height;
  var a = c.getContext('2d');
  a.drawImage(image, 0, 0);
  try
  {
    var sourceData = a.getImageData(0, 0, c.width, c.height);
    var targetData = a.createImageData(sourceData);
    var t0 = new Date().getTime();
    imageconvolution(sourceData.data, targetData.data, sourceData.width, matrix,
      inputs['div'].value * 1, inputs['offset'].value * 1);
    var t1 = new Date().getTime();
    a.putImageData(targetData, 0, 0);
    document.getElementsByTagName('SMALL')[0].firstChild.data = '(' + Math.max(0, (t1 - t0) / 1000) + 's)';
  }
  catch (e) { alert(e); }
}
function loadPreset(a)
{
  a = a.options[a.selectedIndex].value.split(',');
  for (var i in a) document.getElementsByTagName('INPUT')[i].value = a[i];
  refresh();
}
var inputs = document.getElementsByTagName('INPUT');
var image = new Image();
image.onload = refresh;
</script>
	function(a, b, c, d, e, f, g)
	{
	for (g = a.length;
	g--; //for all bytes in the pixel array
	b[g] = g % 4 > 2 //bytes 0, 1 and 2 are RGB, byte 3 is the alpha channel
	? a[g] //copy alpha channel without changing it
	: j < 0 //limit the calculated sum to >=0
	? 0
	: j >> 8 //limit the calculated sum to <=255
	? 255 //Opera accepts -1 here, Firefox does not
	: j)
	for (var h = 9, //the 3x3 matrix contains 9 values
	i = c, //this is the offset in the pixel array
	j = f; //start with the offset instead of adding it later
	h--; //for all values in the 3x3 matrix
	i -= h % 3 //decrease the offset in the pixel array
	? 1 //either by 1
	: c - 2) //or by the image width
	j += a[g + i * 4 + 4] //sum of 3x3 pixels
	* d[h] / e //multiplied by the matrix, divided by the divisor
	}
	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
	Version 2, December 2004

	Copyright (C) 2012 Thiemo Mättig <http://maettig.com>

	Everyone is permitted to copy and distribute verbatim or modified
	copies of this license document, and changing it is allowed as long
	as the name is changed.

	DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
	TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

	0. You just DO WHAT THE FUCK YOU WANT TO.
	{
	"name": "imageconvolution",

	"description": "Apply a 3x3 convolution matrix to an image, using coefficient and offset.",

	"keywords": [
	"canvas",
	"filter",
	"image"
	]
	}
	<!DOCTYPE html>
	<style>
	label { text-align: right; width: 8em; }
	label, .matrix { display: inline-block; vertical-align: top; }
	</style>
	<p><label>Preset:</label> <select onchange="loadPreset(this)">
	<option value="0,0,0,0,1,0,0,0,0,1,0">None (identity)</option>
	<option value="0,1,0,0,0,0,0,0,0,1,0">Shift down</option>
	<option value="0,0,0,0,2,0,0,0,0,1,-255">Contrast</option>
	<option value="0,0,0,0,1,0,0,0,0,2,127">Brighten</option>
	<option value="0,0,0,0,-1,0,0,0,0,1,255">Invert</option>
	<option value="0,1,0,1,4,1,0,1,0,8,0">Soften</option>
	<option value="1,1,1,1,1,1,1,1,1,9,0">Blur</option>
	<option value="0,-1,0,-1,8,-1,0,-1,0,4,0">Sharpen</option>
	<option value="0,-2,0,-2,9,-2,0,-2,0,1,0">Enhance</option>
	<option value="-1,0,0,0,1,0,0,0,1,1,0">Emboss</option>
	<option value="-1,0,0,0,0,0,0,0,1,1,127">Relief</option>
	<option value="0,-1,0,-1,4,-1,0,-1,0,1,255">Outline</option>
	</select></p>
	<label>Matrix:</label> <div class="matrix">
	<input type="number" value="0"> <input type="number" value="0"> <input type="number" value="0"><br>
	<input type="number" value="0"> <input type="number" value="1"> <input type="number" value="0"><br>
	<input type="number" value="0"> <input type="number" value="0"> <input type="number" value="0">
	</div>
	<p><label>Divisor:</label> <input id="div" name="div" type="number" value="1"><br>
	<label>Offset:</label> <input id="offset" name="offset" type="number" value="0"></p>
	<p><label></label> <input type="button" value="Refresh" onclick="refresh(this)"></p>
	<label>Image file:</label> <div class="matrix"><input id="url" name="url" size="45"></div>
	<p><label></label> <input type="button" value="Load" onclick="load(this)"></p>
	<p><canvas id="c"></canvas> <small>Loading...</small></p>
	<script>
	var imageconvolution = function(a,b,c,d,e,f,g){for(g=a.length;g--;b[g]=g%4>2?a[g]:j<0?0:j>>8?255:j)for(var h=9,i=c,j=f;h--;i-=h%3?1:c-2)j+=a[g+i4+4]d[h]/e}
	function load()
	{
	var s = inputs['url'].value.replace(/^\s+\|\s+$/g, '');
	if (s && image.src != s) image.src = s;
	}
	function refresh()
	{
	var matrix = [];
	for (var i = inputs.length; i--; ) matrix[i] = inputs[i].value * 1;
	var c = document.getElementsByTagName('canvas')[0];
	c.width = image.width;
	c.height = image.height;
	var a = c.getContext('2d');
	a.drawImage(image, 0, 0);
	try
	{
	var sourceData = a.getImageData(0, 0, c.width, c.height);
	var targetData = a.createImageData(sourceData);
	var t0 = new Date().getTime();
	imageconvolution(sourceData.data, targetData.data, sourceData.width, matrix,
	inputs['div'].value * 1, inputs['offset'].value * 1);
	var t1 = new Date().getTime();
	a.putImageData(targetData, 0, 0);
	document.getElementsByTagName('SMALL')[0].firstChild.data = '(' + Math.max(0, (t1 - t0) / 1000) + 's)';
	}
	catch (e) { alert(e); }
	}
	function loadPreset(a)
	{
	a = a.options[a.selectedIndex].value.split(',');
	for (var i in a) document.getElementsByTagName('INPUT')[i].value = a[i];
	refresh();
	}
	var inputs = document.getElementsByTagName('INPUT');
	var image = new Image();
	image.onload = refresh;
	</script>