PHParadise | category image editing | copy source code of invert image

PHParadise > image editing > invert image

This PHP function uses the GD library to invert color or black and white images.
You can choose wether you want to save the negative of the image or just display it.
choose color or black and white output - works with .jpg and .png images if your GD-Library supports it.

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<?php

/*------------------------------------------------------------------------------
|
|                             PHParadise source code
|
|-------------------------------------------------------------------------------
|
| file:             invert image
| category:         image editing
|
| last modified:    Wed, 02 Nov 2005 21:53:34 GMT
| downloaded:       Fri, 25 May 2012 03:05:19 GMT as copy from textarea
|
| code URL:
| http://phparadise.de/php-code/image-editing/invert-image/
|
| description:
| This PHP function uses the GD library to invert color or black and white images.
| You can choose wether you want to save the negative of the image or just display
| it. choose color or black and white output - works with .jpg and .png images if
| your GD-Library supports it.
|
------------------------------------------------------------------------------*/

function invert_image($input,$output,$color=false,$type='jpeg')
{
	if($type == 'jpeg') $bild = imagecreatefromjpeg($input);
	else $bild = imagecreatefrompng($input);

$x = imagesx($bild);
	$y = imagesy($bild);
 
	for($i=0; $i<$y; $i++)
	{
		for($j=0; $j<$x; $j++)
		{
			$pos = imagecolorat($bild, $j, $i);
			$f = imagecolorsforindex($bild, $pos);
			if($color == true)
			{
				$col = imagecolorresolve($bild, 255-$f['red'], 255-$f['green'], 255-$f['blue']);
			}else{
				$gst = $f['red']*0.15 + $f['green']*0.5 + $f['blue']*0.35;
				$col = imagecolorclosesthwb($bild, 255-$gst, 255-$gst, 255-$gst);
			}
			imagesetpixel($bild, $j, $i, $col);
		}
	}
	if(empty($output)) header('Content-type: image/'.$type);
	if($type == 'jpeg') imagejpeg($bild,$output,90);
	else imagepng($bild,$output);
}

$input = 'path/to/image.jpg';

// for a color negative image, set the optional flag
invert_image($input,'',true);

// for a black and withe negative image use like this
//
// invert_image($input,'');

// if you want to save the output instead of just showing it,
// set the output to the path where you want to save the inverted image
//
// invert_image('path/to/original/image.jpg','path/to/save/inverted-image.jpg');

// if you want to use png you have to set the color flag as
// true or false and define the imagetype in the function call
//
// invert_image('path/to/image.png','',false,'png');

PHParadise source code of “invert image” in category “image editing”

PHParadise > image editing > invert image

copy the code of image editing / invert image