imagefilter

(PHP 5)

imagefilter --  Applies a filter to an image

Description

bool imagefilter ( resource src_im, int filtertype [, int arg1 [, int arg2 [, int arg3]]] )

imagefilter() applies the filter filtertype to the image, using arg1, arg2 and arg3 where necessary.

filtertype can be one of the following:

  • IMG_FILTER_NEGATE: Reverses all colors of the image.

  • IMG_FILTER_GRAYSCALE: Converts the image into grayscale.

  • IMG_FILTER_BRIGHTNESS: Changes the brightness of the image. Use arg1 to set the level of brightness.

  • IMG_FILTER_CONTRAST: Changes the contrast of the image. Use arg1 to set the level of contrast.

  • IMG_FILTER_COLORIZE: Like IMG_FILTER_GRAYSCALE, except you can specify the color. Use arg1, arg2 and arg3 in the form of red, blue, green. The range for each color is 0 to 255.

  • IMG_FILTER_EDGEDETECT: Uses edge detection to highlight the edges in the image.

  • IMG_FILTER_EMBOSS: Embosses the image.

  • IMG_FILTER_GAUSSIAN_BLUR: Blurs the image using the Gaussian method.

  • IMG_FILTER_SELECTIVE_BLUR: Blurs the image.

  • IMG_FILTER_MEAN_REMOVAL: Uses mean removal to achieve a "sketchy" effect.

  • IMG_FILTER_SMOOTH: Makes the image smoother. Use arg1 to set the level of smoothness.

Замечание: Эта функция доступна только в том случае, если PHP был скомпилирован со встроенной библиотекой GD.

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.

Пример 1. imagefilter() grayscale example

<?php
$im = imagecreatefrompng('dave.png');
if ($im && imagefilter($im, IMG_FILTER_GRAYSCALE)) {
   echo 'Image converted to grayscale.';
   imagepng($im, 'dave.png');
} else {
   echo 'Conversion to grayscale failed.';
}

imagedestroy($im);
?>

Пример 2. imagefilter() brightness example

<?php
$im = imagecreatefrompng('sean.png');
if ($im && imagefilter($im, IMG_FILTER_BRIGHTNESS, 20)) {
   echo 'Image brightness changed.';
   imagepng($im, 'sean.png');
} else {
   echo 'Image brightness change failed.';
}

imagedestroy($im);
?>

Пример 3. imagefilter() colorize example

<?php
$im = imagecreatefrompng('philip.png');

/* R, G, B, so 0, 255, 0 is green */
if ($im && imagefilter($im, IMG_FILTER_COLORIZE, 0, 255, 0)) {
   echo 'Image successfully shaded green.';
   imagepng($im, 'philip.png');
} else {
   echo 'Green shading failed.';
}

imagedestroy($im);
?>



imagefilter
santibari at fibertel dot com
27-Feb-2006 11:37
A colorize algorithm wich preserves color luminosity (i.e black
will output black, and white will output white).
This works in PHP4 and is great for customizing interfaces
dinamically.

<?php
function colorize($img_src,$img_dest, $r, $g, $b)
{
if(!$im = imagecreatefromgif($img_src))
  return "Could not use image $img_src";
  
//We will create a monochromatic palette based on
//the input color
//which will go from black to white
//Input color luminosity: this is equivalent to the
//position of the input color in the monochromatic
//palette
$lum_inp=round(255*($r+$g+$b)/765); //765=255*3

//We fill the palette entry with the input color at its
//corresponding position

$pal[$lum_inp]['r']=$r;
$pal[$lum_inp]['g']=$g;
$pal[$lum_inp]['b']=$b;

//Now we complete the palette, first we'll do it to
//the black,and then to the white.

//FROM input to black
//===================
//how many colors between black and input
$steps_to_black=$lum_inp;       

//The step size for each component
if($steps_to_black)
 {
 $step_size_red=$r/$steps_to_black;   
 $step_size_green=$g/$steps_to_black;   
 $step_size_blue=$b/$steps_to_black;   
 }

for($i=$steps_to_black;$i>=0;$i--)
 {
 $pal[$steps_to_black-$i]['r']=$r-round($step_size_red*$i);
 $pal[$steps_to_black-$i]['g']=$g-round($step_size_green*$i);
 $pal[$steps_to_black-$i]['b']=$b-round($step_size_blue*$i);
 }

//From input to white:
//===================
//how many colors between input and white
$steps_to_white=255-$lum_inp;

if($steps_to_white)
  {
  $step_size_red=(255-$r)/$steps_to_white;   
  $step_size_green=(255-$g)/$steps_to_white;   
  $step_size_blue=(255-$b)/$steps_to_white;   
  }
 else
  $step_size_red=$step_size_green=$step_size_blue=0;

 //The step size for each component
 for($i=($lum_inp+1);$i<=255;$i++)
  {
  $pal[$i]['r']=$r + round($step_size_red*($i-$lum_inp));
  $pal[$i]['g']=$g + round($step_size_green*($i-$lum_inp));
  $pal[$i]['b']=$b + round($step_size_blue*($i-$lum_inp));
  }
//--- End of palette creation

//Now,let's change the original palette into the one we
//created
for($c = 0; $c < $palette_size; $c++)
 {
 $col = imagecolorsforindex($im, $c);         
 $lum_src=round(255*($col['red']+$col['green']
               +$col['blue'])/765);
 $col_out=$pal[$lum_src];
 imagecolorset($im, $c, $col_out['r'],
                               $col_out['g'],
                               $col_out['b']);
 }

 //save the image file
 imagepng($im,$img_dest);
 imagedestroy($im);
}//end function colorize
?>
webmaster at qudi dot de
31-Jan-2006 06:53
for a quick, ok-looking, sepia-effect (also in php4) I just use this little fellow, since a real implementation of sepia was just way too slow.

function pseudosepia(&$im,$percent){
     $sx=imagesx($im);
     $sy=imagesy($im);
     $filter=imagecreatetruecolor($sx,$sy);
     $c=imagecolorallocate($filter,100,50,50);
     imagefilledrectangle($filter,0,0,$sx,$sy,$c);
     imagecopymerge($im,$filter,0,0,0,0,$sx,$sy,$percent);
}
a php user at nowhere dot com
20-Dec-2005 12:48
http://www.hudzilla.org/phpbook/read.php/11_2_15
for more detailed info, and some <i>arg</i> guidelines.
vdepizzol at hotmail dot com
04-Sep-2004 01:36
Examples using imagefilter():

<?php
$im = imagecreatefrompng('dave.png');
if ($im && imagefilter($im, IMG_FILTER_GRAYSCALE)) {
   echo 'Image converted to grayscale.';
   imagepng($im, 'dave.png');
} else {
   echo 'Conversion to grayscale failed.';
}

imagedestroy($im);
?>

/////////////////////////////

<?php
$im = imagecreatefrompng('sean.png');
if ($im && imagefilter($im, IMG_FILTER_BRIGHTNESS, 20)) {
   echo 'Image brightness changed.';
   imagepng($im, 'sean.png');
} else {
   echo 'Image brightness change failed.';
}

imagedestroy($im);
?>

/////////////////////////////

<?php
$im = imagecreatefrompng('philip.png');

/* R, G, B, so 0, 255, 0 is green */
if ($im && imagefilter($im, IMG_FILTER_COLORIZE, 0, 255, 0)) {
   echo 'Image successfully shaded green.';
   imagepng($im, 'philip.png');
} else {
   echo 'Green shading failed.';
}

imagedestroy($im);
?>
kees at tweakers dot net
20-Jul-2004 06:26
From what i have been able to find from this function, it accepts the following arguments:
       IMG_FILTER_NEGATE
       IMG_FILTER_GRAYSCALE
       IMG_FILTER_EDGEDETECT
       IMG_FILTER_GAUSSIAN_BLUR
       IMG_FILTER_SELECTIVE_BLUR
       IMG_FILTER_EMBOSS
       IMG_FILTER_MEAN_REMOVAL

The following arguments need one or more arguments.
       IMG_FILTER_SMOOTH, -1924.124
       IMG_FILTER_COLORIZE, -127.12, -127.98, 127
       IMG_FILTER_CONTRAST, -90
       IMG_FILTER_BRIGHTNESS, 98
      
I haven't tested them all, the names speak for themselves.

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 Last updated: Tue, 15 Nov 2005