imagecolorset

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dade dot c at email dot it
03-Oct-2004 04:47


this is helpful if you would like to implement a color theme system in your website... try it out

Davide Candiloro Italy



function colorize ($pngpath, $r, $g, $b) 

/*

REQUIRES: $pngpath to be a valid path of a greyscale PNG-8 image with 64 colors palette

          $r, $g, $b to be integers in the range 0..255

EFFECTS: returns the png image colorized with the color represented by $r, $g, $b.

*/

{

    header("Content-type: image/png");

    $im = imagecreatefrompng("images/table.png");



    imagetruecolortopalette($im, FALSE, 256); 

   

      for ($c = 0; $c < 64; $c++){ /*64 is the number of colors in the PNG-8 palette*/

        $col = imagecolorsforindex($im, $c);           

        imagecolorset ( $im, $c, $r*$col['red']/256, $g*$col['green']/256, $b*$col['blue']/256); /*replaces original greyscale palette with a colorized one*/

     }



    imagepng($im);

    imagedestroy($im);

}

m4551 at abasoft dot it
24-Apr-2004 12:19


here's a function to greyscale an image even from a truecolor source (jpeg or png).



slightly poor quality, but very fast...



function imagegreyscale(&$img, $dither=1) {    

    if (!($t = imagecolorstotal($img))) {

        $t = 256;

        imagetruecolortopalette($img, $dither, $t);    

    }

    for ($c = 0; $c < $t; $c++) {    

        $col = imagecolorsforindex($img, $c);

        $min = min($col['red'],$col['green'],$col['blue']);

        $max = max($col['red'],$col['green'],$col['blue']);

        $i = ($max+$min)/2;

        imagecolorset($img, $c, $i, $i, $i);

    }

}

info at devking dot com
09-Aug-2002 05:20


here's a simple function to greyscale an image...



function imagecolorgrey( &$img ) {

 for( $i=0; $i<imagecolorstotal( $img ); $i++ ) {

  $c = ImageColorsForIndex( $img, $i );

  $t = ($c["red"]+$c["green"]+$c["blue"])/3;

  imagecolorset( $img, $i, $t, $t, $t );    

 }

}

olivier at moostik dot net
12-Jul-2001 08:49


This function change colors of an image with ranges 0>100 for each primary color:





int ImageSelectiveColor (int im, int red, int green, int blue)





im is image pointer


red, green and blue are ranges 0->100





function ImageSelectiveColor($im,$red,$green,$blue)


 {


  for($i=0;$i<imagecolorstotal($im);$i++)


   {


    $col=ImageColorsForIndex($im,$i);


    $red_set=$red/100*$col['red'];


    $green_set=$green/100*$col['green'];


    $blue_set=$blue/100*$col['blue'];


    if($red_set>255)$red_set=255;


    if($green_set>255)$green_set=255;


    if($blue_set>255)$blue_set=255;


    imagecolorset($im,$i,$red_set,$green_set,$blue_set);


    


   }


  return $im;


 


 }

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