imagecolorset

(PHP 4, PHP 5, PHP 7)

imagecolorset — 给指定调色板索引设定颜色

说明

void imagecolorset ( resource $image , int $index , int $red , int $green , int $blue )

本函数将调色板中指定的索引设定为指定的颜色。对于在调色板图像中创建类似区域填充（flood-fill）的效果很有用，免去了真的去填充的开销。

参见 imagecolorat() 。

用户评论:

[#1] Daniel Klein [2015-07-01 13:25:43]

If you are creating a palette image from scratch you have to use imagecolorallocate() for each index before you can use imagecolorset() on it.

[#2] Bartman [2009-08-25 02:12:07]

I had the same problem as heavyraptor2 so i made this function...
<?php function imagecolorize($im,$endcolor){ //funcion takes image and turns black into $endcolor, white to white and //everything in between in corresponding gradient //$endcolor should be 6 char html color //make sure it has usable palette if (imageistruecolor($im)) { imagetruecolortopalette($im, false, 256); } //first make it gray to be sure of even results (thanks moxleystratton.com) //comment this loop if you want the output based on, for example, //the red channel (for this take a look at the $gray-var in the last loop) for ($c = 0; $c < imagecolorstotal($im); $c++) { $col = imagecolorsforindex($im, $c); $gray = round(0.299 * $col['red'] + 0.587 * $col['green'] + 0.114 * $col['blue']); imagecolorset($im, $c, $gray, $gray, $gray); } //determine end-colors in hexdec $EndcolorRGB['r'] = hexdec( substr($endcolor, 0, 2)); $EndcolorRGB['g'] = hexdec( substr($endcolor, 2, 2)); $EndcolorRGB['b'] = hexdec( substr($endcolor, 4, 2)); //determine gradient-delta's $stepR = (255-$EndcolorRGB['r'])/255.0; $stepG = (255-$EndcolorRGB['g'])/255.0; $stepB = (255-$EndcolorRGB['b'])/255.0; //aColor contains the 256 gradations between endcolor(i=0) and white(i=255) $aColor = array(); for ($i = 0; $i<=255; $i++){ $aColor[$i]['r'] = $EndcolorRGB['r'] + ($i*$stepR); $aColor[$i]['g'] = $EndcolorRGB['g'] + ($i*$stepG); $aColor[$i]['b'] = $EndcolorRGB['b'] + ($i*$stepB); } //for every color-index we now replace $gray-values for $aColor for ($c = 0; $c < imagecolorstotal($im); $c++){ $currentColorRGB = imagecolorsforindex($im, $c); $gray = $currentColorRGB['red'];//image is grayscale, so red,green and blue // should be equal. We use this number as key of aColor imagecolorset($im,$c,(int)$aColor[$gray]['r'], (int)$aColor[$gray]['g'], (int)$aColor[$gray]['b']); } }?>

[#3] Thomas Mueller [2008-04-23 10:42:34]

Here is a function to colorize a picture gradient style.

All you have to do is to pass an img-object and an array of colors.

e.g.

$arr = array('#000000', '#990000', '#00FFFF', '#FFFFDD');
colorize ($img, $arr);

<?php function colorize($imgdata, $palette) { imageTrueColorToPalette($imgdata,false,0xFF); $l = count($palette)-1; $i = imagecolorstotal($imgdata); while ($i--) { list($r,$g,$b) = array_values(imageColorsForIndex($imgdata,$i)); $grayscale = ($r*.3 + $g*.59 +$b*.11) / 0xFF; $pos = $l*$grayscale; $perc = $pos-floor($pos); $tbase = str_replace("#", '', $palette[$pos]); $baseR = hexdec(substr($tbase,0,2)); $baseG = hexdec(substr($tbase,2,2)); $baseB = hexdec(substr($tbase,4,2)); $tmix = str_replace("#", '', $palette[$pos+1]); $mixR = hexdec(substr($tmix,0,2)); $mixG = hexdec(substr($tmix,2,2)); $mixB = hexdec(substr($tmix,4,2)); $resR = $baseR+($mixR-$baseR)*$perc; $resG = $baseG+($mixG-$baseG)*$perc; $resB = $baseB+($mixB-$baseB)*$perc; imagecolorset($imgdata, $i, $resR, $resG, $resB); } } ?>

[#4] heavyraptor2 at hotmail dot com [2008-02-20 01:08:33]

I've been looking for a simple function which "colorizes" an image, without any success ... it looks like a lot of people mean something different with "colorizing" an image, because actually colorzing means multiplying the old color's grayscale with the new color. So a white pixel would become 100% of the colorize-to-color and a black pixel would stay black (I know I can't explain well ... I hope you understood, otherwise take a look at the example below the functions' code).

<?php function image_colorize(&$img,$rgb) { imageTrueColorToPalette($img,true,256); $numColors = imageColorsTotal($img); for ($x = 0; $x < $numColors; $x++) { list($r,$g,$b) = array_values(imageColorsForIndex($img,$x)); // calculate grayscale in percent $grayscale = ($r + $g + $b) / 3 / 0xff; imageColorSet($img,$x, $grayscale * $rgb[0], $grayscale * $rgb[1], $grayscale * $rgb[2] ); } return true; } ?>

Example of usage:
<?php $color = array(0xff,0xaa,0x2a); // color to convert to $url = 'http://sundog.net/images/uploads/1_google_logo.jpg'; $img = imageCreateFromJpeg($url); image_colorize($img,$color); header('Content-type: image/gif'); imageGif($img); exit; ?>

Enjoy

[#5] admin at phpgfx dot com [2007-08-25 11:37:47]

Here is a function to turn an image into pure black and white

<?php function imagepurebw( $img, $amount = 383 ) { $total = imagecolorstotal( $img ); for ( $i = 0; $i < $total; $i++ ) { $index = imagecolorsforindex( $img, $i ); array_pop( $index ); $color = ( array_sum( $index ) > $amount ) ? 255 : 0; imagecolorset( $img, $i, $color, $color, $color ); } } ?>

[#6] moxleystratton.com [2006-10-04 15:59:21]

If you want to convert a Color image to Grayscale without creating a blotchy image, use this color calculation:
<?php function imagetograyscale($im) { if (imageistruecolor($im)) { imagetruecolortopalette($im, false, 256); } for ($c = 0; $c < imagecolorstotal($im); $c++) { $col = imagecolorsforindex($im, $c); $gray = round(0.299 * $col['red'] + 0.587 * $col['green'] + 0.114 * $col['blue']); imagecolorset($im, $c, $gray, $gray, $gray); } } ?>

[#7] dade dot c at email dot it [2004-10-02 13:47:29]

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)

{
header("Content-type: image/png");
$im = imagecreatefrompng("images/table.png");

imagetruecolortopalette($im, FALSE, 256);

   for ($c = 0; $c < 64; $c++){
     $col = imagecolorsforindex($im, $c);
imagecolorset ( $im, $c, $r*$col['red']/256, $g*$col['green']/256, $b*$col['blue']/256);
}

imagepng($im);
imagedestroy($im);
}

[#8] m4551 at abasoft dot it [2004-04-23 09:19:41]

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);
}
}

[#9] info at devking dot com [2002-08-08 14:20:29]

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 );
}
}

[#10] olivier at moostik dot net [2001-07-11 17:49:55]

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;

}