PHP 7.2.7 Released

imagecolorset

(PHP 4, PHP 5, PHP 7)

imagecolorset Setzt die Farbe für den angegebenen Paletten-Index

Beschreibung

void imagecolorset ( resource $image , int $index , int $red , int $green , int $blue [, int $alpha = 0 ] )

Hierdurch wird der Farbwert der Palette auf die angegebene Farbe gesetzt. Dies ist nützlich bei Aktionen wie "Fülle Farbe X mit Farbe Y" (Flood-Fill-Effekt) ohne den sonst notwendigen Aufwand für solche Aktionen betreiben zu müssen.

Parameter-Liste

image

Eine von den verschiedenen Erzeugungsfunktionen wie imagecreatetruecolor() gelieferte Grafikressource.

index

Ein Index der Palette.

red

Wert der Rotkomponente.

green

Wert der Grünkomponente.

blue

Wert der Blaukomponente.

alpha

Wert der Alpha-Komponente.

Rückgabewerte

Es wird kein Wert zurückgegeben.

Changelog

Version Beschreibung
5.4.0 Der alpha Parameter wurde hinzugefügt.

Beispiele

Beispiel #1 imagecolorset() Beispiel

<?php
// Erzeuge ein 300x100 Bild
$im imagecreate(300100);

// Setze den Hintergrund auf Rot
imagecolorallocate($im25500);

// Ermittle den Farbindex des Hintergrunds
$bg imagecolorat($im00);

// Setze den Hintergrund auf Blau
imagecolorset($im$bg00255);

// Gib das Bild an den Browser aus
header('Content-Type: image/png');

imagepng($im);
imagedestroy($im);
?>

Siehe auch

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User Contributed Notes 10 notes

up
2
m4551 at abasoft dot it
14 years ago
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, $i);
    }
}
up
2
moxleystratton.com
11 years ago
If you want to convert a Color image to Grayscale without creating a blotchy image, use this color calculation:
<?php
function imagetograyscale($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);
    }
}
?>
up
1
Daniel Klein
2 years ago
If you are creating a palette image from scratch you have to use imagecolorallocate() for each index before you can use imagecolorset() on it.
up
0
Thomas Mueller
10 years ago
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);
    }
}
?>
up
0
heavyraptor2 at hotmail dot com
10 years ago
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
up
0
dade dot c at email dot it
13 years ago
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);
}
up
-1
olivier at moostik dot net
16 years ago
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;

}
up
-1
Bartman
8 years ago
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']);
    }
}
?>
up
-1
admin at phpgfx dot com
10 years ago
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 );
    }
}

?>
up
-2
info at devking dot com
15 years ago
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 );   
}
}
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