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imagecolorset

(PHP 4, PHP 5, PHP 7, PHP 8)

imagecolorset Установка набора цветов для заданного индекса палитры

Описание

imagecolorset(
    GdImage $image,
    int $color,
    int $red,
    int $green,
    int $blue,
    int $alpha = 0
): ?false

Функция устанавливает соответствие индекса в палитре заданному цвету. Это полезно для создания эффекта подобного заливке цветом без осуществления заливки.

Список параметров

image

Объект GdImage, который возвращает одна из функций, создающих изображения, например, imagecreatetruecolor().

color

Индекс в палитре.

red

Значение красного компонента цвета.

green

Значение зелёного компонента цвета.

blue

Значение синего компонента цвета.

alpha

Значение альфа компонента.

Возвращаемые значения

Функция возвращает null в случае успешного выполнения или false в случае ошибки.

Список изменений

Версия Описание
8.0.0 Параметр image теперь ожидает экземпляр класса GdImage; раньше параметр ждал корректный gd-ресурс (resource).

Примеры

Пример #1 Пример использования imagecolorset()

<?php
// Создание изображения размером 300x100
$im = imagecreate(300, 100);

// Установка красного цвета фона
imagecolorallocate($im, 255, 0, 0);

// Получение индекса цвета фона
$bg = imagecolorat($im, 0, 0);

// Установка синего цвета фона
imagecolorset($im, $bg, 0, 0, 255);

// Вывод изображения в браузер
header('Content-Type: image/png');

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

Смотрите также

  • imagecolorat() - Получение индекса цвета пиксела
add a note

User Contributed Notes 10 notes

up
4
moxleystratton.com
17 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
3
heavyraptor2 at hotmail dot com
16 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
2
dade dot c at email dot it
19 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
2
m4551 at abasoft dot it
19 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
1
Thomas Mueller
15 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, $resB);
}
}
?>
up
1
Daniel Klein
8 years ago
If you are creating a palette image from scratch you have to use imagecolorallocate() for each index before you can use imagecolorset() on it.
up
0
Bartman
14 years ago
I had the same problem as heavyraptor2 so i made this function...
<?php
function imagecolorize($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
olivier at moostik dot net
22 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
-2
admin at phpgfx dot com
16 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
21 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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