imagecolorresolvealpha
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);
}
}
?>
imagecolorset
(PHP 4, PHP 5)
imagecolorset — Establece el color para el índice de la paleta especificado
Descripción
void imagecolorset
( resource $im
, int $index
, int $red
, int $green
, int $blue
)
Establece el índice especificado de la paleta con el color introducido. Esto es útil para crear efectos de rellenado en imagenes con paletas sin la sobrecarga de tener que realizar el rellenado.
Vea también imagecolorat().
add a note
User Contributed Notesimagecolorset
Thomas Mueller
23-Apr-2008 07:42
23-Apr-2008 07:42
heavyraptor2 at hotmail dot com
20-Feb-2008 10:08
20-Feb-2008 10:08
I've been looking for a simple function which "colorizes" an image, without any success ... it looks like a lot of people mean something different with "colorizing" an image, because actually colorzing means multiplying the old color's grayscale with the new color. So a white pixel would become 100% of the colorize-to-color and a black pixel would stay black (I know I can't explain well ... I hope you understood, otherwise take a look at the example below the functions' code).
<?php
function image_colorize(&$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
admin at phpgfx dot com
25-Aug-2007 08:37
25-Aug-2007 08:37
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, $color );
}
}
?>
moxleystratton.com
05-Oct-2006 12:59
05-Oct-2006 12:59
If you want to convert a Color image to Grayscale without creating a blotchy image, use this color calculation:
<?php
function imagetograyscale($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, $gray);
}
}
?>
dade dot c at email dot it
02-Oct-2004 10:47
02-Oct-2004 10:47
this is helpful if you would like to implement a color theme system in your website... try it out
Davide Candiloro Italy
function colorize ($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
23-Apr-2004 06:19
23-Apr-2004 06:19
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, $i);
}
}
info at devking dot com
08-Aug-2002 11:20
08-Aug-2002 11:20
here's a simple function to greyscale an image...
function imagecolorgrey( &$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, $t );
}
}
olivier at moostik dot net
12-Jul-2001 02:49
12-Jul-2001 02:49
This function change colors of an image with ranges 0>100 for each primary color:
int ImageSelectiveColor (int im, int red, int green, int blue)
im is image pointer
red, green and blue are ranges 0->100
function ImageSelectiveColor($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;
}