Detect main colors in an image with PHP
I am trying to replicate the functionality that Dribbble.com does with detecting the predominant colors in an Image. In the image below you can see a screenshot from Dribbble.com that shows the 8 predominant colors in the image to the left. Here is the actual page in the image http://dribbble.com/shots/528033-Fresh-Easy?list=following
I need to be able to do this in PHP, once I get the colors I need I will save them to a database so the processing does not need to be run on every page load.
After some research on how to get these colors out of an Image, some people said you simply examine an image pixel by pixel and then save the colors that occur the most. Other say there is more to it and that getting the colors that exist the most frequent won't give the desired affect. They say you need to Quantize the image/colors (I am lost at this point).
In the image below the Dribble shot below is a Javascript library that does the same thing, that page can be viewed here http://lokeshdhakar.com/projects/color-thief/
Viewing the source of that page I can see there is a Javascript file named quantize.js and the results are really good. So I am hoping to be able to do what that Javascript library does but with PHP and GD/ImageMagick
I had found this function that will return the colors and count in an Image with PHP but the results are different from the Javascript version above and the Dribble results
/**
* Returns the colors of the image in an array, ordered in descending order, where the keys are the colors, and the values are the count of the color.
*
* @return array
*/
function Get_Color()
{
if (isset($this->image))
{
$PREVIEW_WIDTH = 150; //WE HAVE TO RESIZE THE IMAGE, BECAUSE WE ONLY NEED THE MOST SIGNIFICANT COLORS.
$PREVIEW_HEIGHT = 150;
$size = GetImageSize($this->image);
$scale=1;
if ($size[0]>0)
$scale = min($PREVIEW_WIDTH/$size[0], $PREVIEW_HEIGHT/$size[1]);
if ($scale < 1)
{
$width = floor($scale*$size[0]);
$height = floor($scale*$size[1]);
}
else
{
$width = $size[0];
$height = $size[1];
}
$image_resized = imagecreatetruecolor($width, $height);
if ($size[2]==1)
$image_orig=imagecreatefromgif($this->image);
if ($size[2]==2)
$image_orig=imagecreatefromjpeg($this->image);
if ($size[2]==3)
$image_orig=imagecreatefrompng($this->image);
imagecopyresampled($image_resized, $image_orig, 0, 0, 0, 0, $width, $height, $size[0], $size[1]); //WE NEED NEAREST NEIGHBOR RESIZING, BECAUSE IT DOESN'T ALTER THE COLORS
$im = $image_resized;
$imgWidth = imagesx($im);
$imgHeight = imagesy($im);
for ($y=0; $y < $imgHeight; $y++)
{
for ($x=0; $x < $imgWidth; $x++)
{
$index = imagecolorat($im,$x,$y);
$Colors = imagecolorsforindex($im,$index);
$Colors['red']=intval((($Colors['red'])+15)/32)*32; //ROUND THE COLORS, TO REDUCE THE NUMBER OF COLORS, SO THE WON'T BE ANY NEARLY DUPLICATE COLORS!
$Colors['green']=intval((($Colors['green'])+15)/32)*32;
$Colors['blue']=intval((($Colors['blue'])+15)/32)*32;
if ($Colors['red']>=256)
$Colors['red']=240;
if ($Colors['green']>=256)
$Colors['green']=240;
if ($Colors['blue']>=256)
$Colors['blue']=240;
$hexarray[]=substr("0".dechex($Colors['red']),-2).substr("0".dechex($Colors['green']),-2).substr("0".dechex($Colors['blue']),-2);
}
}
$hexarray=array_count_values($hexarray);
natsort($hexarray);
$hexarray=array_reverse($hexarray,true);
return $hexarray;
}
else die("You must enter a filename! (\$image parameter)");
}
So I am asking if anyone knows how I can do such a task with PHP? Possibly something exist already that you know of or any tips to put me a step closer to doing this would be appreciated
Solution 1:
Here's exactly what you're looking for in PHP: https://github.com/thephpleague/color-extractor
Example :
use League\ColorExtractor\Palette;
$palette = Palette::fromFilename('some/image.png');
$topEightColors = $palette->getMostUsedColors(8);
Solution 2:
This is my simple method to get the main color of an image
$image=imagecreatefromjpeg('image.jpg');
$thumb=imagecreatetruecolor(1,1);
imagecopyresampled($thumb,$image,0,0,0,0,1,1,imagesx($image),imagesy($image));
$mainColor=strtoupper(dechex(imagecolorat($thumb,0,0)));
echo $mainColor;
Solution 3:
You need to scale down the picture and you will get the main colors of the picture. If you need 4 colors in the pallet, scale it down to about 8x8, 6 colors to about 12x8 and so on...
imagecopyresized for scaled down image then check every pixels and store them in array imagecolorat($image,px,py)
Try this out
<?php
// EXAMPLE PICTURE
$url='https://www.nordoff-robbins.org.uk/sites/default/files/google.jpg';
//var_dump(getColorPallet($url));
echoColors(getColorPallet($url));
function echoColors($pallet){ // OUTPUT COLORSBAR
foreach ($pallet as $key=>$val)
echo '<div style="display:inline-block;width:50px;height:20px;background:#'.$val.'"> </div>';
}
function getColorPallet($imageURL, $palletSize=[16,8]){ // GET PALLET FROM IMAGE PLAY WITH INPUT PALLET SIZE
// SIMPLE CHECK INPUT VALUES
if(!$imageURL) return false;
// IN THIS EXEMPLE WE CREATE PALLET FROM JPG IMAGE
$img = imagecreatefromjpeg($imageURL);
// SCALE DOWN IMAGE
$imgSizes=getimagesize($imageURL);
$resizedImg=imagecreatetruecolor($palletSize[0],$palletSize[1]);
imagecopyresized($resizedImg, $img , 0, 0 , 0, 0, $palletSize[0], $palletSize[1], $imgSizes[0], $imgSizes[1]);
imagedestroy($img);
//CHECK IMAGE
/*header("Content-type: image/png");
imagepng($resizedImg);
die();*/
//GET COLORS IN ARRAY
$colors=[];
for($i=0;$i<$palletSize[1];$i++)
for($j=0;$j<$palletSize[0];$j++)
$colors[]=dechex(imagecolorat($resizedImg,$j,$i));
imagedestroy($resizedImg);
//REMOVE DUPLICATES
$colors= array_unique($colors);
return $colors;
}
?>
Works perfect for me.