php 如何找到图像中的主色？
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How to find the Dominant color in image?
提问by motioz
i want to find the dominant color in image, how can i do it ?
我想找到图像中的主色，我该怎么做？
it would be great if i can get this in HEX code (exm: #eeeeee)
如果我能在十六进制代码中得到这个就太好了（exm：#eeeeee）
采纳答案by tkone
To find the most "dominant" color in an image, meaning the color that is most prevalent in the image: you'd need to create a histogram of the image.
要找到图像中最“主要”的颜色，即图像中最普遍的颜色：您需要创建图像的直方图。
Here is an the code from this article on how to create a histogram in PHP. (Website has gone off line several times)
这是本文中有关如何在 PHP 中创建直方图的代码。（网站已多次下线）
<?php
$source_file = "test_image.jpg";
// histogram options
$maxheight = 300;
$barwidth = 2;
$im = ImageCreateFromJpeg($source_file);
$imgw = imagesx($im);
$imgh = imagesy($im);
// n = total number or pixels
$n = $imgw*$imgh;
$histo = array();
for ($i=0; $i<$imgw; $i++)
{
for ($j=0; $j<$imgh; $j++)
{
// get the rgb value for current pixel
$rgb = ImageColorAt($im, $i, $j);
// extract each value for r, g, b
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
// get the Value from the RGB value
$V = round(($r + $g + $b) / 3);
// add the point to the histogram
$histo[$V] += $V / $n;
}
}
// find the maximum in the histogram in order to display a normated graph
$max = 0;
for ($i=0; $i<255; $i++)
{
if ($histo[$i] > $max)
{
$max = $histo[$i];
}
}
echo "<div style='width: ".(256*$barwidth)."px; border: 1px solid'>";
for ($i=0; $i<255; $i++)
{
$val += $histo[$i];
$h = ( $histo[$i]/$max )*$maxheight;
echo "<img src=\"img.gif\" width=\"".$barwidth."\"
height=\"".$h."\" border=\"0\">";
}
echo "</div>";
?>
In that example $maxis your most "dominant" color.
在那个例子中$max是你最“主导”的颜色。
回答by Zachary Schuessler
There is a PHP class developed that handles this, named color extract. However, know that doing this on the server side will require substantial system resources. You may wish to instead do this with canvas.
开发了一个 PHP 类来处理这个问题，名为color extract。但是，要知道在服务器端执行此操作将需要大量系统资源。您可能希望使用canvas来执行此操作。
回答by user2091347
Try this: http://www.coolphptools.com/color_extract.
试试这个：http: //www.coolphptools.com/color_extract。
The Image Color Extract PHP class pulls the most common colors (in percentages) out of an image file. The color values are in hexadecimal.
Image Color Extract PHP 类从图像文件中提取最常见的颜色（以百分比表示）。颜色值是十六进制的。
回答by Shahroq
In regard to tkone answer, the $max is just a parameter showing density of the color at an image. I would change the code a bit to return the HEX color:
关于 tkone 答案，$max 只是显示图像颜色密度的参数。我会稍微更改代码以返回十六进制颜色：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Empty Document</title>
</head>
<body>
<?php
error_reporting(0);
function rgb2hex($rgb) {
$hex = "#";
$hex .= str_pad(dechex($rgb[0]), 2, "0", STR_PAD_LEFT);
$hex .= str_pad(dechex($rgb[1]), 2, "0", STR_PAD_LEFT);
$hex .= str_pad(dechex($rgb[2]), 2, "0", STR_PAD_LEFT);
return $hex; // returns the hex value including the number sign (#)
}
$source_file = "image.jpg";
// histogram options
$maxheight = 300;
$barwidth = 2;
$im = ImageCreateFromJpeg($source_file);
$imgw = imagesx($im);
$imgh = imagesy($im);
// n = total number or pixels
$n = $imgw*$imgh;
$histo = array();
for ($i=0; $i<$imgw; $i++)
{
for ($j=0; $j<$imgh; $j++)
{
// get the rgb value for current pixel
$rgb = ImageColorAt($im, $i, $j);
//echo $rgb."<br>";
// extract each value for r, g, b
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
// get the Value from the RGB value
$V = round(($r + $g + $b) / 3);
//echo $V."<br>";
// add the point to the histogram
$histo[$V] += $V / $n;
$histo_color[$V] = rgb2hex([$r,$g,$b]);
}
}
// find the maximum in the histogram in order to display a normated graph
$max = 0;
for ($i=0; $i<255; $i++)
{
if ($histo[$i] > $max)
{
$max = $histo[$i];
}
}
echo "<div style='width: ".(256*$barwidth)."px; border: 1px solid'>";
for ($i=0; $i<255; $i++)
{
$val += $histo[$i];
$h = ( $histo[$i]/$max )*$maxheight;
echo "<img src=\"img.gif\" width=\"".$barwidth."\"
height=\"".$h."\" border=\"0\">";
}
echo "</div>";
$key = array_search ($max, $histo);
$col = $histo_color[$key];
?>
<p style="min-width:100px; min-height:100px; background-color:<?php echo $col?>;"></p>
<img src="<?php echo $source_file?>">
</body>
</html>
Also, it is worth mentioning that this is just the most 'repeated' color at the image that cannot absolutely considered 'dominant' color.
此外，值得一提的是，这只是图像中最“重复”的颜色，不能绝对视为“主导”颜色。
回答by Adam F
Sounds like a delightful code to write! I made a function awhile back that goes through every pixel and adds a shade to each one. What you could do is:
听起来像一个令人愉快的代码编写！不久前我做了一个函数，它遍历每个像素并为每个像素添加阴影。你可以做的是：
For Each Pixel, find the highest color (r,g,or b) and do the math ($colorG++ or something)
对于每个像素，找到最高的颜色（r、g 或 b）并进行数学运算（$colorG++ 或其他）
at the end, find out what one is the largest, and there would be your highest rgb shade.
最后，找出最大的那个，然后就会有最高的 rgb 阴影。
I wonder what color would come out if you used the resulting rgb value...
我想知道如果您使用生成的 rgb 值会出现什么颜色...
回答by adilbo
PHP Simple Color Thief
PHP简单的颜色小偷
Detect the Dominant Color used in an Image
检测图像中使用的主色
How it Works
这个怎么运作
PHP:
PHP：
require 'color.php';
$image = 'https://cdn.pixabay.com/photo/2012/11/24/07/43/colorful-67134_960_720.jpg'
$default_color = 'ffffff';
echo simple_color_thief($image, $default_color);
Will return the Hex Color: e0a654
将返回十六进制颜色：e0a654
The color.phpFile:
该color.php文件：
/*
PHP Simple Color Thief
======================
Detect the Dominant Color used in an Image
Copyright 2019 Igor Gaffling
*/
function simple_color_thief($img, $default='eee') {
if(@exif_imagetype($img)) { // CHECK IF IT IS AN IMAGE
$type = getimagesize($img)[2]; // GET TYPE
if ($type === 1) { // GIF
$image = imagecreatefromgif($img);
// IF IMAGE IS TRANSPARENT (alpha=127) RETURN fff FOR WHITE
if (imagecolorsforindex($image, imagecolorstotal($image)-1)['alpha'] == 127) return 'fff';
} else if ($type === 2) { // JPG
$image = imagecreatefromjpeg($img);
} else if ($type === 3) { // PNG
$image = imagecreatefrompng($img);
// IF IMAGE IS TRANSPARENT (alpha=127) RETURN fff FOR WHITE
if ((imagecolorat($image, 0, 0) >> 24) & 0x7F === 127) return 'fff';
} else { // NO CORRECT IMAGE TYPE (GIF, JPG or PNG)
return $default;
}
} else { // NOT AN IMAGE
return $default;
}
$newImg = imagecreatetruecolor(1, 1); // FIND DOMINANT COLOR
imagecopyresampled($newImg, $image, 0,0,0,0,1,1, imagesx($image), imagesy($image));
return dechex(imagecolorat($newImg, 0, 0)); // RETURN HEX COLOR
}
// DEMO
foreach(glob('./*.{jpg,png,gif}', GLOB_BRACE) as $i) {
echo '<div style="width:26%;padding:50px;background:#'.
simple_color_thief($i,'f00').
';display:inline-block"><img style="height:200px" src="'.
$i.'"></div>';
}
回答by Pierre MIchel Agbla
You give an image ressouce as argument.
你给出一个图像资源作为参数。
Ex:
前任：
$im=imagecreatefromjpeg("path/to/image");
getDominantcolor($im);
NB: This function will little bit slow down your page since it will compare each color of the image to all other color to make the statistic. It returns rgb value of the dominant color as array
注意：此功能会稍微减慢您的页面速度，因为它会将图像的每种颜色与所有其他颜色进行比较以进行统计。它将主色的 rgb 值作为数组返回
function getDominantcolor($im){
$width=imagesx($im);
$height=imagesy($im);
$colorArr=[];
$comparArr=[];
$colCount=0;
//fixed height
for ($j=0; $j < $height; $j++) {
//fetching color on widths
for ($i=0; $i < $height; $i++) {
$colorArr[]=imagecolorat ( $im ,$i ,$j );
}
}
//fixed height
for ($col=0; $col < count($colorArr); $col++) {
for ($cel=0; $cel < count($colorArr); $cel++) {
if($colorArr[$col]===$colorArr[$cel]){
$colCount+=1;
}
}
$comparArr[]=$colCount;
$colCount=0;
}
foreach ($comparArr as $key => $value) {
if($value===max($comparArr)){
$max_index=$key;
break;
}
}
$rgb=$colorArr[$max_index];
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
return ['r'=>$r,'g'=>$g,'b'=>$b];
}
回答by afaf12
You should have a look at GD and Image Functions.
你应该看看GD 和 Image Functions。
There is a similar questionon SO about extracting color information from an image with PHP, and it links to this classon github.
回答by Ajeet Lakhani
Though its in javascript but color-thiefis best for getting dominant color in image.
虽然它在 javascript 中，但颜色窃贼最适合在图像中获取主色。
