[PHP] Identify the main color of the picture_PHP tutorial

1. Applicable scenarios: List the corresponding pictures according to color.

2. Main program and API explanation:
[php]

class MajorColor
{
//Reference color
protected $_colors = null;
       
//Tolerance
protected $_tolerance = 80;
       
//Ignored colors
protected $_ignoreColors = array();
       
//Supported image types
protected $_funcs = array('image/png' => 'imagecreatefrompng', 'image/jpeg' => 'imagecreatefromjpeg', 'image/gif' => 'imagecreatefromgif');
       
Public function __construct(array $colors = null) {
If(null !== $colors) {
$this->_colors = $colors;
         } 
}  
       
Public function setColors(array $colors) {
          $this->_colors = $colors;
}  
       
Public function setTolerance($tolerance) {
          $this->_tolerance = $tolerance;
}  
       
Public function setIgnoreColors($colors) {
          $this->_ignoreColors = $colors;
}  
       
Public function _isValidColor($confVal, $val) {
If(is_array($confVal)) {
                 return $val >= $confVal[0] && $val <= $confVal[1];
         } else {
                   return $val >= $confVal - $this->_tolerance && $val <= $confVal + $this->_tolerance;
         } 
}  
       
Public function getOrderedColors($pic) {
$size = getimagesize($pic);
If(!$size) {
              return false;
         } 
                                   
         $width = $size[0];
         $height = $size[1];
         $mime = $size['mime'];
$func = isset($this->_funcs[$mime]) ? $this->_funcs[$mime] : null;
If(!$func) {
              return false;
         } 
                                   
          $im = $func($pic);
If(!$im) {
              return false;
         } 

          $total = $width * $height;
         $nums = array();
for($i = 0; $i < $width; $i++) {
for($m = 0; $m < $height; $m++) {
$color_index = imagecolorat($im, $i, $m);
                     $color_tran = imagecolorsforindex($im, $color_index);
                   $alpha = $color_tran['alpha'];
                unset($color_tran['alpha']); 
                if(100 < $alpha || in_array($color_tran, $this->_ignoreColors)) { 
                    continue; 
                } 
 
                foreach ($this->_colors as $colorid => $color) { 
                    if($this->_isValidColor($color['red'], $color_tran['red']) 
                        && $this->_isValidColor($color['green'], $color_tran['green']) 
                        && $this->_isValidColor($color['blue'], $color_tran['blue']) 
                    ) { 
                        $nums[$colorid] = isset($nums[$colorid]) ? $nums[$colorid] + 1 : 1; 
                    } 
                } 
            } 
        } 
         
        imagedestroy($im); 
        arsort($nums); 
        return $nums; 
    } 
     
    public function getMajorColor($pic) { 
        $nums = $this->getOrderedColors($pic); 
        $keys = array_keys($nums); 
        return $keys[0]; 
    } 
} 
1.void setColors(array $colors)
设置可选颜色，即上图中“全部颜色”下的所有颜色(白、灰、黑...)

2.void setTolerance(int $tolerance)
设置容差，比如绿色的RGB值为(0,255,0)，如果设置容差为40，那么-40<=R<<40 && 215<=G<=295 && -40<=B<=40范围内的所有颜色将被视为绿色。
此方法用于大致区别各颜色。

3.void setIgnoreColors(array $colors)
设置不需考虑的颜色。如大多图片的背景是白色，而我们显然不希望结果是白色，此时可调用此方法简略白色。

4.array getOrderedColors($pic)
根据$pic获取各种颜色(用setColors设置的颜色)的匹配数量，按匹配量由高到低排列
参数$pic是待检测图片的路径

5.mix getMajorColor($pic)
内部调用getOrderedColors，返回匹配量最高的颜色的key

三、$colors的格式及范围确定
1.如果$colors中的各种颜色差别很明显，我们只需简单的传入颜色值，内部会根据setTolerance设置的容差来区别各颜色。
[php] 
$colors = array( 
    1 => array('red' => 0xff, 'green' => 0xff, 'blue' => 0xff), 
    2 => array('red' => 0xc0, 'green' => 0xc0, 'blue' => 0xc0), 
    2 => array('red' => 0x00, 'green' => 0x00, 'blue' => 0x00), 
); 

2. The setTolerance method of setting tolerance can only roughly distinguish various colors. If you need more precise control, you need to set the R, G, and B ranges of a certain color respectively www.2cto.com
[php]
$colors = array(
1 => array('red' => array(189, 230), 'green' => array(189, 230), 'blue' => array(189, 230)),
2 => array('red' => array(0, 37), 'green' => array(0, 37), 'blue' => array(0, 37)),
3 => array('red' => array(128, 255), 'green' => array(0, 76), 'blue' => array(0, 100)),
);
A series of fine-tuning is required until the various colors are clearly distinguishable.
Author: xiaodao1986