How do you assign a hexadecimal number as the value to a variable in php?

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

hexdec — Hexadecimal to decimal

Description

hexdec(string $hex_string): int|float

hexdec() will ignore any non-hexadecimal characters it encounters. As of PHP 7.4.0 supplying any invalid characters is deprecated.

Parameters

The hexadecimal string to convert

Return Values

The decimal representation of hex_string

Changelog

Examples

Example #1 hexdec() example

var_dump(hexdec("See"));
var_dump(hexdec("ee"));
// both print "int(238)"var_dump(hexdec("that")); // print "int(10)"
var_dump(hexdec("a0")); // print "int(160)"
?>

Notes

Note:

The function can convert numbers that are too large to fit into the platforms int type, larger values are returned as float in that case.

See Also

• dechex() - Decimal to hexadecimal
• bindec() - Binary to decimal
• octdec() - Octal to decimal
• base_convert() - Convert a number between arbitrary bases

hafees at msn dot com ¶

12 years ago

Use this function to convert a hexa decimal color code to its RGB equivalent. Unlike many other functions provided here, it will work correctly with hex color short hand notation.

Also, if a proper hexa decimal color value is given (6 digits), it uses bit wise operations for faster results.

For eg: #FFF and #FFFFFF will produce the same result

/**
* Convert a hexa decimal color code to its RGB equivalent
*
* @param string $hexStr (hexadecimal color value)
* @param boolean $returnAsString (if set true, returns the value separated by the separator character. Otherwise returns associative array)
* @param string $seperator (to separate RGB values. Applicable only if second parameter is true.)
* @return array or string (depending on second parameter. Returns False if invalid hex color value)
*/                                                                                                
function hex2RGB($hexStr, $returnAsString = false, $seperator = ',') {
    $hexStr = preg_replace("/[^0-9A-Fa-f]/", '', $hexStr); // Gets a proper hex string
    $rgbArray = array();
    if (strlen($hexStr) == 6) { //If a proper hex code, convert using bitwise operation. No overhead... faster
        $colorVal = hexdec($hexStr);
        $rgbArray['red'] = 0xFF & ($colorVal >> 0x10);
        $rgbArray['green'] = 0xFF & ($colorVal >> 0x8);
        $rgbArray['blue'] = 0xFF & $colorVal;
    } elseif (strlen($hexStr) == 3) { //if shorthand notation, need some string manipulations
        $rgbArray['red'] = hexdec(str_repeat(substr($hexStr, 0, 1), 2));
        $rgbArray['green'] = hexdec(str_repeat(substr($hexStr, 1, 1), 2));
        $rgbArray['blue'] = hexdec(str_repeat(substr($hexStr, 2, 1), 2));
    } else {
        return false; //Invalid hex color code
    }
    return $returnAsString ? implode($seperator, $rgbArray) : $rgbArray; // returns the rgb string or the associative array
} ?>

OUTPUT:

hex2RGB("#FF0") -> array( red =>255, green => 255, blue => 0)
hex2RGB("#FFFF00) -> Same as above
hex2RGB("#FF0", true) -> 255,255,0
hex2RGB("#FF0", true, ":") -> 255:255:0

programacion at mundosica dot com ¶

10 years ago

Here is other function to transform a MAC Address to decimal:

function get_mac_decimal($mac) {
    $clear_mac = preg_replace('/[^0-9A-F]/i','',$mac);
    $mac_decimal = array();
    for ($i = 0; $i < strlen($clear_mac); $i += 2 ):
        $mac_decimal[] = hexdec(substr($clear_mac, $i, 2));
    endfor;
    return implode('.',$mac_decimal);
}
?>

flurinj at gmx dot net ¶

12 years ago

Here My version of converting a hex string to a signed decimal value:

function hexdecs($hex)
{
    // ignore non hex characters
    $hex = preg_replace('/[^0-9A-Fa-f]/', '', $hex);// converted decimal value:
    $dec = hexdec($hex);// maximum decimal value based on length of hex + 1:
    //   number of bits in hex number is 8 bits for each 2 hex -> max = 2^n
    //   use 'pow(2,n)' since '1 << n' is only for integers and therefore limited to integer size.
    $max = pow(2, 4 * (strlen($hex) + (strlen($hex) % 2)));// complement = maximum - converted hex:
    $_dec = $max - $dec;// if dec value is larger than its complement we have a negative value (first bit is set)
    return $dec > $_dec ? -$_dec : $dec;
}?>

brian at sagesport dot com ¶

17 years ago

The issue I've seen with the existing hex to dec conversion routines is the lack of error-trapping.  I stick to the theory that one should try to cover ALL the bases when writing a generalized routine such as this one.  I have a varied background that covers a wide variety of design/development languages, on the web as well as desktop apps.  As such I've seen multiple formats for writing hex colors.

For example, the color red COULD be written as follows:
#ff0000
&Hff0000
#ff
&Hff

Therefore I have written a function that is case-insensitive and takes into account the chance that different developers have a tendency to format hex colors in different ways.

  function convert_color($hex){
    $len = strlen($hex);
    $chars = array("#","&","H","h");
    $hex = strip_chars($hex, $chars);
    preg_match("/([0-9]|[A-F]|[a-f]){".$len."}/i",$hex,$arr);
    $hex = $arr[0];
    if ($hex) {
      switch($len) {
        case 2:
          $red = hexdec($hex);
          $green = 0;
          $blue = 0;
          break;
        case 4:
          $red = hexdec(substr($hex,0,2));
          $green=hexdec(substr($hex,2,2));
          $blue = 0;
          break;
        case 6:
          $red = hexdec(substr($hex,0,2));
          $green=hexdec(substr($hex,2,2));
          $blue = hexdec(substr($hex,4,2));
          break;      
      };
      $color[success] = true;
      $color[r] = $red;
      $color[g] = $green;
      $color[b] = $blue;
      return $color;
    } else {
      $color[success] = false;
      $color[error] = "unable to convert hex to dec";
    };
  }

  function

chuckySTAR ¶

13 years ago

Here's my hexdec function for greater numbers using BC Math

function bchexdec($hex)
{
    $len = strlen($hex);
    for ($i = 1; $i <= $len; $i++)
        $dec = bcadd($dec, bcmul(strval(hexdec($hex[$i - 1])), bcpow('16', strval($len - $i))));

        return

k10206 at naver dot com ¶

14 years ago

function hexrgb($hexstr) {
    $int = hexdec($hexstr);

    return array("red" => 0xFF & ($int >> 0x10), "green" => 0xFF & ($int >> 0x8), "blue" => 0xFF & $int);
}
?>

Halit YEL - halityesil at globya dot net ¶

12 years ago

RGB to Hex
Hex to RGB
Function

function rgb2hex2rgb($c){
   if(!$c) return false;
   $c = trim($c);
   $out = false;
  if(preg_match("/^[0-9ABCDEFabcdef\#]+$/i", $c)){
      $c = str_replace('#','', $c);
      $l = strlen($c) == 3 ? 1 : (strlen($c) == 6 ? 2 : false);

      if(

Anonymous ¶

17 years ago

I wondered long time what is the best way to generate RGB-color from HEX-color, and just now i found the simpliest way!

$hex = "FF00FF";
$rgb = hexdec($hex); // 16711935
?>

I hope this will save your time! :)

Walter Wlodarski ¶

14 years ago

One of my favourite, multi-purpose, bidirectional solution I wrote many years ago:

function bgr2rgb($cr) {  // bidirectional
    return (($cr & 0x0000FF) << 16 | ($cr & 0x00FF00) | ($cr & 0xFF0000) >> 16);
}

Which you might want to use as :

function hex2cr($hex) {  // strips any leading characters, like #
    return bgr2rgb(hexdec($hex));
}

function cr2hex($cr) { // the usual HTML format, #rrggbb
    return '#'.str_pad(strtoupper(dechex(bgr2rgb($cr))), 6, '0', STR_PAD_LEFT);
}

And, if like me you tend to mistype function names, the synonym :

function rgb2bgr($val) { return bgr2rgb($val); }

sneskid at hotmail dot com ¶

10 years ago

If you want to create or parse signed Hex strings:

// $d should be an int
function sdechex($d) { return ($d<0) ? ('-' . dechex(-$d)) : dechex($d); }// $h should be a string
function shexdec($h) { return ($h[0] === '-') ? -('0x' . substr($h,1) + 0) : ('0x' . $h + 0); }// test
$h = sdechex(-123); // string(3) "-7b"
$d = shexdec($h);   // int(-123)
var_dump($h, $d);
?>

Also note that ('0x' . $hexstr + 0) is faster than hexdec()
(Tested on PHP v5.2.17)

jose dot rob dot jr at gmail dot com ¶

13 years ago

I made these functions to pack up to 64 ID's into a mysql unsigned bigint.

ID's cannot repeat, must be <= bit's limit and > 0.

The functions uses php 32 bit's int as unsigned because we don't actually read the number, just the bits. Then 0xFFFFFFFF display -1 but the bit's are there (tested with linux 2.6 i686 and x86_64)

---

This is an other way to make hex to bin conversions:

function hexbin($hex, $padding = false)
{
    // Validation
    $hex = preg_replace('/^(0x|X)?/i', '', $hex);
    $hex = preg_replace('/[[:blank:]]/', '', $hex);
    if(empty($hex))
    {
        $hex = '0';
    }
    if(!preg_match('/^[0-9A-F]*$/i', $hex))
    {
        trigger_error('Argument is not a hex', E_USER_WARNING);
        return false;
    } // Conversion
    $bin = '';
    $hex = array_reverse(str_split($hex));
    foreach($hex as $n)
    {
        $n = hexdec($n);
        for($i = 1; $i <= 8; $i <<= 1)
        {
            $bin .= ($i & $n)? '1' : '0';
        }
        if($padding)
        {
            $bin .= ' ';
        }
    }
    return ltrim(strrev($bin));
} // Tests
echo "Debug:

";
// Randomly choosed padded number

var_dump(hexbin('00FF FF8F 7F3F FF1F', true));

// string(79) "0000 0000 1111 1111 1111 1111 1000 1111 0111 1111 0011 1111 1111 1111 0001 1111"

// Yellow RGB
var_dump(hexbin('0xF8F800'));

// string(24) "111110001111100000000000"

// Green RGB (padded)
var_dump(hexbin('0x008800', true));

//string(29) "0000 0000 1000 1000 0000 0000"
die("\n
debug");
?>



Have fun ;D

 Ultimater at gmail dot com ¶
13 years ago

hexdec doesn't accept numbers following the period.
What if you have a number like c20.db18?
function floatinghexdec($str)
{
    list($intgr,$hex)=explode('.',$str,2);
    $intgr=ereg_replace("[^A-Fa-f0-9]", "", $intgr);
    $hex=ereg_replace("[^A-Fa-f0-9]", "", $hex);
    $answer=0;
    for($i=0;$i < strlen($hex); $i++)
    {
        $digit=hexdec(substr($hex,$i,1))/16;   // .f is 15/16 because in decimal .9 is 9/10
        $answer += $digit/pow(16,$i);
    }
return hexdec($intgr)+$answer;
}
echo 
floatinghexdec("ff.ff");//255.99609375
?>

helpmedalph at gmail dot com ¶
6 years ago

function hex2rgb($hex) {
    if ($hex[0]=='#') $hex = substr($hex,1);
    if (strlen($hex)==3){
        $hex = $hex[0].$hex[0].$hex[1].$hex[1].$hex[2].$hex[2];
    }
    $int = hexdec($hex);
    return array("red" => 0xFF & ($int >> 0x10), "green" => 0xFF & ($int >> 0x8), "blue" => 0xFF & $int);
}
 chrism at four dot net ¶
20 years
ago

hexdec from 4.1.0 onwards does not show

the same size limitation and therefore

works differently with large numbers than previous php versions.

To obtain the same results, use:




(int) hexdec (...)

 joquius at kakugo dot com ¶
14 years ago

Help a hex-stricken string get back to normal:

$str = preg_replace_callback ("/%([a-zA-Z0-9]{2})/", create_function ('$matches', 'return chr (hexdec ($matches[1]));'), $str);

?>


Anonymous ¶
14 years ago

// Função GET Cor Hexadecima e Retorna em RGB
function hexrgb($hexstr, $rgb) {
 $int = hexdec($hexstr);
 switch($rgb) {
        case "r":
        return 0xFF & $int >> 0x10;
            break;
        case "g":
        return 0xFF & ($int >> 0x8);
            break;
        case "b":
        return 0xFF & $int;
            break;
        default:
        return array(
            "r" => 0xFF & $int >> 0x10,
            "g" => 0xFF & ($int >> 0x8),
            "b" => 0xFF & $int
            );
            break;
    }    
}// END GET Cor Hex => RGB
//Uso
 echo hexrgb("1a2b3c", r); // 26
 echo hexrgb("1a2b3c", g); // 43
 echo hexrgb("1a2b3c", b); // 60
//ou
var_dump(hexrgb("1a2b3c", rgb)); //array(3) { ["r"]=>  int(26) ["g"]=>  int(43) ["b"]=>  int(60) }

 Manithu ¶
15 years ago

This tiny function will return foreground colors (either black or white) in contrast to the color you provide:
function getContrastColor($color)
{
    return (hexdec($color) > 0xffffff/2) ? '000000' : 'ffffff';
}?>

This function will return the opposite (negative):
function negativeColor($color)
{
    //get red, green and blue
    $r = substr($color, 0, 2);
    $g = substr($color, 2, 2);
    $b = substr($color, 4, 2);//revert them, they are decimal now
    $r = 0xff-hexdec($r);
    $g = 0xff-hexdec($g);
    $b = 0xff-hexdec($b);//now convert them to hex and return.
    return dechex($r).dechex($g).dechex($b);
}?>

 cgarvis at gmail dot com ¶
15 years ago

Here is my version of hex2rgb for web colors to 24bit colors.
function hex2rgb_webcolors($hex) {
    $hex = eregi_replace("[^a-fA-F0-9]", "", $hex); 
    switch( strlen($hex) ) {
        case 2:
            $hex = substr($hex,0,2)."0000";
            break;
        case 3:
            $hex = substr($hex,0,1).substr($hex,0,1)
            .substr($hex,1,1).substr($hex,1,1)
            .substr($hex,2,1).substr($hex,2,1);
            break;
        case 4:
            $hex = substr($hex,0,4)."00";
            break;
        case 6:
            break;
        default:
            $hex = 0;
            break;
    }
    return hexdec($hex);
}
?>

 repley at
freemail dot it ¶
16 years ago

From color to color to ...... to color with fade effect. Good for dynamic bar chart.
//MultiColorFade(array hex-colors, int steps)
function MultiColorFade($hex_array, $steps) {$tot = count($hex_array);
$gradient = array();
$fixend = 2;
$passages = $tot-1;
$stepsforpassage = floor($steps/$passages);
$stepsremain = $steps - ($stepsforpassage*$passages);
   for(
$pointer = 0; $pointer < $tot-1 ; $pointer++) {$hexstart = $hex_array[$pointer];
       $hexend = $hex_array[$pointer + 1];
       if($stepsremain > 0){
           if($stepsremain--){
               $stepsforthis = $stepsforpassage + 1;
           }
       }else{
           $stepsforthis = $stepsforpassage;
       }
           if($pointer > 0){
           $fixend = 1;         
       }$start['r'] = hexdec(substr($hexstart, 0, 2));
       $start['g'] = hexdec(substr($hexstart, 2, 2));
       $start['b'] = hexdec(substr($hexstart, 4, 2));$end['r'] = hexdec(substr($hexend, 0, 2));
       $end['g'] = hexdec(substr($hexend, 2, 2));
       $end['b'] = hexdec(substr($hexend, 4, 2));$step['r'] = ($start['r'] - $end['r']) / ($stepsforthis);
       $step['g'] = ($start['g'] - $end['g']) / ($stepsforthis);
       $step['b'] = ($start['b'] - $end['b']) / ($stepsforthis);
           for($i = 0; $i <= $stepsforthis-$fixend; $i++) {$rgb['r'] = floor($start['r'] - ($step['r'] * $i));
           $rgb['g'] = floor($start['g'] - ($step['g'] * $i));
           $rgb['b'] = floor($start['b'] - ($step['b'] * $i));$hex['r'] = sprintf('%02x', ($rgb['r']));
           $hex['g'] = sprintf('%02x', ($rgb['g']));
           $hex['b'] = sprintf('%02x', ($rgb['b']));$gradient[] = strtoupper(implode(NULL, $hex));
       }
   }$gradient[] = $hex_array[$tot-1];
 return $gradient;
}
//end MultiColorFade()
//start test$multi_hex_array = array();
$multi_hex_array[] = array('FF0000','FFFF00');
$multi_hex_array[] = array('FF0000','FFFF00','00FF00');
$multi_hex_array[] = array('FF0000','FFFF00','00FF00','00FFFF');
$multi_hex_array[] = array('FF0000','FFFF00','00FF00','00FFFF','0000FF');
$multi_hex_array[] = array('FF0000','FFFF00','00FF00','00FFFF','0000FF','000000');
$multi_hex_array[] = array('FF0000','FFFF00','00FF00','00FFFF','0000FF','000000','FFFFFF');
foreach($multi_hex_array as $hex_array){$totcolors = count($hex_array);
   $steps = 44;$a = MultiColorFade($hex_array, $steps);
   $tot = count($a);$table = '' . "\n";
   for ($i = 0; $i < $tot; $i++){
       $table .= ' ' . "\n";
   }$table .= '
' . ($i+1) .'
' . $a[$i] . '


';
    echo '
Demanded steps = ' . $steps . '
';
   echo 'Returned steps = ' . $tot;
    if($steps == $tot){
       echo '
OK.' . $steps . ' = ' . $tot . '
';
   }else{
       echo '
FAILED! Demanded steps and returned steps are NOT equal!: ' . $steps . ' != ' . $tot . '
';
   }
   echo $table;
 }//end test
?>

Repley.

 cory at lavacube dot com ¶
16 years ago

A handy little function to convert HEX colour codes to "web safe" colours...
function color_mkwebsafe ( $in )
{
   // put values into an easy-to-use array
   $vals['r'] = hexdec( substr($in, 0, 2) );
   $vals['g'] = hexdec( substr($in, 2, 2) );
   $vals['b'] = hexdec( substr($in, 4, 2) );// loop through
   foreach( $vals as $val )
   {
       // convert value
       $val = ( round($val/51) * 51 );
       // convert to HEX
       $out .= str_pad(dechex($val), 2, '0', STR_PAD_LEFT);
   }
   return 
$out;
}?>

Example: color_mkwebsafe('0e5c94');
Produces: 006699
Hope this helps someone out... Happy coding. :-)
 detrate at hotmail dot com ¶
16 years ago

I made this for a little phpbb mod.  It was used to take the hex value from the database and make a color 20 (in decimal) less, resulting a darker color.
EXAMPLE: #336699 to #1f5285
$row1 
= "336699"; // color
$c = 20;          // difference value$rgb = array(substr($row1,0,2), substr($row1,2,2), substr($row1,4,2));
for($i=0; $i < 3; $i++)
{
  if((hexdec($rgb[$i])-$c) >= 0)
  {
   $rgb[$i] = hexdec($rgb[$i])-$c;$rgb[$i] = dechex($rgb[$i]);
    if(hexdec($rgb[0]) <= 9)
     $rgb[$i] = "0".$rgb[$i];
  } else {
    $rgb[$i] = "00";
  }
}$row2 = $rgb[0].$rgb[1].$rgb[2];?>

 Gabriel
Reguly ¶
17 years ago

After esnhexdec from "rledger at gmail dot com",  the esndechex:
    function esndechex($dec){
         $a = strtoupper(dechex(substr($dec, 1,  2)));
         $b = strtoupper(dechex(substr($dec, 3, 10)));
         return $a . $b;
    }
?>

 bishop ¶
17 years ago

Bullet-proof hex-to-rgb colour converter like brian at sagesport dot com wanted, just far fewer code lines. As a bonus, gives you the ability to return as string or array:
    function &hex2rgb($hex, $asString = true) 
    {
        // strip off any leading #
        if (0 === strpos($hex, '#')) { 
            $hex = substr($hex, 1);
        } else if (0 === strpos($hex, '&H')) {
            $hex = substr($hex, 2);
        }       // break into hex 3-tuple
        $cutpoint = ceil(strlen($hex) / 2)-1; 
        $rgb = explode(':', wordwrap($hex, $cutpoint, ':', $cutpoint), 3);// convert each tuple to decimal
        $rgb[0] = (isset($rgb[0]) ? hexdec($rgb[0]) : 0);
        $rgb[1] = (isset($rgb[1]) ? hexdec($rgb[1]) : 0);
        $rgb[2] = (isset($rgb[2]) ? hexdec($rgb[2]) : 0);
        return (
$asString ? "{$rgb[0]} {$rgb[1]} {$rgb[2]}" : $rgb);
    }
?>

Handles 2, 3, and 6 character colour codes with leading # or &H.





 zubfatal, root at it dot dk ¶
17 years ago

This replaces my previous class.
I've added a few more input checks in the rgb2hex function.
Also it returned incorrect hex values for 1-digit values.
color::rgb2hex(array(0,0,0)) would output 000 not 00000.
/** 
* Convert colors 
* 
* Usage: 
*  color::hex2rgb("FFFFFF") 
*  color::rgb2hex(array(171,37,37)) 
* 
* @author      Tim Johannessen <> 
* @version     1.0.1 
*/ class color { /** 
     * Convert HEX colorcode to an array of colors. 
     * @return      array        Returns the array of colors as array(red,green,blue) 
     */ function hex2rgb($hexVal = "") { 
        $hexVal = eregi_replace("[^a-fA-F0-9]", "", $hexVal); 
        if (strlen($hexVal) != 6) { return "ERR: Incorrect colorcode, expecting 6 chars (a-f, 0-9)"; } 
        $arrTmp = explode(" ", chunk_split($hexVal, 2, " ")); 
        $arrTmp = array_map("hexdec", $arrTmp); 
        return array("red" => $arrTmp[0], "green" => $arrTmp[1], "blue" => $arrTmp[2]); 
    } /** 
     * Convert RGB colors to HEX colorcode 
     * @return      string        Returns the converted colors as a 6 digit colorcode 
     */ 
    function rgb2hex($arrColors = null) { 
        if (!is_array($arrColors)) { return "ERR: Invalid input, expecting an array of colors"; } 
        if (count($arrColors) < 3) { return "ERR: Invalid input, array too small (3)"; } array_splice($arrColors, 3); 
                 for (
$x = 0; $x < count($arrColors); $x++) { 
            if (strlen($arrColors[$x]) < 1) { 
                return "ERR: One or more empty values found, expecting array with 3 values"; 
            } 
                         elseif (eregi("[^0-9]", $arrColors[$x])) { 
                return "ERR: One or more non-numeric values found."; 
            } 
                         else { 
                if ((intval($arrColors[$x]) < 0) || (intval($arrColors[$x]) > 255)) { 
                    return "ERR: Range mismatch in one or more values (0-255)"; 
                } 
                                 else { $arrColors[$x] = strtoupper(str_pad(dechex($arrColors[$x]), 2, 0, STR_PAD_LEFT)); 
                } 
            } 
        } 
                 return implode("", $arrColors); 
    } 
} ?>


groobo ¶
17 years ago

It's just a revision to marfastic's ligten_up script, it simply adds/subtracts mod_color to orig_color.
I use it often to adjust tonals rather than brightness only
function mod_color($orig_color, $mod, $mod_color){
    /*
        $orig_color - original html color, hex
        $mod_color - modifying color, hex
        $mod - modifier '+' or '-'
        usage: mod_color('CCCCCC', '+', '000033')
    */
    // does quick validation
    preg_match("/([0-9]|[A-F]){6}/i",$orig_color,$orig_arr);
    preg_match("/([0-9]|[A-F]){6}/i",$mod_color,$mod_arr);
    if ($orig_arr[0] && $mod_arr[0]) {
        for ($i=0; $i<6; $i=$i+2) {
            $orig_x = substr($orig_arr[0],$i,2);
            $mod_x = substr($mod_arr[0],$i,2);
            if ($mod == '+') { $new_x = hexdec($orig_x) + hexdec($mod_x); }
            else { $new_x = hexdec($orig_x) - hexdec($mod_x); }
            if ($new_x < 0) { $new_x = 0; }
            else if ($new_x > 255) { $new_x = 255; };
            $new_x = dechex($new_x);
            $ret .= $new_x;
        }
        return $ret;
    } else { return false; }
}
?>

 this1is4me at hotmail dot com ¶
14 years ago

In reply to Amit Yadav's post (hex to binary conversion):
function binfromdec($num) 
{
  $primary = "bit";
  for ($i=1; $i<=16; $i++)
    ${$primary.$i} = 0;
    if ($num & 32768)   $bit16  = 1;
  if ($num & 16384)   $bit15  = 1;
  if ($num & 8192)    $bit14  = 1;
  if ($num & 4096)    $bit13  = 1;
  if ($num & 2048)    $bit12  = 1;
  if ($num & 1024)    $bit11  = 1;
  if ($num & 512)     $bit10  = 1;
  if ($num & 256)     $bit9   = 1;
  if ($num & 128)     $bit8   = 1;
  if ($num & 64)      $bit7   = 1;
  if ($num & 32)      $bit6   = 1;
  if ($num & 16)      $bit5   = 1;
  if ($num & 8)       $bit4   = 1;
  if ($num & 4)       $bit3   = 1;
  if ($num & 2)       $bit2   = 1;
  if ($num & 1)       $bit1   = 1;
    return ($bit16. $bit15. $bit14. $bit13. $bit12. $bit11. $bit10. $bit9. $bit8. $bit7. $bit6. $bit5. $bit4. $bit3. $bit2. $bit1);
}

 maddddidley at yahoo dot com ¶
14 years ago

Function that combines two rgb colors.
function combineColors($color1, $color2) {
                $color1 = str_replace("#", '', $color1);
        $color2 = str_replace("#", '', $color2);
                $r1 = hexdec(substr($color1, 0, 2));
        $g1 = hexdec(substr($color1, 2, 2));
        $b1 = hexdec(substr($color1, 4, 2)); 
                $r2 = hexdec(substr($color2, 0, 2));
        $g2 = hexdec(substr($color2, 2, 2));
        $b2 = hexdec(substr($color2, 4, 2));
                $r3 = ceil(($r1 + $r2) / 2);
        $g3 = ceil(($g1 + $g2) / 2);
        $b3 = ceil(($b1 + $b2) / 2);
                        $color = rgbhex($r3, $g3, $b3);
        return $color = str_replace("#", '', $color);
            }


andreas.schmeiler ¶
19 years ago

Here's another hex2bin variant, works pretty well to me.
function hex2bin($hexdata) {
      for ($i=0;$i      $bindata.=chr(hexdec(substr($hexdata,$i,2)));
   }
      return $bindata;
}

 ayadav at infoprocorp dot com ¶
16 years
ago

From Amit Yadav
Hex to binary conversion
$num = hexdec("20DF");
echo binfromdec($num);
function binfromdec($num) 
{
    if ($num > 32766)    return ("Too Large!");
    if ($num & 16384)    $bit15 = 1;
    if ($num & 8192)    $bit14 = 1;
    if ($num & 4096)    $bit13 = 1;
    if ($num & 2048)    $bit12 = 1;
    if ($num & 1024)    $bit11 = 1;
    if ($num & 512)        $bit10 = 1;
    if ($num & 256)        $bit9 = 1;
    if ($num & 128)        $bit8 = 1;
    if ($num & 64)        $bit7 = 1;
    if ($num & 32)        $bit6 = 1;
    if ($num & 16)        $bit5 = 1;
    if ($num & 8)        $bit4 = 1;
    if ($num & 4)        $bit3 = 1;
    if ($num & 2)        $bit2 = 1;
    if ($num & 1)        $bit1 = 1;
    return ("" . $bit15 . $bit14 . $bit13 . $bit12 . $bit11 . $bit10 . $bit9 . $bit8 . $bit7 . $bit6 . $bit5 . $bit4 . $bit3 . $bit2 . $bit1);
}

 andy at haveland dot com ¶
11 years ago

Here's a short example to convert strings between hex and chars:

print hextostr("616E647940686176656C616E642E636F6D")."\n";

print 
strtohex("Knowledge is power")."\n";

function hextostr($x) {

  $s='';

  foreach(explode("\n",trim(chunk_split($x,2))) as $h) $s.=chr(hexdec($h));

  return($s);

}

function strtohex($x) {

  $s='';

  foreach(str_split($x) as $c) $s.=sprintf("%02X",ord($c));

  return($s);

}

?>


Rosberg - rosberglinhares at gmail dot com ¶
12 years ago

The correct version is:
function bchexdec($hex) {
    static $hexdec = array(
        "0" => 0,
        "1" => 1,
        "2" => 2,
        "3" => 3,
        "4" => 4,
        "5" => 5,
        "6" => 6,
        "7" => 7,
        "8" => 8,
        "9" => 9,
        "A" => 10,
        "B" => 11,
        "C" => 12,
        "D" => 13,
        "E" => 14,
        "F" => 15
    );
    $dec = 0;
    for ($i = strlen($hex) - 1, $e = 1; $i >= 0; $i--, $e = bcmul($e, 16)) {
        $factor = $hexdec[$hex[$i]];
        $dec = bcadd($dec, bcmul($factor, $e));
    }
    return $dec;
}