hexdec

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

    hexdec — Hexadecimal to decimal

    Description

    hexdec(string $hex_string): int|float

    Returns the decimal equivalent of the hexadecimal number represented by the hex_string argument. hexdec() converts a hexadecimal string to a decimal number.

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

    Parameters

    hex_string

    The hexadecimal string to convert

    Return Values

    The decimal representation of hex_string

    Changelog

    Version Description
    7.4.0 Passing invalid characters will now generate a deprecation notice. The result will still be computed as if the invalid characters did not exist.

    Examples

    Example #1 hexdec() example

    <?php
    var_dump    (hexdec("ee")); // prints "int(238)"
    var_dump(hexdec("a0")); // prints "int(160)"
    ?>

    Example #2 hexdec() with Invalid Characters

    <?php
    var_dump    (hexdec("See")); // print "int(238)"
    var_dump(hexdec("that")); // print "int(10)"
    ?>

    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

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    User Contributed Notes 2 notes

    up
    32
    hafees at msn dot com
    15 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

    <?php
    /**
    * 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
    up
    2
    repley at freemail dot it
    19 years ago
    From color to color to ...... to color with fade effect. Good for dynamic bar chart.

    <?php
    //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 = '<table border=1 width="300">' . "\n";

    for (    $i = 0; $i < $tot; $i++){
    $table .= ' <tr><td bgcolor="' . $a[$i] . '">' . ($i+1) .'</td><td><pre>' . $a[$i] . '</pre></td></tr>' . "\n";
    }

    $table .= '</table><br /><br />';

    echo     '<br />Demanded steps = ' . $steps . '<br />';
    echo     'Returned steps = ' . $tot;

    if(    $steps == $tot){
    echo     '<br />OK.' . $steps . ' = ' . $tot . '<br />';
    }else{
    echo     '<br /><span style="color:#FF0000">FAILED! Demanded steps and returned steps are NOT equal!: ' . $steps . ' != ' . $tot . '</span><br />';
    }

    echo     $table;

    }
    //end test
    ?>

    Repley.
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