I leave code blocks them that I have made to be able to replace the content of certain blocks of JS that used eval () I hope serves to them.
// Convert hex 2 str
// Imput Example: \x68\x6f\x6c\x61\x20\x6d\x75\x6e\x64\x6f
$que=( isset( $_POST['hexadecimal'] ) )?$_POST['hexadecimal']:"";
$valores=explode( "\\\x", $que );
for ( $i=0; $i<count( $valores ) ; $i++) {
echo chr( hexdec( $valores[$i] ) ) ;
}
// Convert str 2 hex
// Imput Example: hola mundo
$que=( isset( $_POST['ascii'] ) )?$_POST['ascii']:"";
for ( $i=0; $i<strlen( $que ) ; $i++) {
echo "\\x".dechex( ord( substr( $que, $i, 1) ) ) ;
}
dechex
说明
string dechex ( int number )返回一字符串，包含有给定 number 参数的十六进制表示。所能转换的最大数值为十进制的 4294967295，其结果为 "ffffffff"。
参见 hexdec()，decbin()，decoct() 和 base_convert().。
add a note
User Contributed Notes
foros at basnek dot com
25-Jul-2006 12:13
25-Jul-2006 12:13
Mista-NiceGuy at web dot de
28-Dec-2005 09:00
28-Dec-2005 09:00
These are functions to convert roman numbers (e.g. MXC) into dec and vice versa.
Note: romdec() does not check whether a string is really roman or not. To force a user-input into a real roman number use decrom(romdec($input)). This will turn XXXX into XL for example.
<?php
function decrom($dec){
$digits=array(
1 => "I",
4 => "IV",
5 => "V",
9 => "IX",
10 => "X",
40 => "XL",
50 => "L",
90 => "XC",
100 => "C",
400 => "CD",
500 => "D",
900 => "CM",
1000 => "M"
);
krsort($digits);
$retval="";
foreach($digits as $key => $value){
while($dec>=$key){
$dec-=$key;
$retval.=$value;
}
}
return $retval;
}
function romdec($rom){
$digits=array(
"I" => 1,
"V" => 5,
"X" => 10,
"L" => 50,
"C" => 100,
"D" => 500,
"M" => 1000
);
$retval="";
$chars=array();
for($i=1;$i<=strlen($rom);$i++){
$chars[]=substr($rom,$i-1,1);
}
$step=1;
for($i=count($chars)-1;$i>=0;$i--){
if(!isset($digits[$chars[$i]])){ return "Error!"; }
if($step<=$digits[$chars[$i]]){
$step=$digits[$chars[$i]];
$retval+=$digits[$chars[$i]];
}
else{
$retval-=$digits[$chars[$i]];
}
}
return $retval;
}
echo decrom(romdec("XXXX"));
?>
cory at lavacube dot com
28-Oct-2005 07:45
28-Oct-2005 07:45
A handy little function to convert HEX colour codes to "web safe" colours...
<?php
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 $out;
}
?>
Example: color_mkwebsafe('0e5c94');
Produces: 006699
Hope this helps someone out... Happy coding. :-)
geoffrey at nevra dot net
31-Aug-2005 04:13
31-Aug-2005 04:13
As a sum up of some notes already posted here, my own strhex() function:
<?php
function strhex($string) {
$hex = '';
$len = strlen($string);
for ($i = 0; $i < $len; $i++) {
$hex .= str_pad(dechex(ord($string[$i])), 2, 0, STR_PAD_LEFT);
}
return $hex;
}
?>
pinto at serepensar dot com
02-Aug-2005 02:40
02-Aug-2005 02:40
And another built-in function
str_pad($value, 2, '0', STR_PAD_LEFT);
:)
michael at m-ganzer dot de
18-Jul-2005 09:58
18-Jul-2005 09:58
simple, non-recursive way of zerofilling (why making everything complicated, there r more than enough inbuilt functions)
function zfill($n,$a) {
return str_repeat("0",max(0,$a-strlen($n))).$n;
}
"max(0,..." as multiplier inside of "str-repeat" is preventing an error with negative values, if the string length was already higher than the accuracy parameter for zfill.
have fun! :)
trance4rm
18-Jul-2005 04:08
18-Jul-2005 04:08
a bugfix for admin AT bobfrank DOT org' s post
The original was:
<?php
function zeropad($num, $lim)
{
return (strlen($num) >= $lim) ? $num : zeropad("0" . $num);
}
?>
I couldn't get it to work, kept getting a "Missing argument 2 for zeropad()" error, even though I called the function with both arguments -- then I noticed the recursive part, and the missing $lim argument. The code that works is:
<?php
function zeropad($num, $lim)
{
return (strlen($num) >= $lim) ? $num : zeropad("0" . $num, $lim); // $lim was missing from the recursive call
// the function will prefix $num with a zero and recursively call itself
// each recursive call, $num gets one digit bigger until strlen of $num equals $lim
}
?>
oliver at realtsp dot com
14-Jun-2005 04:46
14-Jun-2005 04:46
Warning for use on 64 bit machines! The Extra length matters!
32bit machine:
php -r 'echo dechex(4294967295);'
output: ffffffff
64bit machine:
php -r 'echo dechex(4294967295);'
output: ffffffff
so far it is ok. But for slightly bigger numbers:
32bit machine:
php -r 'echo dechex(4294967296);'
output: 0
64bit machine:
php -r 'echo dechex(4294967296);'
output: 100000000
note the difference!
This is particularly important when converting negative numbers:
64bit machine:
php -r 'echo dechex(-1);'
output: ffffffffffffffff
32bit machine:
php -r 'echo dechex(-1);'
output: ffffffff
If you want your code to be portable to amd64 or xeons (which are now quite popular with hosting companies) then you must ensure that your code copes with the different length of the result for negative numbers (and the max value, although that is probably less critical).
jrisken at mn dot rr dot com
29-May-2005 10:33
29-May-2005 10:33
A less elegant but (perhaps) faster way to pad is with substr with a negative length argument. I use it in this tiny function which formats computed rgb color codes for style sheets:
<?
function toColor($n)
{
return("#".substr("000000".dechex($n),-6));
}
?>
admin AT bobfrank DOT org
02-May-2005 10:28
02-May-2005 10:28
Here is a very small zeropadding that you can use for numbers:
function zeropad($num, $lim)
{
return (strlen($num) >= $lim) ? $num : zeropad("0" . $num);
}
zeropad("234",6);
will produce:
000234
zeropad("234",1);
will produce:
234
matt dot smith at email dot ky
22-Apr-2005 12:14
22-Apr-2005 12:14
It took me hours, but I've finally figured it all out...
--
To figure up how many lines it'll take to get from,
0000 to FFFF, use this formula:
((hex_length / 2) * 255) + 1
For 0000 to FFFF, this would be: ((4 / 2) * 255) + 1 = 511
For 0000000000 to FFFFFFFFFF, this would be: ((10 / 2) * 255) + 1 = 1276
--
To figure up how many possibilities a certain hex length will give (such as that of an MD5 hash, for example), use this formula:
256^(hex_length / 2)
Like so:
hex = 0123ABCDEF
hex_length = 10
possibilities = 256^(10 / 2)
possibilities = 256^5
possibilities = 1,099,511,627,776
--
And I don't know how useful this next part is, but it's quite nifty. Just set $length to be your hex_length and it'll display all "incrementally-possible" hexadecimals, along with line numbers:
<?php
$length = 10; // Change this to the total length of your hexadecimal
function array_check($array1, $array2)
{
$count1 = count($array1);
$count2 = count($array2);
if ($count1 != $count2)
return FALSE;
$match = 0;
for ($i = 0; $i < $count1; $i++)
if ($array1[$i] == $array2[$i])
$match++;
if ($match != $count1)
return FALSE;
return TRUE;
}
function zeropad($num)
{
return (strlen($num) == 1) ? '0'.$num : $num;
}
function zeropad_lineno($num, $length)
{
while (strlen($num) < $length)
$num = '0'.$num;
return $num;
}
$hexadecimals = $length / 2;
$possibilities = /*number_format(*/ pow(256, $hexadecimals) /*)*/;
echo "A hexadecimal of this length ({$length}) has {$possibilities} possibilities.<br>\n";
echo "<br>\n";
//init
for ($i = 0; $i < $hexadecimals; $i++)
{
$x[] = '00';
$xint[] = 0;
$end[] = 'ff';
}
$line = 0;
while ( !(array_check($x, $end)) ) // while we're not currently at the end (FF..)
{
$hexstr = '';
for ($i = 0; $i < $hexadecimals; $i++)
{
$x[$i] = dechex($xint[$i]);
$hexstr .= zeropad(dechex($xint[$i]));
}
$line++;
$linestr = zeropad_lineno($line, 8);
echo "<code>{$linestr}: {$hexstr}</code><br>\n";
// hex increment
for ($i = ($hexadecimals - 1); $i >= 0; $i--)
{
// increment bit if possible
if ($xint[$i] != 255)
{
// increment bit and then break out of the for loop
$xint[$i]++;
break;
}
}
}
?>
manithu
30-Mar-2005 04:18
30-Mar-2005 04:18
If you want to fade some text from one color to another, use this function:
<?php
function colorFade($text, $color1, $color2, $HTMLelement = 'span')
{
//remove leading and trailing whitespaces.
$text = trim($text);
//split the characters of the text to an array.
$char = array();
for ($i = 0; $i < strlen($text); $i++) {
$char[$i] = substr($text, $i, 1);
}
//convert the hexadecimal colors in decimal.
$decimalColor = array();
//first color
$decimalColor[0] = hexdec(substr($color1, 0, 2));
$decimalColor[1] = hexdec(substr($color1, 2, 2));
$decimalColor[2] = hexdec(substr($color1, 4, 2));
//second color
$decimalColor[3] = hexdec(substr($color2, 0, 2));
$decimalColor[4] = hexdec(substr($color2, 2, 2));
$decimalColor[5] = hexdec(substr($color2, 4, 2));
//formated chars are stored here (the key 0 is for the first
//char and must not be removed).
$newText = array(0 => null);
//run over every character except the first and the last,
//they will be added later.
for ($i = 2; $i <= strlen($text)-1; $i++) {
//check if the character is only a whitespace. If yes,
//save the whitespace without adding color and proceed
//to the next character.
if (!trim($char[$i-1])) {
$newText[] = $char[$i-1];
continue;
}
//calculate the (hex) color for this character.
$color = array();
//red
$color[] = dechex(($decimalColor[0] - $decimalColor[3])
/ strlen($text) * $i + $decimalColor[3]);
//green
$color[] = dechex(($decimalColor[1] - $decimalColor[4])
/ strlen($text) * $i + $decimalColor[4]);
//blue
$color[] = dechex(($decimalColor[2] - $decimalColor[5])
/ strlen($text) * $i + $decimalColor[5]);
//check if every color part is 2 chars long, if not, repeat it.
foreach ($color as $k => $v) {
if (strlen($v) < 2) {
$color[$k] = str_repeat($v, 2);
}
}
//merge the parts to the full hex color.
$color = implode($color, '');
//Save the formated char.
$newText[] = '<'.$HTMLelement.' style="color:#'.$color.'">'.
$char[$i-1].'</'.$HTMLelement.'>';
}
//add first char.
$newText[0] = '<'.$HTMLelement.' style="color:#'.$color2.'">'.
$char[0].'</'.$HTMLelement.'>';
//add last char.
$newText[] = '<'.$HTMLelement.' style="color:#'.$color1.'">'.
$char[strlen($text)-1].'</'.$HTMLelement.'>';
//merge the characters and return it.
return implode($newText, '');
}
?>
$color1 is the start color, $color2 the end color.
I hope this helps somebody.
morten at nilsen dot com
02-Jan-2005 08:30
02-Jan-2005 08:30
I see a lot of less-than-optimal functions posted on this page, so I feel I have to give some better examples...
due to the sheer size of this collection, I have made it available on my server, rather than copy/paste it into these comments.
http://ryo-ohki.4th-age.com/demos/able.php
and
http://ryo-ohki.4th-age.com/demos/able.phps
dechex replacement function from above source:
<?php
define('BIT_BYTE', 8); // bits per byte
define('HEX_BYTE', BIT_BYTE/4); // hex digits in a byte
define('BIT_INT', 32); // sizeof(int)
define('HEX_INT', BIT_INT / (BIT_BYTE/HEX_BYTE)); // hex digits in an int
function i2h($int, $group=HEX_BYTE, $size=HEX_INT, $sep=' ') {
$ret = '';
while($size--) {
$n=($int>>($size*4)) & 0xf;
$ret .= $n>9?chr(55 + $n):$n;
if($size && $size%$group == 0) $ret .= $sep;
}
return $ret;
}
echo i2h(rand(1,2)==1?-mt_rand():mt_rand());
?>
wangster at darkcore dot net
15-Dec-2004 03:36
15-Dec-2004 03:36
This function will take a string and convert it into a hexdump.
e.g.
3c666f6e 74207369 7a653d22 33223e4c <font.size."3">L
6561726e 20686f77 20746f20 62652061 earn.how.to.be.a
function hexdump($string) {
$hex="";
$substr = "";
for ($i=0; $i < strlen($string) ;$i++) {
if(!($i % 4) && $i != 0) {
$hex .= " ";
}
if(!($i % 16) && $i != 0) {
$clean = preg_replace("/[^a-zA-Z0-9!-.<>\/]/",".",$substr);
$hex .= " ".htmlentities($clean)."\n";
$substr = "";
}
$substr .= $string[$i];
$hex .= dechex(ord($string[$i]));
}
return $hex;
}
12-Dec-2004 11:31
If you need to generate random HEX-color, use this:
<?php
function random_hex_color(){
return sprintf("%02X%02X%02X", mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
}
$hex = random_hex_color(); // 09B826
?>
Enjoy.
12-Dec-2004 05:30
If you need to convert RGB-color into HEX-color, use this:
<?php
function rgb2hex($rgb){
return sprintf("%06X", $rgb);
}
$hex = rgb2hex(65280); // 00FF00
?>
Ruben Barkow ( at web dot de)
24-May-2004 02:46
24-May-2004 02:46
this function generates an hex-colorcode out of a string.
usefull if you want to show a list of words all in different colors, that should remain its color even if the order changes.
(if the string is empty, it gives back a random color)
function word2color($w){
if (strlen($w)==0) return substr('00000' . dechex(mt_rand(0, 0xffffff)), -6);
while (strlen($w)<6) $w.=$w;
$minbrightness=1; // range from 0 to 15, if this is 0 then for ex. black is allowed
$max_brightness=14; // range from 0 to 15, if this is 15 then for ex. white is allowed
$plus_red=0; // set one of these to set the probability of one of these colors higher
$plus_green=0;
$plus_blue=0;
for ($i=0; $i<6; $i++) {
#$r.= '">';// this is a depug mode, to see the color written
$plus=0;
if ($plus_red<>0 and $i==0) $plus=$plus_red;
if ($plus_green<>0 and $i==2) $plus=$plus_green;
if ($plus_blue<>0 and $i==4) $plus=$plus_blue;
$c=$w[round(strlen($w)/6*$i)];
$dec=ord($c)%($max_brightness+$plus-$minbrightness) +$minbrightness+$plus;
if ($dec>$max_brightness-$minbrightness) $dec=$max_brightness-$minbrightness;
$r.= strtoupper( dechex($dec) );
}
return $r;
}
admin[TAKETHISOUT] at torsoft dot no-ip dot com
22-Apr-2004 03:01
22-Apr-2004 03:01
<?php
/*
here are two functions, some might find them useful (maybe for encoding)
converting string to hex and hex to string:
*/
function strhex($string)
{
$hex="";
for ($i=0;$i<strlen($string);$i++)
$hex.=(strlen(dechex(ord($string[$i])))<2)? "0".dechex(ord($string[$i])): dechex(ord($string[$i]));
return $hex;
}
function hexstr($hex)
{
$string="";
for ($i=0;$i<strlen($hex)-1;$i+=2)
$string.=chr(hexdec($hex[$i].$hex[$i+1]));
return $string;
}
?>
daevid at daevid dot com
19-Mar-2004 06:59
19-Mar-2004 06:59
Here's my version of a red->yellow->green gradient:
<?php
function colorMeter($percent, $invert = false)
{
//$percent is in the range 0.0 <= percent <= 1.0
// integers are assumed to be 0% - 100%
// and are converted to a float 0.0 - 1.0
// 0.0 = red, 0.5 = yellow, 1.0 = green
//$invert will make the color scale reversed
// 0.0 = green, 0.5 = yellow, 1.0 = red
//convert (int)% values to (float)
if (is_int($percent)) $percent = $percent * 0.01;
$R = min((2.0 * (1.0-$percent)), 1.0) * 255.0;
$G = min((2.0 * $percent), 1.0) * 255.0;
$B = 0.0;
return (($invert) ?
sprintf("%02X%02X%02X",$G,$R,$B)
: sprintf("%02X%02X%02X",$R,$G,$B));
} //colorMeter
?>
and use it like this:
<TABLE BORDER=1 WIDTH="300">
<?php
for ($i = 0.0; $i <= 1.0; $i += 0.10)
{
$RGB = colorMeter($i);
print "<TR><TD BGCOLOR='".$RGB."'>".$i."</TD><TD>
<PRE>".$RGB."</PRE></TD></TR>\n";
}
?>
</TABLE>
<P>
<TABLE BORDER=1 WIDTH="300">
<?php
for ($i = 0; $i <= 100; $i += 10)
{
$RGB = colorMeter(intval($i), true);
print "<TR><TD BGCOLOR='".$RGB."'>".$i."</TD><TD>
<PRE>".$RGB."</PRE></TD></TR>\n";
}
?>
</TABLE>
thr at recide dot net
10-Feb-2004 08:39
10-Feb-2004 08:39
/*
* RGB-Colorcodes(i.e: 255 0 255) to HEX-Colorcodes (i.e: FF00FF)
*/
function rgb2hex($rgb){
if(!is_array($rgb) || count($rgb) != 3){
echo "Argument must be an array with 3 integer elements";
return false;
}
for($i=0;$i<count($rgb);$i++){
if(strlen($hex[$i] = dechex($rgb[$i])) == 1){
$hex[$i] = "0".$hex[$i];
}
}
return $hex;
}
/* Example */
print_r(rgb2hex(array(10,255,255)));
mina86 at tlen dot pl
06-Feb-2004 01:05
06-Feb-2004 01:05
Easiest :P way to create random hex color:
<?php
function rand_color() {
return substr('00000' . dechex(mt_rand(0, 0xffffff)), -6);
}
?>
paeppi at actionorg dot de
30-Dec-2003 02:53
30-Dec-2003 02:53
Easier way to create random hex color:
<?php
function rand_color() {
$hexcolor = dechex(mt_rand(0,16777215));
while (strlen($hexcolor) < 6) {
$hexcolor = $hexcolor."0";
}
return $hexcolor;
}
echo "#".rand_color();
?>
huda m elmatsani <justhuda at netscape dot net>
17-Sep-2003 06:36
17-Sep-2003 06:36
Create Random Hex Color:
function make_seed() {
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((double) $usec * 100000);
}
function rand_hex() {
mt_srand(make_seed());
$randval = mt_rand(0,255);
//convert to hex
return sprintf("%02X",$randval);
}
function random_color(){
return "#".rand_hex().rand_hex().rand_hex();
}
hme ;)
paeppi at actionorg dot de
04-Aug-2003 10:42
04-Aug-2003 10:42
# One example how to convert a decimal number into any other system (here 32 digits -- 0 to v) and how to convert back.
# Just replace the "32" in my functions with the number of digits in "your" system, and continue the replace-lists.
# This is surely not the very best way to do this, but it hopefully helps :-)
function decttw($int_dec) {
$s = $int_dec;
while ($i < 19) {
$exp = pow(32,18 - $i);
$modulo = fmod($s,$exp);
$value = ($s - $modulo) / $exp;
if (($value > 0) && ($start != 1)) {
$start = 1;
}
if ($start == 1) {
$decs = $value;
$decs = ereg_replace ("10", "a", $decs);
$decs = ereg_replace ("11", "b", $decs);
$decs = ereg_replace ("12", "c", $decs);
$decs = ereg_replace ("13", "d", $decs);
$decs = ereg_replace ("14", "e", $decs);
$decs = ereg_replace ("15", "f", $decs);
$decs = ereg_replace ("16", "g", $decs);
$decs = ereg_replace ("17", "h", $decs);
$decs = ereg_replace ("18", "i", $decs);
$decs = ereg_replace ("19", "j", $decs);
$decs = ereg_replace ("20", "k", $decs);
$decs = ereg_replace ("21", "l", $decs);
$decs = ereg_replace ("22", "m", $decs);
$decs = ereg_replace ("23", "n", $decs);
$decs = ereg_replace ("24", "o", $decs);
$decs = ereg_replace ("25", "p", $decs);
$decs = ereg_replace ("26", "q", $decs);
$decs = ereg_replace ("27", "r", $decs);
$decs = ereg_replace ("28", "s", $decs);
$decs = ereg_replace ("29", "t", $decs);
$decs = ereg_replace ("30", "u", $decs);
$decs = ereg_replace ("31", "v", $decs);
$int_value = $int_value.$decs;
}
$s = $s - $value * $exp;
$i++;
}
return $int_value;
}
function ttwdec($int_ttw) {
$digits = strlen($int_ttw);
while ($i < $digits) {
$s = substr($int_ttw,$i,1);
$decs = $s;
$decs = ereg_replace ("a", "10", $decs);
$decs = ereg_replace ("b", "11", $decs);
$decs = ereg_replace ("c", "12", $decs);
$decs = ereg_replace ("d", "13", $decs);
$decs = ereg_replace ("e", "14", $decs);
$decs = ereg_replace ("f", "15", $decs);
$decs = ereg_replace ("g", "16", $decs);
$decs = ereg_replace ("h", "17", $decs);
$decs = ereg_replace ("i", "18", $decs);
$decs = ereg_replace ("j", "19", $decs);
$decs = ereg_replace ("k", "20", $decs);
$decs = ereg_replace ("l", "21", $decs);
$decs = ereg_replace ("m", "22", $decs);
$decs = ereg_replace ("n", "23", $decs);
$decs = ereg_replace ("o", "24", $decs);
$decs = ereg_replace ("p", "25", $decs);
$decs = ereg_replace ("q", "26", $decs);
$decs = ereg_replace ("r", "27", $decs);
$decs = ereg_replace ("s", "28", $decs);
$decs = ereg_replace ("t", "29", $decs);
$decs = ereg_replace ("u", "30", $decs);
$decs = ereg_replace ("v", "31", $decs);
$i++;
$value = $decs * pow(32,($digits - $i));
$int_value = $int_value + $value;
}
return $int_value;
}
m0sh3 at hotmail dot com
30-Jul-2003 08:41
30-Jul-2003 08:41
This will can convert decimal of more than 2^48 in any PHP version:
$hex = dechex($dec>>24).dechex($dec & 0xFFFFFF)
allan-wegan at allan-wegan dot de
20-Jul-2003 01:53
20-Jul-2003 01:53
now, here is a nice and small function to convert integers to hex strings and it avoids use of the DECHEX funtion because that function changed it's behavior too often in the past (now, in PHP version 4.3.2 it works with numbers bigger than 0x7FFFFFFF correctly, but i need to be backward compatible).
function &formatIntegerForOutput($value) {
$text = "00000000";
$transString = "0123456789ABCDEF";
// handle highest nibble (nibble 7):
$nibble = $value & 0x70000000;
$nibble >>= 28;
if ($value < 0) {
$nibble = $nibble | 0x00000008;
}
$text[0] = $transString[$nibble];
$value &= 0x0FFFFFFF;
// nibbles 0 to 6:
for ($a = 7; $a > 0; $a --) {
$nibble = $value & 0x0000000F;
$text[$a] = $transString[$nibble];
$value >>= 4;
}
return $text
}
this function should be not too slow and is really simple.
I don't know, if the DECHEX function in the future will pad it's output to ever be 8 characters in length - so for backward compatibility reasons even in future PHP versions i avoided to use it.
paoligno at tin dot it
15-Mar-2003 11:32
15-Mar-2003 11:32
you can use this workaround (raw but simple and efficient)
$string=DecHex($string*1)
bye bye
the_tenth at pandora dot be
30-Sep-2002 05:12
30-Sep-2002 05:12
<?
function dec2hex($number) {
$length=16;
$hexval="";
while ($number>0) {
$remainder=bcmod($number,16);
if ($remainder<10)
$hexval=$remainder.$hexval;
elseif ($remainder==10)
$hexval="A".$hexval;
elseif ($remainder==11)
$hexval="B".$hexval;
elseif ($remainder==12)
$hexval="C".$hexval;
elseif ($remainder==13)
$hexval="D".$hexval;
elseif ($remainder==14)
$hexval="E".$hexval;
elseif ($remainder==15)
$hexval="F".$hexval;
$number=bcdiv($number,16);
}
while (strlen($hexval)<$length) $hexval="0".$hexval;
return $hexval;
}
$tmp = "<table width='643' border='1'>";
$x = 1;
$y = 1;
$z = dec2hex($x);
$q = dec2hex($y);
for ($i=1;$i<65;$i++){
$x= bcpow(2,($i-1));
$z = dec2hex($x);
$tmp .="<tr><td width='20' align='center' bgcolor='#808080'><font color='#ffffff'>". $i;
$tmp .="</font></td><td width='5'>2<sup>". ($i-1) . "</sup></td><td width='2'>=</td></td><td>" . $x . "</td>";
$tmp .="<td>".$z."</td><td>".$y."</td><td>".$q."</td></tr>";
$y = bcsub(bcpow(2,$i+1),1);
$q = dec2hex($y);
}
$tmp .= "</table>";
echo $tmp;
?>
monkyNOSPAM at phpfi dot org dot invalid
24-Sep-2002 10:20
24-Sep-2002 10:20
Here's how to use bitwise operations for RGB2hex conversion. This function returns hexadesimal rgb value just like one submitted by gurke@bigfoot.com above.
function hexColor($color) {
return dechex(($color[0]<<16)|($color[1]<<8)|$color[2]);
}
example:
$col[0] = 25;
$col[1] = 255;
$col[2] = 55;
print hexColor($col);
joost at bingopaleis dot com
29-Apr-2002 12:21
29-Apr-2002 12:21
Here are two functions that will convert large dec numbers to hex and vice versa. And I really mean LARGE, much larger than any function posted earlier.
<pre>
// Input: A decimal number as a String.
// Output: The equivalent hexadecimal number as a String.
function dec2hex($number)
{
$hexvalues = array('0','1','2','3','4','5','6','7',
'8','9','A','B','C','D','E','F');
$hexval = '';
while($number != '0')
{
$hexval = $hexvalues[bcmod($number,'16')].$hexval;
$number = bcdiv($number,'16',0);
}
return $hexval;
}
// Input: A hexadecimal number as a String.
// Output: The equivalent decimal number as a String.
function hex2dec($number)
{
$decvalues = 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');
$decval = '0';
$number = strrev($number);
for($i = 0; $i < strlen($number); $i++)
{
$decval = bcadd(bcmul(bcpow('16',$i,0),$decvalues[$number{$i}]), $decval);
}
return $decval;
}
</pre>
jfren484 at hotmail dot com
13-Feb-2002 07:47
13-Feb-2002 07:47
Here's a function which works for decimal values up to 9007199254740992 (hex 20000000000000).
function dec2hex($dec)
{
$hex = ($dec == 0 ? '0' : '');
while ($dec > 0)
{
$hex = dechex($dec - floor($dec / 16) * 16) . $hex;
$dec = floor($dec / 16);
}
return $hex;
}
kristoffer at caveo dot se
11-Feb-2002 09:39
11-Feb-2002 09:39
Heres a example of dec to html hex gradient. Have fun :)
//Amount of gradients
$l = 20;
//Start color
$start[0] = "255"; //red
$start[1] = "0"; //green
$start[2] = "255"; //blue
//End color
$end[0] = "255"; //red
$end[1] = "255"; //green
$end[2] = "255"; //blue
for ($t = 1; $t < $l;) {
$x = $x * $t;
for ($i = 0; $i < 3;) {
$buffer[$i] = $start[$i] - $end[$i];
$buffer[$i] = floor($buffer[$i] / $l);
$rgb[$i] = $start[$i] - ($buffer[$i] * $t);
if ($rgb[$i] > 255) {
$rgb[$i] = 255;
}
$rgb[$i] = dechex($rgb[$i]);
$rgb[$i] = strtoupper($rgb[$i]);
if (strlen($rgb[$i]) < 2) {
$rgb[$i] = "0$rgb[$i]";
}
$i++;
}
$color = "$rgb[0]$rgb[1]$rgb[2]";
echo "$color";
$t++;
}
?>
c_westerbeek at hotmail dot com
28-Sep-2001 07:48
28-Sep-2001 07:48
echo dec2hex(123, 5);
will show: 0007b
echo dec2hex(708191, 10);
will show: 00000ace5f
c_westerbeek at hotmail dot com
25-Sep-2001 06:20
25-Sep-2001 06:20
a dec 2 hex function that goes way beyon 7fffffff. I don't now wat the limit is. float's precision is 14 decimal digits so the precision of dec2hex should be 5AF3107A3FFF (=99999999999999)
function dec2hex($number, $length) {
$hexval="";
while ($number>0) {
$remainder=$number%16;
if ($remainder<10)
$hexval=$remainder.$hexval;
elseif ($remainder==10)
$hexval="a".$hexval;
elseif ($remainder==11)
$hexval="b".$hexval;
elseif ($remainder==12)
$hexval="c".$hexval;
elseif ($remainder==13)
$hexval="d".$hexval;
elseif ($remainder==14)
$hexval="e".$hexval;
elseif ($remainder==15)
$hexval="f".$hexval;
$number=floor($number/16);
}
while (strlen($hexval)<$length) $hexval="0".$hexval;
//this is just to add zero's at the beginning to make hexval a certain length
return $hexval;
}
gurke at bigfoot dot com
26-Mar-2001 09:31
26-Mar-2001 09:31
usefull if you need to convert decimal colors to html style hex colors:
function hexColor($color) {
return sprintf("%02X%02X%02X",$color[0],$color[1],$color[2]);
}
example:
$col[0] = 25;
$col[1] = 255;
$col[2] = 55;
print hexColor($col);
22-Mar-2001 02:26
# dec2hex function
#
# For hex numbers that go up to FFFFFFFF (instead of 7FFFFFFF)
#
# crude but does the job...
#
function dec2hex($dec)
{
if($dec > 2147483648)
{
$result = dechex($dec - 2147483648);
$prefix = dechex($dec / 268435456);
$suffix = substr($result,-7);
$hex = $prefix.str_pad($suffix, 7, "0000000", STR_PAD_LEFT);
}
else
{
$hex = dechex($dec);
}
return($hex);
}