lib/Vizhash16x16.php
<?php
/**
* VizHash_GD
*
* Visual Hash implementation in php4+GD,
* stripped down and modified version for PrivateBin
*
* @link https://sebsauvage.net/wiki/doku.php?id=php:vizhash_gd
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 0.0.5 beta PrivateBin 1.7.1
*/
namespace PrivateBin;
/**
* Vizhash16x16
*
* Example:
* $vz = new Vizhash16x16();
* $data = $vz->generate(sha512('hello'));
* header('Content-type: image/png');
* echo $data;
* exit;
*/
class Vizhash16x16
{
/**
* hash values
*
* @access private
* @var array
*/
private $VALUES;
/**
* index of current value
*
* @access private
* @var int
*/
private $VALUES_INDEX;
/**
* image width
*
* @access private
* @var int
*/
private $width;
/**
* image height
*
* @access private
* @var int
*/
private $height;
/**
* constructor
*
* @access public
*/
public function __construct()
{
$this->width = 16;
$this->height = 16;
}
/**
* Generate a 16x16 png corresponding to $text.
*
* The given text should to be 128 to 150 characters long
*
* @access public
* @param string $text
* @return string PNG data. Or empty string if GD is not available.
*/
public function generate($text)
{
if (!function_exists('gd_info')) {
return '';
}
$textlen = strlen($text);
// We convert the hash into an array of integers.
$this->VALUES = array();
for ($i = 0; $i < $textlen; $i = $i + 2) {
array_push($this->VALUES, hexdec(substr($text, $i, 2)));
}
$this->VALUES_INDEX = 0; // to walk the array.
// Then use these integers to drive the creation of an image.
$image = imagecreatetruecolor($this->width, $this->height);
$r = $r0 = $this->getInt();
$g = $g0 = $this->getInt();
$b = $b0 = $this->getInt();
// First, create an image with a specific gradient background.
$op = 'v';
if (($this->getInt() % 2) == 0) {
$op = 'h';
}
$image = $this->degrade($image, $op, array($r0, $g0, $b0), array(0, 0, 0));
for ($i = 0; $i < 7; ++$i) {
$action = $this->getInt();
$color = imagecolorallocate($image, $r, $g, $b);
$r = $r0 = ($r0 + $this->getInt() / 25) % 256;
$g = $g0 = ($g0 + $this->getInt() / 25) % 256;
$b = $b0 = ($b0 + $this->getInt() / 25) % 256;
$this->drawshape($image, $action, $color);
}
$color = imagecolorallocate($image, $this->getInt(), $this->getInt(), $this->getInt());
$this->drawshape($image, $this->getInt(), $color);
ob_start();
imagepng($image);
$imagedata = ob_get_contents();
ob_end_clean();
imagedestroy($image);
return $imagedata;
}
/**
* Returns a single integer from the $VALUES array (0...255)
*
* @access private
* @return int
*/
private function getInt()
{
$v = $this->VALUES[$this->VALUES_INDEX];
++$this->VALUES_INDEX;
$this->VALUES_INDEX %= count($this->VALUES); // Warp around the array
return $v;
}
/**
* Returns a single integer from the array (roughly mapped to image width)
*
* @access private
* @return int
*/
private function getX()
{
return $this->width * $this->getInt() / 256;
}
/**
* Returns a single integer from the array (roughly mapped to image height)
*
* @access private
* @return int
*/
private function getY()
{
return $this->height * $this->getInt() / 256;
}
/**
* Gradient function
*
* taken from:
* @link https://www.supportduweb.com/scripts_tutoriaux-code-source-41-gd-faire-un-degrade-en-php-gd-fonction-degrade-imagerie.html
*
* @access private
* @param resource $img
* @param string $direction
* @param array $color1
* @param array $color2
* @return resource
*/
private function degrade($img, $direction, $color1, $color2)
{
if ($direction == 'h') {
$size = imagesx($img);
$sizeinv = imagesy($img);
} else {
$size = imagesy($img);
$sizeinv = imagesx($img);
}
$diffs = array(
($color2[0] - $color1[0]) / $size,
($color2[1] - $color1[1]) / $size,
($color2[2] - $color1[2]) / $size,
);
for ($i = 0; $i < $size; ++$i) {
$r = $color1[0] + ($diffs[0] * $i);
$g = $color1[1] + ($diffs[1] * $i);
$b = $color1[2] + ($diffs[2] * $i);
if ($direction == 'h') {
imageline($img, $i, 0, $i, $sizeinv, imagecolorallocate($img, $r, $g, $b));
} else {
imageline($img, 0, $i, $sizeinv, $i, imagecolorallocate($img, $r, $g, $b));
}
}
return $img;
}
/**
* Draw a shape
*
* @access private
* @param resource $image
* @param int $action
* @param int $color
*/
private function drawshape($image, $action, $color)
{
switch ($action % 7) {
case 0:
imagefilledrectangle($image, $this->getX(), $this->getY(), $this->getX(), $this->getY(), $color);
break;
case 1:
case 2:
imagefilledellipse($image, $this->getX(), $this->getY(), $this->getX(), $this->getY(), $color);
break;
case 3:
$points = array($this->getX(), $this->getY(), $this->getX(), $this->getY(), $this->getX(), $this->getY(), $this->getX(), $this->getY());
imagefilledpolygon($image, $points, 4, $color);
break;
default:
$start = $this->getInt() * 360 / 256;
$end = $start + $this->getInt() * 180 / 256;
imagefilledarc($image, $this->getX(), $this->getY(), $this->getX(), $this->getY(), $start, $end, $color, IMG_ARC_PIE);
}
}
}