rand_avatar.php

<?php
/**
 * 随机头像生成
 * 生成算法来自Github，具体出处找不到了，做了少量修改
 * @author loveyu
 */

/**
 * 头像HASH值
 */
define("AVATAR_HASH", (isset($_GET['hash']) && !empty($_GET['hash'])) ? md5($_GET['hash']) : md5(rand(0, 1000000)));

/**
 * 头像大小
 */
define("AVATAR_SIZE", (isset($_GET['size']) && $_GET['size'] > 10) ? $_GET['size'] : 100);

/**
 * generate sprite for corners and sides
 * @param $shape
 * @param $R
 * @param $G
 * @param $B
 * @param $rotation
 * @return resource
 */
function getsprite($shape, $R, $G, $B, $rotation){
	global $spriteZ;
	$sprite = imagecreatetruecolor($spriteZ, $spriteZ);
	imageantialias($sprite, true);
	$fg = imagecolorallocate($sprite, $R, $G, $B);
	$bg = imagecolorallocate($sprite, 255, 255, 255);
	imagefilledrectangle($sprite, 0, 0, $spriteZ, $spriteZ, $bg);
	switch($shape){
		case 0: // triangle
			$shape = array(0.5, 1, 1, 0, 1, 1);
			break;
		case 1: // parallelogram
			$shape = array(0.5, 0, 1, 0, 0.5, 1, 0, 1);
			break;
		case 2: // mouse ears
			$shape = array(0.5, 0, 1, 0, 1, 1, 0.5, 1, 1, 0.5);
			break;
		case 3: // ribbon
			$shape = array(0, 0.5, 0.5, 0, 1, 0.5, 0.5, 1, 0.5, 0.5);
			break;
		case 4: // sails
			$shape = array(0, 0.5, 1, 0, 1, 1, 0, 1, 1, 0.5);
			break;
		case 5: // fins
			$shape = array(1, 0, 1, 1, 0.5, 1, 1, 0.5, 0.5, 0.5);
			break;
		case 6: // beak
			$shape = array(0, 0, 1, 0, 1, 0.5, 0, 0, 0.5, 1, 0, 1);
			break;
		case 7: // chevron
			$shape = array(0, 0, 0.5, 0, 1, 0.5, 0.5, 1, 0, 1, 0.5, 0.5);
			break;
		case 8: // fish
			$shape = array(0.5, 0, 0.5, 0.5, 1, 0.5, 1, 1, 0.5, 1, 0.5, 0.5, 0, 0.5);
			break;
		case 9: // kite
			$shape = array(0, 0, 1, 0, 0.5, 0.5, 1, 0.5, 0.5, 1, 0.5, 0.5, 0, 1);
			break;
		case 10: // trough
			$shape = array(0, 0.5, 0.5, 1, 1, 0.5, 0.5, 0, 1, 0, 1, 1, 0, 1);
			break;
		case 11: // rays
			$shape = array(0.5, 0, 1, 0, 1, 1, 0.5, 1, 1, 0.75, 0.5, 0.5, 1, 0.25);
			break;
		case 12: // double rhombus
			$shape = array(0, 0.5, 0.5, 0, 0.5, 0.5, 1, 0, 1, 0.5, 0.5, 1, 0.5, 0.5, 0, 1);
			break;
		case 13: // crown
			$shape = array(0, 0, 1, 0, 1, 1, 0, 1, 1, 0.5, 0.5, 0.25, 0.5, 0.75, 0, 0.5, 0.5, 0.25);
			break;
		case 14: // radioactive
			$shape = array(0, 0.5, 0.5, 0.5, 0.5, 0, 1, 0, 0.5, 0.5, 1, 0.5, 0.5, 1, 0.5, 0.5, 0, 1);
			break;
		default: // tiles
			$shape = array(0, 0, 1, 0, 0.5, 0.5, 0.5, 0, 0, 0.5, 1, 0.5, 0.5, 1, 0.5, 0.5, 0, 1);
			break;
	}
	/* apply ratios */
	for($i = 0; $i < count($shape); $i++){
		$shape[$i] = $shape[$i] * $spriteZ;
	}
	imagefilledpolygon($sprite, $shape, count($shape) / 2, $fg);
	/* rotate the sprite */
	for($i = 0; $i < $rotation; $i++){
		$sprite = imagerotate($sprite, 90, $bg);
	}
	return $sprite;
}

/**
 * generate sprite for center block
 * @param $shape
 * @param $fR
 * @param $fG
 * @param $fB
 * @param $bR
 * @param $bG
 * @param $bB
 * @param $usebg
 * @return resource
 */
function getcenter($shape, $fR, $fG, $fB, $bR, $bG, $bB, $usebg){
	global $spriteZ;
	$sprite = imagecreatetruecolor($spriteZ, $spriteZ);
	imageantialias($sprite, true);
	$fg = imagecolorallocate($sprite, $fR, $fG, $fB);
	/* make sure there's enough contrast before we use background color of side sprite */
	if($usebg > 0 && (abs($fR - $bR) > 127 || abs($fG - $bG) > 127 || abs($fB - $bB) > 127)){
		$bg = imagecolorallocate($sprite, $bR, $bG, $bB);
	} else{
		$bg = imagecolorallocate($sprite, 255, 255, 255);
	}
	imagefilledrectangle($sprite, 0, 0, $spriteZ, $spriteZ, $bg);
	switch($shape){
		case 0: // empty
			$shape = array();
			break;
		case 1: // fill
			$shape = array(0, 0, 1, 0, 1, 1, 0, 1);
			break;
		case 2: // diamond
			$shape = array(0.5, 0, 1, 0.5, 0.5, 1, 0, 0.5);
			break;
		case 3: // reverse diamond
			$shape = array(0, 0, 1, 0, 1, 1, 0, 1, 0, 0.5, 0.5, 1, 1, 0.5, 0.5, 0, 0, 0.5);
			break;
		case 4: // cross
			$shape = array(0.25, 0, 0.75, 0, 0.5, 0.5, 1, 0.25, 1, 0.75, 0.5, 0.5, 0.75, 1, 0.25, 1, 0.5, 0.5, 0, 0.75, 0, 0.25, 0.5, 0.5);
			break;
		case 5: // morning star
			$shape = array(0, 0, 0.5, 0.25, 1, 0, 0.75, 0.5, 1, 1, 0.5, 0.75, 0, 1, 0.25, 0.5);
			break;
		case 6: // small square
			$shape = array(0.33, 0.33, 0.67, 0.33, 0.67, 0.67, 0.33, 0.67);
			break;
		case 7: // checkerboard
			$shape = array(0, 0, 0.33, 0, 0.33, 0.33, 0.66, 0.33, 0.67, 0, 1, 0, 1, 0.33, 0.67, 0.33, 0.67, 0.67, 1, 0.67, 1, 1, 0.67, 1, 0.67, 0.67,
						   0.33, 0.67, 0.33, 1, 0, 1, 0, 0.67, 0.33, 0.67, 0.33, 0.33, 0, 0.33);
			break;
	}
	/* apply ratios */
	for($i = 0; $i < count($shape); $i++){
		$shape[$i] = $shape[$i] * $spriteZ;
	}
	if(count($shape) > 0){
		imagefilledpolygon($sprite, $shape, count($shape) / 2, $fg);
	}
	return $sprite;
}

/**
 * 调整颜色
 * @param $r
 * @param $g
 * @param $b
 */
function fix_rgb(&$r, &$g, &$b){
	if($r==0){
		$r = 10;
	}
	if($g==0){
		$g = 10;
	}
	if($b ==0){
		$b = 10;
	}
	while($r < 210){
		$r *= 1.3;
	}
	while($g < 100){
		$g *= 1.3;
	}
	while($b < 180){
		$b *= 1.3;
	}
	if($r > 255){
		$r = 511 - $r;
	}
	if($g > 255){
		$g = 511 - $g;
	}
	if($b > 255){
		$b = 511 - $b;
	}
}


$csh = hexdec(substr(AVATAR_HASH, 0, 1)); // corner sprite shape
$ssh = hexdec(substr(AVATAR_HASH, 1, 1)); // side sprite shape
$xsh = hexdec(substr(AVATAR_HASH, 2, 1)) & 7; // center sprite shape

$cro = hexdec(substr(AVATAR_HASH, 3, 1)) & 3; // corner sprite rotation
$sro = hexdec(substr(AVATAR_HASH, 4, 1)) & 3; // side sprite rotation
$xbg = hexdec(substr(AVATAR_HASH, 5, 1)) % 2; // center sprite background

/* corner sprite foreground color */
$cfr = hexdec(substr(AVATAR_HASH, 6, 2));
$cfg = hexdec(substr(AVATAR_HASH, 8, 2));
$cfb = hexdec(substr(AVATAR_HASH, 10, 2));
fix_rgb($cfr, $cfg, $cfb);

/* side sprite foreground color */
$sfr = hexdec(substr(AVATAR_HASH, 12, 2));
$sfg = hexdec(substr(AVATAR_HASH, 14, 2));
$sfb = hexdec(substr(AVATAR_HASH, 16, 2));
fix_rgb($sfr, $sfg, $sfb);

/* final angle of rotation */
$angle = hexdec(substr(AVATAR_HASH, 18, 2));


/* size of each sprite */
$spriteZ = 128;

/* start with blank 3x3 identicon */
$identicon = imagecreatetruecolor($spriteZ * 3, $spriteZ * 3);
imageantialias($identicon, true);

/* assign white as background */
$bg = imagecolorallocate($identicon, 255, 255, 255);
imagefilledrectangle($identicon, 0, 0, $spriteZ, $spriteZ, $bg);

/* generate corner sprites */
$corner = getsprite($csh, $cfr, $cfg, $cfb, $cro);
imagecopy($identicon, $corner, 0, 0, 0, 0, $spriteZ, $spriteZ);
$corner = imagerotate($corner, 90, $bg);
imagecopy($identicon, $corner, 0, $spriteZ * 2, 0, 0, $spriteZ, $spriteZ);
$corner = imagerotate($corner, 90, $bg);
imagecopy($identicon, $corner, $spriteZ * 2, $spriteZ * 2, 0, 0, $spriteZ, $spriteZ);
$corner = imagerotate($corner, 90, $bg);
imagecopy($identicon, $corner, $spriteZ * 2, 0, 0, 0, $spriteZ, $spriteZ);

/* generate side sprites */
$side = getsprite($ssh, $sfr, $sfg, $sfb, $sro);
imagecopy($identicon, $side, $spriteZ, 0, 0, 0, $spriteZ, $spriteZ);
$side = imagerotate($side, 90, $bg);
imagecopy($identicon, $side, 0, $spriteZ, 0, 0, $spriteZ, $spriteZ);
$side = imagerotate($side, 90, $bg);
imagecopy($identicon, $side, $spriteZ, $spriteZ * 2, 0, 0, $spriteZ, $spriteZ);
$side = imagerotate($side, 90, $bg);
imagecopy($identicon, $side, $spriteZ * 2, $spriteZ, 0, 0, $spriteZ, $spriteZ);

/* generate center sprite */
$center = getcenter($xsh, $cfr, $cfg, $cfb, $sfr, $sfg, $sfb, $xbg);
imagecopy($identicon, $center, $spriteZ, $spriteZ, 0, 0, $spriteZ, $spriteZ);

// $identicon=imagerotate($identicon,$angle,$bg);

/* make white transparent */
imagecolortransparent($identicon, $bg);

/* create blank image according to specified dimensions */
$resized = imagecreatetruecolor(AVATAR_SIZE, AVATAR_SIZE);
imageantialias($resized, true);

/* assign white as background */
$bg = imagecolorallocate($resized, 255, 255, 255);
imagefilledrectangle($resized, 0, 0, AVATAR_SIZE, AVATAR_SIZE, $bg);

/* resize identicon according to specification */
imagecopyresampled($resized, $identicon, 0, 0, (imagesx($identicon) - $spriteZ * 3) / 2, (imagesx($identicon) - $spriteZ * 3) / 2, AVATAR_SIZE, AVATAR_SIZE, $spriteZ * 3, $spriteZ * 3);

/* make white transparent */
imagecolortransparent($resized, $bg);

/* and finally, send to standard output */
header("Content-Type: image/png");
imagepng($resized);