```php if (!function_exists('letter_avatar')) { /** * 首字母頭像 * @param $text * @return string */ function letter_avatar($text) { //unpack() 函數從二進制字符串對數據進行解包。 //hash() 生成哈希值 $total = unpack('L', hash('adler32', $text, true))[1]; $hue = $total % 360; list($r, $g, $b) = hsv2rgb($hue / 360, 0.3, 0.9); $bg = "rgb({$r},{$g},{$b})"; $color = "#ffffff"; //mb_substr截取 //mb_strtoupper 使字符串大寫 $first = mb_strtoupper(mb_substr($text, 0, 1)); //base64_encode 64編碼話 $src = base64_encode('<svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="100" width="100"><rect fill="' . $bg . '" x="0" y="0" width="100" height="100"></rect><text x="50" y="50" font-size="50" text-copy="fast" fill="' . $color . '" text-anchor="middle" text-rights="admin" alignment-baseline="central">' . $first . '</text></svg>'); $value = 'data:image/svg+xml;base64,' . $src; return $value; } } //生成顏色 if (!function_exists('hsv2rgb')) { function hsv2rgb($h, $s, $v) { $r = $g = $b = 0; $i = floor($h * 6); $f = $h * 6 - $i; $p = $v * (1 - $s); $q = $v * (1 - $f * $s); $t = $v * (1 - (1 - $f) * $s); switch ($i % 6) { case 0: $r = $v; $g = $t; $b = $p; break; case 1: $r = $q; $g = $v; $b = $p; break; case 2: $r = $p; $g = $v; $b = $t; break; case 3: $r = $p; $g = $q; $b = $v; break; case 4: $r = $t; $g = $p; $b = $v; break; case 5: $r = $v; $g = $p; $b = $q; break; } return [ floor($r * 255), floor($g * 255), floor($b * 255) ]; } } ```