update code

vendor/topthink/think-captcha/src/Captcha.php

@@ -211,7 +211,7 @@ class Captcha
             $this->fontttf = $ttfs[array_rand($ttfs)];
         }
 
-        $fontttf = $ttfPath . $this->fontttf;
+        $fontttf = (strpos($this->fontttf, ':/') !== false || strpos($this->fontttf, ':\\') !== false || $this->fontttf[0] === '/') ? $this->fontttf : $ttfPath . $this->fontttf;
 
         // 添加干扰项
         foreach ($this->interfere as $type => $method) {
@@ -229,7 +229,6 @@ class Captcha
             $x     = $this->fontSize * ($index + 1) * ($this->math ? 1 : 1.5);
             $y     = $this->fontSize + mt_rand(10, 20);
             $angle = $this->math ? 0 : mt_rand(-40, 40);
-
             imagettftext($this->im, (int) $this->fontSize, $angle, (int) $x, (int) $y, $this->color, $fontttf, $char);
         }