Home > Article > Backend Development > 为什么无法输出一张图片
session_start(); //随机码的个数 //$_rnd_code = 4; //创建随机码 for($i=0;$i<4;$i++){ $_nmsg.=dechex(mt_rand(0,15)); } //保存session $_SESSION['code']=$_nmsg; //长和高 $_width = 75; $_height = 25; //创建一张图像 $_img = imagecreatetruecolor($_width,$_height); //输出图像 header('Content-Type:image/png'); imagepng($_img);
$_nmsg='';
for($i=0;$i $_nmsg.=dechex(mt_rand(0,15));
}
$_nmsg='';
for($i=0;$i $_nmsg.=dechex(mt_rand(0,15));
}
session_start(); //随机码的个数 //$_rnd_code = 4; $_nmsg=' '; //创建随机码 for($i=0;$i<4;$i++){ $_nmsg.=dechex(mt_rand(0,15)); } //保存session $_SESSION['code']=$_nmsg; //长和高 $_width = 75; $_height = 25; //创建一张图像 $_img = imagecreatetruecolor($_width,$_height); //白色 $_white = imagecolorallocate($_img,255,255,255); //填充 imagefill($_img,0,0,$_white); $_flag = false; if($_flag){ //黑色边框 $_black = imagecolorallocate($_img,0,0,0); imagerectangle($_img,0,0,$_width-1,$_height-1,$_black); } //随机画出6个线条 for($i=0;$i<6;$i++){ $_rnd_color = imagecolorallocate($_img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255)); imageline($_img,mt_rand(0,$_width),mt_rand(0,$_height),mt_rand(0,$_width),mt_rand(0,$_height),$_rnd_color); } //随机雪花 for($i=0;$i<100;$i++){ $_rnd_color = imagecolorallocate($_img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)); imagestring($_img,1,mt_rand(1,$_width),mt_rand(1,$_height),'*',$_rnd_color); } //输出验证码 for($i=0;$i<strlen($_SESSION['code']);$i++){ $_rnd_color = imagecolorallocate($_img,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)); imagestring($_img,5,$i*$_width/$_rnd_code+mt_rand(1,10),mt_rand(1,$_heght/2),$_SESSION['code'][$i],$_rnd_color); } //输出图像 header('Content-Type:image/png'); imagepng($_img);
<br /><b>Notice</b>: Undefined variable: _rnd_code in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: Division by zero in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _heght in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: mt_rand(): max(0) is smaller than min(1) in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _rnd_code in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: Division by zero in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _heght in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: mt_rand(): max(0) is smaller than min(1) in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _rnd_code in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: Division by zero in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _heght in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: mt_rand(): max(0) is smaller than min(1) in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _rnd_code in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: Division by zero in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _heght in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: mt_rand(): max(0) is smaller than min(1) in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _rnd_code in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: Division by zero in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Notice</b>: Undefined variable: _heght in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br /><br /><b>Warning</b>: mt_rand(): max(0) is smaller than min(1) in <b>D:\AMP\web\ide_tmp.php</b> on line <b>53</b><br />‰PNG按错误信息修改
将header注释掉,打开错误就可以看到错误。