Question

我想知道为什么这个脚本生成的图像中的字符与为会话设置的字符不匹配。我不知道为什么会这样，如果有人可以提供帮助，那就太好了。谢谢，Lea。

// Font directory + font name
$font = 'wordpress/wp-content/themes/boldy/fonts/SF Juggernaut Bold.ttf';
// Total number of lines
$lineCount = 20;
// Size of the font
$fontSize = 19;
// Height of the image
$height = 38;
// Width of the image
$width = 120;
$img_handle = imagecreate ($width, $height) or die ("Cannot Create image");
// Set the Background Color RGB
$backColor = imagecolorallocate($img_handle, 242, 242, 242);
// Set the Line Color RGB
$lineColor = imagecolorallocate($img_handle, 207, 207, 207);
// Set the Text Color RGB
$txtColor = imagecolorallocate($img_handle, 95, 95, 95);

// Generate
$string = "bcdefghijklmopqrstwxyz023456789";
for($i=0;$i<6;$i++){
    $pos = rand(0,36);
    $str .= $string{$pos};
}

$textbox = imagettfbbox($fontSize, 0, $font, $str) or die('Error in imagettfbbox function');

$x = ($width - $textbox[4])/2;
$y = ($height - $textbox[5])/2;

imagettftext($img_handle, $fontSize, 0, $x, $y, $txtColor, $font , $str) or die('Error in imagettftext function');

for($i=0;$i<$lineCount;$i++){
    $x1 = rand(0,$width);$x2 = rand(0,$width);
    $y1 = rand(0,$width);$y2 = rand(0,$width);
    imageline($img_handle,$x1,$y1,$x2,$y2,$lineColor);
}

header('Content-Type: image/jpeg');
imagejpeg($img_handle,NULL,100);
imagedestroy($img_handle);

session_start();
$_SESSION['img_number'] = $str;

更新：测试后我注意到第一次加载图片时，会话未设置，因此刷新图像时，会话设置为最后一个$ str值

Answer 1

如果您的标头已经发送，则可能无法调用session_start（）。

更改

header('Content-Type: image/jpeg');
imagejpeg($img_handle,NULL,100);
imagedestroy($img_handle);

session_start();
$_SESSION['img_number'] = $str;

要

session_start();
header('Content-Type: image/jpeg');
imagejpeg($img_handle,NULL,100);
imagedestroy($img_handle);

$_SESSION['img_number'] = $str;

Answer 2

如果您使用firebug或devtools之类的东西调试脚本，那么它会调用您的图像两次。

尝试禁用您的firebug / devtools，您将看到PROFIT。

Answer 3

session_start();

// Font directory + font name
$font = 'wordpress/wp-content/themes/boldy/fonts/SF Juggernaut Bold.ttf';
// Total number of lines
$lineCount = 20;
// Size of the font
$fontSize = 19;
// Height of the image
$height = 38;
// Width of the image
$width = 120;
$img_handle = imagecreate ($width, $height) or die ("Cannot Create image");
// Set the Background Color RGB
$backColor = imagecolorallocate($img_handle, 242, 242, 242);
// Set the Line Color RGB
$lineColor = imagecolorallocate($img_handle, 207, 207, 207);
// Set the Text Color RGB
$txtColor = imagecolorallocate($img_handle, 95, 95, 95);

// Generate
$string = "bcdefghijklmopqrstwxyz023456789";
$str = '';
for($i=0;$i<6;$i++){
    $pos = rand(0,36);
    $str .= substr($string, $pos, 1);
}

$_SESSION['img_number'] = $str;

$textbox = imagettfbbox($fontSize, 0, $font, $str) or die('Error in imagettfbbox function');

$x = ($width - $textbox[4])/2;
$y = ($height - $textbox[5])/2;

imagettftext($img_handle, $fontSize, 0, $x, $y, $txtColor, $font , $str) or die('Error in imagettftext function');

for($i=0;$i<$lineCount;$i++){
    $x1 = rand(0,$width);$x2 = rand(0,$width);
    $y1 = rand(0,$width);$y2 = rand(0,$width);
    imageline($img_handle,$x1,$y1,$x2,$y2,$lineColor);
}

header('Content-Type: image/jpeg');
imagejpeg($img_handle,NULL,100);
imagedestroy($img_handle);

Session与图像PHP不匹配

3 个答案: