PHP图像缩放不起作用

Question

“res.php”下面提供的脚本旨在缩放图像，然后在 html 页面的 HEADER css 中使用。根据“CID”（俱乐部 ID）调用图像。每个俱乐部都有存储在数据库中的信息，包括名为 club_header 的信息。 club_header 是一个 VARCHAR，用于存储图像的绝对位置（文件系统或 Web）。 “res.php”功能是调用图像并将其输出到浏览器以及将图像重新调整为任何设置的大小。默认设置为 960 x 200。

但是由于某种原因，脚本没有做它必须做的事情，而是输出了一个损坏的图像。代码可能有什么问题？

如果需要一些服务器 + php 信息

服务器： Apache v2.2.21、PHP v5.3.8、SQL v5.5.16、GD v2.0.34

PHP.ini： max_execution_time = 300，max_input_time = 60，memory_limit = 208M，post_max_size = 24M

“res.php”源代码

require("php/db.class.php");

function scaleImageFileToBlob($file) {

    $file = $_GET['cid'];

    $query = mysql_query("SELECT * FROM clubs WHERE club_id = '".$_GET['cid']."'");
    $obj = mysql_fetch_array($query);
    $photoObj = $obj['club_header'];

    $source_pic = $photoObj;
    $max_width = 960;
    $max_height = 200;

    list($width, $height, $image_type) = getimagesize($file);

    switch ($image_type)
    {
        case 1: $src = imagecreatefromgif($file); break;
        case 2: $src = imagecreatefromjpeg($file);  break;
        case 3: $src = imagecreatefrompng($file); break;
        default: return '';  break;
    }

    $x_ratio = $max_width / $width;
    $y_ratio = $max_height / $height;

    if( ($width <= $max_width) && ($height <= $max_height) ){
        $tn_width = $width;
        $tn_height = $height;
        }elseif (($x_ratio * $height) < $max_height){
            $tn_height = ceil($x_ratio * $height);
            $tn_width = $max_width;
        }else{
            $tn_width = ceil($y_ratio * $width);
            $tn_height = $max_height;
    }

    $tmp = imagecreatetruecolor($tn_width,$tn_height);

    /* Check if this image is PNG or GIF, then set if Transparent*/
    if(($image_type == 1) OR ($image_type==3))
    {
        imagealphablending($tmp, false);
        imagesavealpha($tmp,true);
        $transparent = imagecolorallocatealpha($tmp, 255, 255, 255, 127);
        imagefilledrectangle($tmp, 0, 0, $tn_width, $tn_height, $transparent);
    }
    imagecopyresampled($tmp,$src,0,0,0,0,$tn_width, $tn_height,$width,$height);

    /*
     * imageXXX() only has two options, save as a file, or send to the browser.
     * It does not provide you the oppurtunity to manipulate the final GIF/JPG/PNG file stream
     * So I start the output buffering, use imageXXX() to output the data stream to the browser, 
     * get the contents of the stream, and use clean to silently discard the buffered contents.
     */
    ob_start();

    switch ($image_type)
    {
        case 1: imagegif($tmp); break;
        case 2: imagejpeg($tmp, NULL, 100);  break; // best quality
        case 3: imagepng($tmp, NULL, 0); break; // no compression
        default: echo ''; break;
    }

    $final_image = ob_get_contents();

    ob_end_clean();

    return $final_image;

}

echo scaleImageFileToBlob($file);

提前谢谢你。

Answer 1

您可能需要在图像输出之前发送正确的标头，例如

header('Content-Type: image/png');

header('Content-Type: image/jpeg');

header('Content-Type: image/gif');