php上传图片生成缩略图（GD库）

5年以前 | 阅读数：778 次 | 编程语言：PHP

首先来一段简单的php上传图片生成缩略图的详细代码，分享给大家供大家参考，具体内容如下


    <?php
    function createThumbnail($imageDirectory, $imageName, $thumbDirectory, $thumbWidth, $quality){
    $details = getimagesize("$imageDirectory/$imageName") or die('Please only upload images.');
    $type = preg_replace('@^.+(?<=/)(.+)$@', '$1', $details['mime']);
    eval('$srcImg = imagecreatefrom'.$type.'("$imageDirectory/$imageName");');
    $thumbHeight = $details[1] * ($thumbWidth / $details[0]);
    $thumbImg = imagecreatetruecolor($thumbWidth, $thumbHeight);
    imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $thumbWidth, $thumbHeight,
    $details[0], $details[1]);
    eval('image'.$type.'($thumbImg, "$thumbDirectory/$imageName"'.
    (($type=='jpeg')?', $quality':'').');');
    imagedestroy($srcImg);
    imagedestroy($thumbImg);
    }
    foreach ($_FILES["pictures"]["error"] as $key => $error) {
    if ($error == UPLOAD_ERR_OK) {
    $tmp_name = $_FILES["pictures"]["tmp_name"][$key];
    $name = $_FILES["pictures"]["name"][$key];
    move_uploaded_file($tmp_name, "data/$name");
    createThumbnail("/location/of/main/image", $name, "/location/to/store/thumb", 120, 80);
    //120 = thumb width :: 80 = thumb quality (1-100)
    }
    }
    ?>

接下来再为大家推荐一个实例php使用GD库上传图片以及创建缩略图，直接看代码：

GD库是PHP进行图象操作一个很强大的库。

先在php.ini里增加一行引用：extension=php_gd2.dll

重启apache，做一个测试页var_dump(gd_info());输出数据表明GD库引用成功。

图片上传页面 upload.html


    <html>
    <head>
    <meta http-equiv='Content-Type' content='text/html; charset=utf-8'>
    <title>图片上传</title>
    </head>
    <body>
    <h1>文件上传(只允许上传jpg类型图片)</h1>
    <form enctype="multipart/form-data" action="upload_img.php" method="post">
     <input name="upfile" type="file"><br><br>
     <input type="submit" value="提交">
    </form>
    </body>
    </html>

处理页面upload_img.php


    <?php
     //上传图片保存地址
     $uploadfile = "upfiles/".$_FILES['upfile']['name'];
     //缩略图保存地址
     $smallfile = "upfiles/small_".$_FILES['upfile']['name'];


     if($_FILES['upfile']['type'] != "image/jpeg")
     {
      echo '文件类型错误';
     }
     else
     {
      move_uploaded_file($_FILES['upfile']['tmp_name'],$uploadfile); //上传文件

      $dstW=200;//缩略图宽
      $dstH=200;//缩略图高

      $src_image=ImageCreateFromJPEG($uploadfile);
      $srcW=ImageSX($src_image); //获得图片宽
      $srcH=ImageSY($src_image); //获得图片高

      $dst_image=ImageCreateTrueColor($dstW,$dstH);
      ImageCopyResized($dst_image,$src_image,0,0,0,0,$dstW,$dstH,$srcW,$srcH);
      ImageJpeg($dst_image,$smallfile);

      echo '文件上传成功<br>';
      echo "<img src='$smallfile' />";
     }
    ?>

希望对大家学习php程序设计有所帮助，谢谢大家的支持。