为不同的 mime 类型调整 PHP 图像大小

Question

我是一个 php noob 并试图创建一个图像大小调整脚本，将上传的图像缩小到更小的尺寸。使用下面的当前脚本，我可以显示原始图像。新的宽度和高度似乎没有注册。任何帮助表示赞赏。

    <?php

    if ($_SERVER['REQUEST_METHOD']=='POST') {
      if (isset($_FILES['image']['tmp_name'])) {
        if ($_FILES['image']['error']==0){
        $new_dir = '/PHP_MySQL_Practice/uploaded/images';
        $fullpath = $_SERVER['DOCUMENT_ROOT'].$new_dir;
        if(!is_dir($fullpath)) {
            mkdir($fullpath, 0777, TRUE); 
        }
        //get file name and type(extension)
        $name = $_FILES['image']['name'];
        $type = $_FILES['image']['type'];

        //separate image name after first "dot"
        $separated = explode(".", $name);
        //get string before the dot which was stored as the 1st item in the separated array.
        $first = $separated[0];
        //use php function pathinfo to get extension of image file
        $ext = pathinfo($name, PATHINFO_EXTENSION);
        //concatenate current timestamp (to avoid file overwrites) with the extracted file 'firstname' and add the extension
        $name = time().'_'.$first.'.'.$ext;
        $target = $fullpath.'/'.$name;

        if (move_uploaded_file($_FILES['image']['tmp_name'], $target)) {

            resizeImage($target, $name);
            echo '<img src="' . $target . '"/>';

        }

    }
    else {

        echo 'there was an error in saving ur image file.';
    }
}   
else {

    echo 'ur image could not be uploaded.';
}
    }
    else {
    ?>
<form method="POST" enctype="multipart/form-data">
    <label>upload image: </label>
    <input type="file" name="image" />
    <input type="submit" />
</form> 
    <?php   
    }

    //function to resize image
    function resizeImage($dir, $img) {
list($src_w, $src_h) = getimagesize($dir);
$max_w = 150;
$max_h = 150;
if ($src_w > $max_w) {
    $ratio = $max_w / $src_w;
    $new_img_w = $src_w * $ratio;
}
else if ($src_h > $max_h) {
    $ratio = $max_h / $src_h;
    $new_img_h = $src_h * $ratio;
}
$img_mime_type = getimagesize($dir);
switch ($img_mime_type['mime']) {
    case 'image/jpeg':
    case 'image/pjpeg':
        $src = imagecreatefromjpeg($dir);
        return $src;
        break;
    case 'image/gif':
        $src = imagecreatefromgif($dir);
        return $src;
        break;
    case 'image/png':
        $src = imagecreatefrompng($dir);
        return $src;
        break;
    default:
        return FALSE;
        break;
}
$new_img = imagecreatetruecolor($new_img_w, $new_img_h);
imagecopyresampled($new_img, $src, 0, 0, 0, 0, $new_img_w, $new_img_h, $max_w, $max_h);
switch ($img_mime_type['mime']) {
    case 'image/jpeg':
    case 'image/pjpeg':
        imagejpeg($new_img, $dir, 100);
        break;
    case 'image/gif':
        imagegif($new_img, $dir);
        break;
    case 'image/png':
        imagepng($new_img, $dir);
        break;
    default:
        return FALSE;
        break;
}

imagedestroy($src);
imagedestroy($new_img);
    }
    ?>

Answer 1

那里有一些缺陷

imagegif只有 2 个参数 $im并保存位置

imagepng压缩级别从 0 到 9 而不是 100

您没有保存图像，null来自 imagejpeg($new_img, null, 100);应该用 $dir 更改

您最后的功能是 imagdestroy($src);错了，应该是imagedestroy($src);

您的 switch应该是:

switch ($img_mime_type['mime']) {
    case 'image/jpeg':
    case 'image/pjpeg':
        imagejpeg($new_img, $dir, 100);
        break;
    case 'image/gif':
        imagegif($new_img, $dir);
        break;
    case 'image/png':
        imagepng($new_img, $dir);
        break;
    default:
        return FALSE;
        break;
}

您的调整大小功能:

function resizeImage($dir, $img) {
    //echo $dir; die;
    list($src_w, $src_h) = getimagesize($dir);
    $max_w = 150;
    $max_h = 150;
    if ($src_w > $max_w) {
        $ratio = $max_w / $src_w;
        $max_w = $src_w * $ratio;
    }
    else if ($src_h > $max_h) {
        $ratio = $max_h / $src_h;
        $max_h = $src_h * $ratio;
    }
    $img_mime_type = getimagesize($dir);
    $src = imagecreatefromstring(file_get_contents($dir));
    $new_img = imagecreatetruecolor($max_w, $max_h);
    imagecopyresampled($new_img, $src, 0, 0, 0, 0, $max_w, $max_h, $src_w, $src_h);
    switch ($img_mime_type['mime']) {
        case 'image/jpeg':
        case 'image/pjpeg':
            imagejpeg($new_img, $dir, 100);
            break;
        case 'image/gif':
            imagegif($new_img, $dir);
            break;
        case 'image/png':
            imagepng($new_img, $dir);
            break;
        default:
            return FALSE;
            break;
    }

    imagedestroy($src);
    imagedestroy($new_img);
}