PHP 图像大小调整

Question

我有一个脚本，可以将文件上传到服务器并将文件名添加到数据库中，但我想要在上传之前限制图像的最大尺寸。因此，如果我上传 1000 x 500 的图像，它将受到限制，但仍保留其尺寸，并将更改为 200 x 100，但 300 x 300 的图像将被限制为 200 x 200

    <?php 

     //This is the directory where images will be saved 
     $target = "uploads/"; 
     $target = $target . basename( $_FILES['photo']['name']); 

     //This gets all the other information from the form 
     $name=$_POST['name']; 
     $pic=($_FILES['photo']['name']); 

     // Connects to your Database 
     mysql_connect("hostname", "username", "password") or die(mysql_error()) ; 
     mysql_select_db("database") or die(mysql_error()) ; 

     //Writes the information to the database 
     mysql_query("INSERT INTO `table` (name, photo) VALUES ('$name','$pic')") ; 

     //Writes the photo to the server 
     if(move_uploaded_file($_FILES['photo']['tmp_name'], $target)) 
     { 

     //Tells you if its all ok 
     echo "The file ". basename( $_FILES['uploadedfile']['name']). " has been uploaded"; 
     } 
     else { 

     //Gives and error if its not 
     echo "Sorry, there was a problem uploading your file."; 
     } 
     ?> 

感谢您的帮助

Answer 1

据我所知，您无法在上传图像之前调整图像大小。 （我可能是错的！）但是，当您上传图像时，它会进入临时文件。您可以调整临时图像的大小并将调整大小的图像复制到其最终目的地。

由于（似乎）您希望保持宽度恒定，因此您实际上不需要进行大量比率测试。

更新：

您应该能够简单地使用它来代替原始代码。大部分都没有改变。

<?php

// resizes an image to fit a given width in pixels.
// works with BMP, PNG, JPEG, and GIF
// $file is overwritten
function fit_image_file_to_width($file, $w, $mime = 'image/jpeg') {
    list($width, $height) = getimagesize($file);
    $newwidth = $w;
    $newheight = $w * $height / $width;
    
    switch ($mime) {
        case 'image/jpeg':
            $src = imagecreatefromjpeg($file);
            break;
        case 'image/png';
            $src = imagecreatefrompng($file);
            break;
        case 'image/bmp';
            $src = imagecreatefromwbmp($file);
            break;
        case 'image/gif';
            $src = imagecreatefromgif($file);
            break;
    }
    
    $dst = imagecreatetruecolor($newwidth, $newheight);
    imagecopyresampled($dst, $src, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
    
    switch ($mime) {
        case 'image/jpeg':
            imagejpeg($dst, $file);
            break;
        case 'image/png';
            imagealphablending($dst, false);
            imagesavealpha($dst, true);
            imagepng($dst, $file);
            break;
        case 'image/bmp';
            imagewbmp($dst, $file);
            break;
        case 'image/gif';
            imagegif($dst, $file);
            break;
    }
    
    imagedestroy($dst);
}

// init file vars
$pic  = $_FILES['photo']['name'];
$target = 'uploads/' . basename( $_FILES['photo']['name']);
$temp_name = $_FILES['photo']['tmp_name'];
$type = $_FILES["photo"]["type"];

// Connects to your Database 
mysql_connect("hostname", "username", "password") or die(mysql_error()) ; 
mysql_select_db("database") or die(mysql_error()) ; 

// get form data
$name = mysql_real_escape_string(isset($_POST['name']) ? $_POST['name'] : 'No name');

//Writes the information to the database 
mysql_query("INSERT INTO `table` (name, photo) VALUES ('$name','$pic')") ; 

// resize the image in the tmp directorys
fit_image_file_to_width($temp_name, 200, $type);

//Writes the photo to the server
if(move_uploaded_file($temp_name, $target)) {

    //Tells you if its all ok 
    echo "The file ". basename( $_FILES['photo']['name'] ). " has been uploaded"; 

} else {

    //Gives and error if its not 
    echo "Sorry, there was a problem uploading your file."; 

}

?>

Answer 2

我过去使用这个函数来生成适合给定尺寸并保持纵横比的缩略图，也许您可​​以以某种方式使用它：

function resize_img_nofill($src_name,$dst_name,$width,$height,$dontExpand=false) {
        $MAGIC_QUOTES = set_magic_quotes_runtime();
        set_magic_quotes_runtime(0);

        $type =  strtolower(substr(strrchr($src_name,"."),1));

        if($type == "jpg") {
            $src = imagecreatefromjpeg($src_name);
        } else if($type == "png") {
            $src = imagecreatefrompng($src_name);    
        } else if($type == "gif") {
            $src = imagecreatefromgif($src_name);    
        } else {
                if($src_name != $dst_name) copy($src_name,$dst_name);
                set_magic_quotes_runtime($MAGIC_QUOTES);
                return;
        }



        $d_width = $s_width = imagesx($src);
        $d_height = $s_height = imagesy($src);

        if($s_width*$height > $width*$s_height && (!$dontExpand || $width < $s_width)) {
            $d_width = $width;
            $d_height = (int)round($s_height*$d_width/$s_width);
        } else if(!$dontExpand || $height < $s_height) {
            $d_height = $height;
            $d_width = (int)round($s_width*$d_height/$s_height);
        }

        if($s_width != $d_width || $s_height != $d_height) {

                if($type == "jpg") {
                        $dst = imagecreatetruecolor($d_width,$d_height);
                } else if($type == "png") {
                $dst = imagecreate($d_width,$d_height);
                } else if($type == "gif") {
                $dst = imagecreate($d_width,$d_height);
                } 

                $white = imagecolorallocate($dst,255,255,255);
                imagefilledrectangle($dst,0,0,$d_width,$d_height,$white);
                imagecopyresampled($dst,$src,0,0,0,0,$d_width,$d_height,$s_width,$s_height);

                if($type == "jpg") 
                imagejpeg($dst,$dst_name, 80);  
                else if($type == "png")
                imagepng($dst,$dst_name);       
                else if($type == "gif")
                imagegif($dst,$dst_name);       

                imagedestroy($dst);
                imagedestroy($src);
        } else {
                copy($src_name,$dst_name);
        }


        set_magic_quotes_runtime($MAGIC_QUOTES);
        return array($d_width,$d_height);
}