调整PHP图像大小

Question

我有一个上传文件到服务器以及添加文件名到数据库的脚本，但我想要做的是在上传之前限制图像的最大尺寸。因此，如果我上传的图像是1000 x 500，它将受到限制，但仍将保持其尺寸，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."; 
     } 
     ?> 

谢谢你的帮忙

Answer 1

据我所知，你不能在上传之前调整图片的大小。(我可能错了！)但是，当您上传图像时，它会变成一个临时文件。您可以调整临时图像的大小，并将调整后的图像复制到其最终目标。

这段代码改编自FliquidStudios：Resizing images in PHP with GD and Imagick上的一段代码。

既然(看起来)你想保持宽度不变，你实际上不需要做很多比率测试。

更新：

您应该能够简单地使用它来代替您的原始代码。它的大部分是不变的。

<?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

我在过去使用这个函数来生成适合给定尺寸的缩略图，保持纵横比，也许你可以使用它：

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);
}