Problema .PNG resizing

[the blader]

Salve ragazzi!
Sto cercando di ridimensionare una png/gif 640*100 a 320*50. Ho il seguente codice:

$allowed_type = array("image/jpeg","image/pjpeg", "image/gif", "image/x-png", "image/png");    $type = $_FILES["image_upload_box"]["type"];        
$type = $_FILES["image_upload_box"]["type"];                
list($image_width, $image_height) = getimagesize($_FILES["image_upload_box"]["tmp_name"]);

if (in_array($type, $allowed_type) && ($_FILES["image_upload_box"]["size"] < 4000000) && ($image_width == 640) && ($image_height == 100)) {
  
if($_FILES["image_upload_box"]["type"] == "image/jpeg" || $_FILES["image_upload_box"]["type"] == "image/pjpeg"){                $image_source = imagecreatefromjpeg($_FILES["image_upload_box"]["tmp_name"]);        }                

if($_FILES["image_upload_box"]["type"] == "image/gif"){                
$image_source = imagecreatefromgif($_FILES["image_upload_box"]["tmp_name"]);        }
if($_FILES["image_upload_box"]["type"] == "image/bmp"){
                $image_source = imagecreatefromwbmp($_FILES["image_upload_box"]["tmp_name"]);        }                    
if($_FILES["image_upload_box"]["type"] == "image/png" || $_FILES["image_upload_box"]["type"] == "image/x-png"){
            $image_source = imagecreatefrompng($_FILES["image_upload_box"]["tmp_name"]);        }        
 
$remote_file = "image_files/".rand(0,10000).$_FILES["image_upload_box"]["name"];        

imagejpeg($image_source,$remote_file,100);        
chmod($remote_file,0644);        
                                    $new_width = 320;            
$new_height = 50;                                    
$new_image = imagecreatetruecolor($new_width , $new_height);            
$image_source = imagecreatefromjpeg($remote_file);                        

imagecopyresampled($new_image, $image_source, 0, 0, 0, 0, $new_width, $new_height, $image_width, $image_height);            
imagejpeg($new_image,$remote_file,100);                        
imagedestroy($new_image);                        
imagedestroy($image_source);                
        $resized_name = basename($remote_file); 

Purtroppo però, sebbene funzioni perfettamente con immagini jpg, quando cerco di ridimensionare gif o png, mi restituisce un'immagine nera.

Ho già provato ad usare diverse soluzioni trovate nel forum, ma non riesco ad implementarle nel codice sopra. Avete qualche idea?

Grazie mille a chi mi aiuterà!!!

[Alhazred]

L'immagine png ha delle parti trasparenti? Di solito dipende da questo.
Prova a cercare qualcosa riguardo il mantenere la trasparenza dei file png elaborandoli con PHP.

P.S. Prima di confermare l'invio del post, visualizza l'anteprima e se necessario, adesso lo sarebbe stato, riiformatta il codice correttamente, così è un po' un casino leggerlo.

[the blader]

Ciao Alhazred! Scusa, hai ragione, ora dovrebbe essere meglio:

$allowed_type = array("image/jpeg","image/pjpeg", "image/gif", "image/x-png", "image/png");
    $type = $_FILES["image_upload_box"]["type"];
    
    
            // get width and height of original image
    list($image_width, $image_height) = getimagesize($_FILES["image_upload_box"]["tmp_name"]);
 
$OS = $_POST['OS'];
$pub_name = $_POST['pub_name'];
$lang = $_POST['lang'];








    // file needs to be jpg,gif,bmp,x-png, 4 MB max and width 320,640.
    if (in_array($type, $allowed_type) && ($_FILES["image_upload_box"]["size"] < 4000000) && ($image_width == 640) && ($image_height == 100)) {


  


        
        // if uploaded image was JPG/JPEG
        if($_FILES["image_upload_box"]["type"] == "image/jpeg" || $_FILES["image_upload_box"]["type"] == "image/pjpeg"){    
            $image_source = imagecreatefromjpeg($_FILES["image_upload_box"]["tmp_name"]);
        }        
        // if uploaded image was GIF
        if($_FILES["image_upload_box"]["type"] == "image/gif"){    
            $image_source = imagecreatefromgif($_FILES["image_upload_box"]["tmp_name"]);
        }    
        // BMP doesn't seem to be supported so remove it form above image type test (reject bmps)    
        // if uploaded image was BMP
        if($_FILES["image_upload_box"]["type"] == "image/bmp"){    
            $image_source = imagecreatefromwbmp($_FILES["image_upload_box"]["tmp_name"]);
        }            
        // if uploaded image was PNG
        if($_FILES["image_upload_box"]["type"] == "image/png" || $_FILES["image_upload_box"]["type"] == "image/x-png"){
            $image_source = imagecreatefrompng($_FILES["image_upload_box"]["tmp_name"]);
        }
        


    
        
        $remote_file = "image_files/".rand(0,10000).$_FILES["image_upload_box"]["name"];
        imagejpeg($image_source,$remote_file,100);
        chmod($remote_file,0644);
    
    


    
        
            
            $new_width = 320;
            $new_height = 50;
            
            
            $new_image = imagecreatetruecolor($new_width , $new_height);
            $image_source = imagecreatefromjpeg($remote_file);
            


            
            imagecopyresampled($new_image, $image_source, 0, 0, 0, 0, $new_width, $new_height, $image_width, $image_height);
            imagejpeg($new_image,$remote_file,100);
            
            imagedestroy($new_image);
                
        imagedestroy($image_source);
        
        //final file name
        $resized_name = basename($remote_file); 

Ho trovato alcune soluzioni, tipo imagesavealpha(), ma non so in che parte del codice dovrei inserirla.
Il problema persiste solo con le immagini trasparenti, ma la maggiore utilità dello script dovrebbe essere proprio con queste ultime. Qualche idea?

[the blader]

Raga, ho trovato una funzione che fa al caso mio. L'ho quindi adattata alle mie esigenze, ma ho un piccolo problema, non so come dare un nome dinamico al nuovo file creato. Sto ancora imparando ad utilizzare le funzioni, so che è sicuramente qualcosa di semplicissimo, ma non riesco:

function resizeImage( $file, $width = 0, $height = 0, $proportional = false, $output = 'file') {
    
$info = getimagesize($file);    $image = '';    
$final_width = 0;    $final_height = 0;    
list($width_old, $height_old) = $info;    
if ($proportional) {        
if ($width == 0) $factor = $height/$height_old;        
elseif ($height == 0) $factor = $width/$width_old;        
else $factor = min ( $width / $width_old, $height / $height_old);          
$final_width = round ($width_old * $factor);        
$final_height = round ($height_old * $factor);    }    
else {    if (($width_old == 320) && ($height_old == 50)){        
$final_width = 320;        
$final_height = 50;    }
elseif(($width_old == 640) && ($height_old == 100)){        
$final_width = 320;        
$final_height = 50;    }
           }    
switch ( $info[2] ) {        
case IMAGETYPE_GIF:            $image = imagecreatefromgif($file);        break;        
case IMAGETYPE_JPEG:            $image = imagecreatefromjpeg($file);        break;        case IMAGETYPE_PNG:         $image = imagecreatefrompng($file);        break;        
default:            return false;    }            
$image_resized = imagecreatetruecolor( $final_width, $final_height );                
if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) {        
$trnprt_indx = imagecolortransparent($image);
        if ($trnprt_indx >= 0) {            
$trnprt_color    = imagecolorsforindex($image, $trnprt_indx);            
$trnprt_indx    = imagecolorallocate($image_resized, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);            
imagefill($image_resized, 0, 0, $trnprt_indx);            
imagecolortransparent($image_resized, $trnprt_indx);        }         
elseif ($info[2] == IMAGETYPE_PNG) {            
imagealphablending($image_resized, false);            
$color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);            
imagefill($image_resized, 0, 0, $color);            
imagesavealpha($image_resized, true);        
}    
}    
imagecopyresampled($image_resized, $image, 0, 0, 0, 0, $final_width, $final_height, $width_old, $height_old);                
switch ( strtolower($output) ) {        
case 'browser':            $mime = image_type_to_mime_type($info[2]);            
header("Content-type: $mime");            
$output = NULL;        break;        
case 'file':            
$output = $file;        
break;        
case 'return':            
return $image_resized;        break;        
default:        break;    }    
switch ( $info[2] ) {        
case IMAGETYPE_GIF:            imagegif($image_resized, $output);        break;        
case IMAGETYPE_JPEG:            imagejpeg($image_resized, $output);        break;        
case IMAGETYPE_PNG:            imagepng($image_resized, $output);        break;        
default:            return false;    }    
return true;}

$test = $_FILES["image_upload_box"]["tmp_name"];
resizeImage($test, "320", "50", false, "image_files/prova.gif");
echo '<img src="image_files/prova.gif">'; 

La parte che mi interessa è questa:
resizeImage($test, "320", "50", false, "image_files/prova.gif");
come faccio a chiamare la nuova immagine con qualcosa tipo: "images/".rand(0,100).$_FILES["image_upload_box"]["name"];

Spero possiate aiutarmi!