在php中上传时出现黑色图像

Question

Upload, at the front end, seems to work and although all the files are created successfully, they are all completely black. I'm sure it's something simple I am doing wrong but I've been staring at it for a while and I'm just not getting it.

I'm also untrained in php and I am trying to teach myself along the way.

I have been resizing the images proportionally and some of the widths and heights do have real numbers, does this make a difference? Should I round them to the nearest pixel?

Below is the section of code where the error is occurring. I think I know the line that is causing the issues, so I have marked it with "//error".

//Resize proportionally
for($i=0;$i<$image_count;$i++){
    $size = getimagesize($_FILES["fileToUpload"]["tmp_name"][$i]);
    $ratio = $size[0]/$size[1]; // width/height
    echo "<BR>Original width = ".$size[0]." Original height = ".$size[1]."<BR>";
    if( $ratio > 1) {
        $width = 500;
        $height = 500/$ratio;
    }
    else {
        $width = 500*$ratio;
        $height = 500;
    }
    echo "<BR>new width = ".$width." new height = ".$height."<BR>";
    // resample
    $image_p[$i] = imagecreatetruecolor($width, $height);
    $image[$i] = imagecreatefromjpeg($_FILES["fileToUpload"]["tmp_name".$i][$i]); //error
    imagecopyresampled($image_p[$i], $image[$i], 0, 0, 0, 0, $width, $height, $size[0], $size[1]);
    //echo "<BR>image".$i." has been resized and resampled";
}

I've also edited my php.ini file to include the following.

1.  ; Maximum size of POST data that PHP will accept.  
2.  post_max_size = 700M  
3.    
4.  ; Maximum number of files. Added by DJ  
5.  max_file_uploads=500  
6.    
7.  ; Maximum allowed size for uploaded files. Added by DJ  
8.  upload_max_filesize = 50M  

Any help would be appreciated.

Answer 1

Initially I wasn't sure about the intended end for the script as the code posted was only a portion but if I have now understood correctly then the image processing has the end goal of saving a modified version of the uploaded file?

<?php
    define('KB',1024);
    define('MB',pow(KB,2));
    define('GB',pow(KB,3));
    define('TB',pow(KB,4));


    function uploaderror( $error ){ 
        switch( $error ) { 
            case UPLOAD_ERR_INI_SIZE: return "The uploaded file exceeds the upload_max_filesize directive in php.ini"; 
            case UPLOAD_ERR_FORM_SIZE: return "The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form"; 
            case UPLOAD_ERR_PARTIAL: return "The uploaded file was only partially uploaded"; 
            case UPLOAD_ERR_NO_FILE: return "No file was uploaded"; 
            case UPLOAD_ERR_NO_TMP_DIR: return "Missing a temporary folder"; 
            case UPLOAD_ERR_CANT_WRITE: return "Failed to write file to disk"; 
            case UPLOAD_ERR_EXTENSION: return "File upload stopped by extension"; 
            default: return "Unknown upload error";
        }
    }
    function size( $i ) {
        if ( is_numeric( $i ) ) {
            if( $i > 0 && $i < KB ) {
                return "{$i} bytes";
            } elseif( $i >= KB && $i < MB ) {
                return round( ( $i / KB ),2 )."Kb";
            } elseif( $i >= MB && $i < GB ) {
                return round( ( $i / MB ),2 )."Mb";
            } elseif( $i >= GB && $i < TB ) {
                return round( ( $i / GB ),2 )."Gb";
            } elseif( $i >= TB ) {
                return round( ( $i / TB ),2 )."Tb";
            } else {
                #Computer will die
            }
        }
    }

    if( $_SERVER['REQUEST_METHOD']=='POST' && !empty( $_FILES ) ){

        $errors=array();
        $feedback=array();

        /* maximum width or height */
        $maxdim=500;

        /* Obtain reference to files collection */
        $files=(object)$_FILES['fileToUpload'];

        /* location images will be saved to */
        $outputdir='c:/temp/fileuploads/2/';

        /* Process all files */
        if( count( $files->name ) > 1 ){

            /* Iterate through files collection */
            foreach( $files->name as $i => $void ){
                try{

                    $name = $files->name[$i];
                    $size = size( $files->size[$i] );
                    $type = $files->type[$i];
                    $tmp  = $files->tmp_name[$i];
                    $error= $files->error[$i];

                    /* save the file as */
                    $filename = $outputdir . $name;


                    if( !$error == UPLOAD_ERR_OK or !is_uploaded_file( $tmp ) ) throw new Exception( uploaderror( $error ) );
                    else {

                        list( $w, $h, $t, $a ) = getimagesize( $tmp );
                        $ratio = $w / $h;

                        if( $ratio==1 ){
                            $width=$height=$maxdim;
                        } else {
                            $width=ceil( $maxdim * $ratio );
                            $height=$maxdim;
                        }

                        $target=imagecreatetruecolor( $width, $height );
                        $source=imagecreatefromjpeg( $tmp );
                        $result=imagecopyresampled( $target, $source, 0, 0, 0, 0, $width, $height, $w, $h );

                        if( $result ){
                            /* save the modified image to disk */
                            $status=imagejpeg( $target, $filename );
                            $newsize = size( filesize( $filename ) );

                            /* free resources */
                            imagedestroy( $target );
                            imagedestroy( $source );

                            /* delete uploaded temp file */
                            @unlink( $tmp );

                            if( !$status )throw new Exception( 'Unable to save ' . $filename );
                            else $feedback[]="Success: '{$name}' saved as '{$filename}' was {$size} now {$newsize} - resized from dimensions [ W:{$w}, H:{$h} ] to [ W:{$width}, H:{$height} ] ";
                        }
                    }


                }catch( Exception $e ){
                    $errors[]=$e->getMessage();
                    continue;
                }
            }
            if( !empty( $errors ) ) echo '<pre>',print_r($errors,true),'</pre>';
            if( !empty( $feedback ) ) echo '<pre>',print_r($feedback,true),'</pre>';
        }
    }
?>