Unable to create thumb, image is black

Question

Am uploading Multiple image from single input and create thumb form all uploaded image on fly But when i run code i get only black image but orginal image is same as upl

Answer 1

Problem

The problem is located in the following line:

imagecopyresampled($dimg, $simg, -$int_width, 0, 0, 0, $adjusted_width, $nh, $w, $h);

Why are you using a negative value as destination's x? Your source image is actually put at the left of your target image, so your target image appears empty.

Solution

I invite you to use the following function to resize your image:

function resizePreservingAspectRatio($img, $targetWidth, $targetHeight)
{
   $srcWidth = imagesx($img);
   $srcHeight = imagesy($img);

   // Determine new width / height preserving aspect ratio
   $srcRatio = $srcWidth / $srcHeight;
   $targetRatio = $targetWidth / $targetHeight;
   if (($srcWidth <= $targetWidth) && ($srcHeight <= $targetHeight))
   {
      $imgTargetWidth = $srcWidth;
      $imgTargetHeight = $srcHeight;
   }
   else if ($targetRatio > $srcRatio)
   {
      $imgTargetWidth = (int) ($targetHeight * $srcRatio);
      $imgTargetHeight = $targetHeight;
   }
   else
   {
      $imgTargetWidth = $targetWidth;
      $imgTargetHeight = (int) ($targetWidth / $srcRatio);
   }

   // Creating new image with desired size
   $targetImg = imagecreatetruecolor($targetWidth, $targetHeight);

   // Add transparency if your reduced image does not fit with the new size
   $targetTransparent = imagecolorallocate($targetImg, 255, 0, 255);
   imagefill($targetImg, 0, 0, $targetTransparent);
   imagecolortransparent($targetImg, $targetTransparent);

   // Copies image, centered to the new one (if it does not fit to it)
   imagecopyresampled(
      $targetImg, $img, ($targetWidth - $imgTargetWidth) / 2, // centered
      ($targetHeight - $imgTargetHeight) / 2, // centered
      0, 0, $imgTargetWidth, $imgTargetHeight, $srcWidth, $srcHeight
   );

   return $targetImg;
}

Implementation

 $tmp_name)
   {
      $file_name = $key . $_FILES['files']['name'][$key];
      $file_size = $_FILES['files']['size'][$key];
      $file_tmp = $_FILES['files']['tmp_name'][$key];
      $file_type = $_FILES['files']['type'][$key];
      if ($file_size > 2097152000)
      {
         $errors[] = 'File size must be less than 2 MB';
      }
      $desired_dir = "user_data/";
      if (empty($errors) == true)
      {
         if (is_dir($desired_dir) == false)
         {
            mkdir("$desired_dir", 0700);        // Create directory if it does not exist
         }
         if (is_dir("$desired_dir/" . $file_name) == false)
         {
            move_uploaded_file($file_tmp, "$desired_dir/" . $newname . $file_name);
         }
         else
         {                                  // rename the file if another one exist
            $new_dir = "$desired_dir/" . $newname . $file_name;
            rename($file_tmp, $new_dir);
         }
      }
      else
      {
         print_r($errors);
      }
   }
   if (empty($error))
   {
      echo "FILE : $file1
";
      echo "FILE : $file2
";
      echo "FILE : $file3
";
      echo "FILE : $file4
";
      echo "FILE : $file5
";
   }
   $orig_directory = "$desired_dir";    //Full image folder
   $thumb_directory = "thumb/";    //Thumbnail folder

   /* Opening the thumbnail directory and looping through all the thumbs: */
   $dir_handle = @opendir($orig_directory); //Open Full image dirrectory
   if ($dir_handle > 1)
   { //Check to make sure the folder opened
      $allowed_types = array ('jpg', 'jpeg', 'gif', 'png');
      $file_type = array ();
      $ext = '';
      $title = '';
      $i = 0;

      while ($file_name = @readdir($dir_handle))
      {
         /* Skipping the system files: */
         if ($file_name == '.' || $file_name == '..')
            continue;

         $file_type = explode('.', $file_name);    //This gets the file name of the images
         $ext = strtolower(array_pop($file_type));

         /* Using the file name (withouth the extension) as a image title: */
         $title = implode('.', $file_type);
         $title = htmlspecialchars($title);

         /* If the file extension is allowed: */
         if (in_array($ext, $allowed_types))
         {

            /* If you would like to inpute images into a database, do your mysql query here */

            /* The code past here is the code at the start of the tutorial */
            /* Outputting each image: */

            $nw = 100;
            $nh = 100;
            $source = "$desired_dir{$file_name}";
            $stype = explode(".", $source);
            $stype = $stype[count($stype) - 1];
            $dest = "thumb/{$file_name}";

            $size = getimagesize($source);
            $w = $size[0];
            $h = $size[1];

            switch ($stype)
            {
               case 'gif':
                  $simg = imagecreatefromgif($source);
                  break;
               case 'jpg':
                  $simg = imagecreatefromjpeg($source);
                  break;
               case 'png':
                  $simg = imagecreatefrompng($source);
                  break;
            }

            $dimg = resizePreservingAspectRatio($simg, $nw, $nh);
            imagepng($dimg, $dest);
         }
      }

      /* Closing the directory */
      @closedir($dir_handle);
   }
}

function resizePreservingAspectRatio($img, $targetWidth, $targetHeight)
{
   $srcWidth = imagesx($img);
   $srcHeight = imagesy($img);

   // Determine new width / height preserving aspect ratio
   $srcRatio = $srcWidth / $srcHeight;
   $targetRatio = $targetWidth / $targetHeight;
   if (($srcWidth <= $targetWidth) && ($srcHeight <= $targetHeight))
   {
      $imgTargetWidth = $srcWidth;
      $imgTargetHeight = $srcHeight;
   }
   else if ($targetRatio > $srcRatio)
   {
      $imgTargetWidth = (int) ($targetHeight * $srcRatio);
      $imgTargetHeight = $targetHeight;
   }
   else
   {
      $imgTargetWidth = $targetWidth;
      $imgTargetHeight = (int) ($targetWidth / $srcRatio);
   }

   // Creating new image with desired size
   $targetImg = imagecreatetruecolor($targetWidth, $targetHeight);

   // Add transparency if your reduced image does not fit with the new size
   $targetTransparent = imagecolorallocate($targetImg, 255, 0, 255);
   imagefill($targetImg, 0, 0, $targetTransparent);
   imagecolortransparent($targetImg, $targetTransparent);

   // Copies image, centered to the new one (if it does not fit to it)
   imagecopyresampled(
      $targetImg, $img, ($targetWidth - $imgTargetWidth) / 2, // centered
      ($targetHeight - $imgTargetHeight) / 2, // centered
      0, 0, $imgTargetWidth, $imgTargetHeight, $srcWidth, $srcHeight
   );

   return $targetImg;
}

?>


   

   

   

   

   

   

Note: I am saving as PNG, as if you want a 100x100 image using a non-square image (such as 800x600), and without breaking its aspect ratio, we should put transparency behind the unused space and JPEG do not support it.