[Resolved] Problems trying to create thumbnails

[ppowell]

PHP 4.3.2 with --enable-exif

I have the following class:

<?php

class ThumbGenerator extends MethodGeneratorForActionPerformer {

  function ThumbGenerator() {      // CONSTRUCTOR
    // DO ALL KINDS OF STUFF HERE
  }

  /**
   * This method can only be used if you are using PHP version 4.3+ and if you have TIFF or JPEG image
   *
   * @access private
   */
  function generateTIFFJPEGThumb() {                            // VOID METHOD
        global $section, $thumbLocationPath;
        /*------------------------------------------------------------------------------------------------------------------------------------------
            Because of the different methodologies of each method, the constructor must be called, thus, the class object
            must be initiated.  If "$this" does not exist, trigger an error
        -------------------------------------------------------------------------------------------------------------------------------------------*/
        if (!$this || !is_object($this)) trigger_error('You must first instantiate a ThumbGenerator object to use this method', E_USER_ERROR);

    // STREAM FILE EMBEDDED THUMBNAIL CONTENTS INTO BINARY STRING VARIABLE
    if ($this->isSuccessful) {
     $thumbStreamObj = exif_thumbnail($this->locationPath . '/' . $this->fileName, $width, $height, $mimeTypeInt);
     print_r('<P>thumbStreamObj: '); print_r($thumbStreamObj);
     if (!$thumbStreamObj) {
      $this->isSuccessful = false;
      $this->setErrorArray(array('section' => 'Could not extract embedded thumbnail contents from "' . $this->locationPath . '/' . $this->fileName . '"'));
     }
    }

}

}

?>

The class is being used to literally generate a thumbnail from an existing image. I read in the PHP manual (see http://us3.php.net/manual/en/function.exif-thumbnail.php ) that exif_thumbnail() only extracts embedded thumbnail information from a TIFF or JPEG
image. In knowing that I've simplified my method to only handle TIFF or JPEG images (this is done in the class constructor - sorting out what image type you got).

At this point, however, I am receiving nothing into the $thumbStreamObj binary stream string variable; it's "empty" (false):

$thumbstreamObj = exif_thumbnail($this->locationPath . '/' . $this->fileName, $width, $height, $mimeTypeInt);

I checked the values of $this->fileName and $this->locationPath and both contain the correct values to be able to locate the image in the system for the function to extract the embedded thumbnail information reportedly found in TIFF and JPEG images.

Has anyone had any luck using this to create a thumbnail? I could use some more experted advice than I would think to find in the manual notes, which I am certain I'll find among you gurus here.

Thanx
Phil

[jpmoriarty]

can i ask how you know that your jpegs have embedded thumbs? I don't think they do by default - they have to be put there when the jpeg's created

[ppowell]

Unfortunately you don't know. It turns out that some JPEG and TIFF images, like those taken with certain digital cameras, have EXIF embedded thumbnail information built in which can be extracted with exif_thumbnail(). What I wound up doing was to build a failsafe that would resize/clone the image into a thumbnail if that EXIF information could not be extracted from the original image.

Phil

[ju_ngelito]

Wrestling with thumbnails my self, but this simple bit of code should tell you whether or not an image contains a thumbnail....
If not, you can handle things in a different way (resize the image for example)

if(exif_thumbnail($image)===false)
{
echo("<B>No thumbnail in image!</B>");
}
else
{
$tmp = exif_thumbnail($image,$width,$heigth,$type);
etc. etc.
}

If the image contains a thumbnail, this works great. Things for me get difficult because the thumbnails in my (Kodak camera taken) pictures are in TIFF format, and will not show as an in-line image (using <IMG src= etc.)

Success!

[ppowell]

That would only work if all of your images were of JPEG or TIFF format that compat with exif_thumbnail() specifications. In my case that is not true, so I have to create different scenarios based upon image type.

Thanx though
Phil