[Resolved] GD not resizing all photos

[tomandhannah]

I have a script that will resize photos to create thumbnails using GD2. (JPG only, of course)... but it doesn't always work. Most JPGs do work, but some do not. And I have no idea why! It does copy the file and rename it, but it won't resize. I've attached a file it will not resize (u2.jpg). And the code is below. Why is this so inconsistent?

function thumbnail($realname,$maxwidth,$maxheight,$savepath,$originalpath) {

$fullpath = "/full/path/to/my/directory"; /***** With no trailing slash *****/
$thumb = $fullpath . $savepath . "t" . $realname;
$filename = $fullpath . $originalpath . $realname;
$thumbname = "t" . $realname;
@list($width, $height, $type, $attr) = getimagesize($thumb);

#Begin resizing

// Resize an image if it exceeds a predefined size.

  if (file_exists($filename) && (!file_exists($thumb)) && ($type = 2)) { /* check if the file is really one */
   $fd = @fopen($filename,"r");
   $image_string = fread($fd,filesize($filename));
   fclose($fd);

   $im = ImageCreateFromString($image_string);
   $currwidth = ImageSX($im);
   $currheight = ImageSY($im);

/* now we have to check if the image
    is higher than wider and larger
    than the defined size, then
    calculte it and resize it proportional */
   if ($currwidth > $currheight && $currwidth > $maxwidth) {
    $percent = ($maxwidth * 100) / $currwidth;
    $nwidth = $maxwidth;
    $nheight = ($percent * $currheight) / 100;
   } elseif ($currwidth < $currheight && $currheight > $maxheight) {
    $percent = ($maxheight * 100) / $currheight;
    $nheight = $maxheight;
    $nwidth = ($percent * $currwidth) / 100;
   } else {
    $nheight = $currheight;
    $nwidth = $currwidth;
    }
   $nwidth = intval($nwidth);
   $nheight = intval($nheight);

/* ok. let's create the new smaller image
    with calculated size... */
   $newim = imagecreatetruecolor ($nwidth - 1, $nheight - 1);

/* ...and put the larger image into the
    smaller one. */
imagecopyresized($newim,$im,0,0,0,0,$nwidth,$nheight,$currwidth,$currheight);

$newfilename = $fullpath . $savepath . "t" . $realname;

   /* now save to file and clear up the memory */
   imagejpeg($newim,$newfilename,90);
   ImageDestroy($im);
   ImageDestroy($newim);
   return $thumbname; 

  } elseif (file_exists($thumb)) {
  return $thumbname;

  } else {
   /* if the file wasn't a file return false */
   return false;

  }

#End resizing

}

[jpmoriarty]

i think the problem is your if testing.

currently it basically says:

if the pic is landscape and the width is too big, do this
otherwise, if the pic is portrait and the height is too big do this
otherwise it's okay.

but what about if it's landscape and the height is too big (for example you set maxheight x maxwidth to be 500 x 600. but a pic is 700 x 400. in this case, width is greater than height, but the height is less than your limit, so it won't do anything.)

how about we say that A is the max width and B the max height, and a is the width of your pic and b is the height. then you need to do something like this:

width_ratio = A/a
height_ratio = B/b

if a<=A and b<=B
dont do anything
elseif (width_ratiob) < B
image_height = ceil(width_ratio b)
image_width = A
otherwise
image_width = ceil(height_ratio * a)
image_height = B

hope that makes sense.

[tomandhannah]

Thanks John. Actually, you were wrong, but you got me to thinking and it helped me to find the problem! Actually, the 'if' statements allow for both portrait and landscape as you mention.

Then you said, "but what about if it's landscape and the height is too big" If it's landscape (width greater than height) and the height is too big, then the width will also be too big. In your example: maxheight= 500 & maxwidth = 600 with an image that is w700 x h400. The width is greater than the height: so it will resize b/c 700 > 600.

Anyway, the problem is that there is no case for a square image! All the images I uploaded that didn't resize had a height = width. So, I did this:

/* now we have to check if the image
    is higher than wider and larger
    than the defined size, then
    calculte it and resize it proportional */
   if ($currwidth > $currheight && $currwidth > $maxwidth) {
    $percent = ($maxwidth * 100) / $currwidth;
    $nwidth = $maxwidth;
    $nheight = ($percent * $currheight) / 100;
   } elseif ($currwidth < $currheight && $currheight > $maxheight) {
    $percent = ($maxheight * 100) / $currheight;
    $nheight = $maxheight;
    $nwidth = ($percent * $currwidth) / 100;
   } elseif ($currwidth = $currheight && 
      ($currheight > $maxheight || $currwidth > $maxwidth)) {
    $nheight = $maxheight;
    $nwidth = $maxheight;
   } else {
    $nheight = $currheight;
    $nwidth = $currwidth;
    }
   $nwidth = intval($nwidth);
   $nheight = intval($nheight);

This solves the problem of resizing, but the resized square images come out almost completely one color with lines streaking across them. I have no idea why. Portrait or landscape images still work fine, but my square images are messed up.

Anyone know why?

[tomandhannah]

In case any one is following this, I fixed the problem. The line that reads:

} elseif ($currwidth = $currheight &&

Should read:

} elseif ($currwidth == $currheight &&

At least, with my version of PHP (4.3) this solved the problem. Just needed double equal signs!