Preserve image's aspect ratio when width AND height defined

Please ignore the previous patch, it doesn't work. Here's the function I've changed. The problem is that the call to getimagesize is returning false, though the url seems to be right, eg
"http://farm4.static.flickr.com/3297/3236587333_3f71cdf1e9_o.jpg"

Any ideas why getimagesize doesn't work, or ideas of other ways to find the image's dimensions?

function theme_emimage_image($field, $item, $formatter, $node, $code, $width, $height, $title = '', $link = NULL) {
  $url = module_invoke('emfield', 'include_invoke', 'emimage', $item['provider'], 'image_url', $code, $width, $height, $formatter, $field, $item, $node);
  $attributes = array();
  
  // Set the image's width or height attribute for the browser, and let the browser scale 
  // the image, preserving its original aspect ratio.
  // There are three options allowed in the admin settings:
  // 1. width == 0. Display image at specified height, 
  //    with width scaled according to original aspect ratio.
  // 2. height == 0. Display image at specified width, 
  //    with height scaled according to original aspect ratio.
  // 3. Both width and height are non-zero. Change it to display the image 
  //    at the largest size that fits within the specified height & width, 
  //    and preserves the original aspect ratio.

  if ($width == 0) {
    $attributes['height'] = $height;
  } 
  elseif ($height == 0) {
    $attributes['width'] = $width;
  }
  else {
    // Find out the size of the actual image file, and scale accordingly
	list($actual_width, $actual_height, $type, $image_attributes) = getimagesize($url) ;
	if ( ($actual_width >0 ) && ($actual_height >0) ) {
	  $scale_width = $actual_width / $width ;
	  $scale_height = $actual_height / $height ;
	  if ($scale_width < $scale_height) {
	    $attributes['width'] = $width;
	  } 
	  else {
	    $attributes['height'] = $height;
	  }
	}
	else {
	  // getimagesize didn't work, so set both. Safer, but will lose aspect ratio.
	  $attributes['width'] = $width;
	  $attributes['height'] = $height;	  
	}
  }

  if ($item['class']){
      $attributes['class'] = $item['class'];
  }
  else if ($item['provider']) {
      $attributes['class'] = $item['provider'];
  }
  $output = theme('image', $url, $title, $title, $attributes, false);
  
  if ($link) {
    $output = l($output, $link, array('html' => true));
  }
  return $output;
}

The following code works (it uses curl instead of getimagesize), but fetching the image every time it is displayed is a bit crazy. Any suggestions on the right way to approach this?

I'm thinking to have theme_emimage_image just look in $item for width and height entries, and have emfield_PROVIDER_data responsible for setting those values when the node is initially created. It looks like picasa.inc already does this. Does that sound right?

function theme_emimage_image($field, $item, $formatter, $node, $code, $width, $height, $title = '', $link = NULL) {
  $url = module_invoke('emfield', 'include_invoke', 'emimage', $item['provider'], 'image_url', $code, $width, $height, $formatter, $field, $item, $node);
  $attributes = array();
  
  // Set the image's width or height attribute for the browser, and let the browser scale 
  // the image, preserving its original aspect ratio.
  // There are three options allowed in the admin settings:
  // 1. width == 0. Display image at specified height, 
  //    with width scaled according to original aspect ratio.
  // 2. height == 0. Display image at specified width, 
  //    with height scaled according to original aspect ratio.
  // 3. Both width and height are non-zero. Change it to display the image 
  //    at the largest size that fits within the specified height & width, 
  //    and preserves the original aspect ratio.

  if ($width == 0) {
    $attributes['height'] = $height;
  } 
  elseif ($height == 0) {
    $attributes['width'] = $width;
  }
  else {
    // Find out the size of the actual image file, and scale accordingly
	$actual_width = false ;
	$actual_height = false ;

	
// THE 'getimagesize' CODE HAS NOT BEEN TESTED YET, 
// THOUGH THE CURL CODE BELOW IS WORKING OK	

	if (ini_get('allow_url_fopen')) {
	  // It is safe to call getimagesize on a remote file
	  $size = @getimagesize($url) ;
	  if ($size !== false) {
	    $actual_width = $size[0] ;
		$actual_height = $size[1] ;
	  }
	}
	elseif (function_exists('curl_exec')) {
	  // Many sites don't have 'allow_url_fopen' enabled, but if curl is
	  // enabled we can use that instead
	  $ch = curl_init();    // initialize curl handle
      curl_setopt($ch, CURLOPT_URL, $url); // set url to post to
      curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);// allow redirects
      curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); // return into a variable
      curl_setopt($ch, CURLOPT_TIMEOUT, 3); // times out after 4s
      $curl_file = curl_exec($ch); // run the whole process
      curl_close($ch);  
      $curl_image = @imagecreatefromstring($curl_file);
	  if ($curl_image !== false) {
	    $actual_width = @imagesx($curl_image); 
		$actual_height = @imagesy($curl_image); 
	  }
	  unset($curl_file, $curl_image);
	}
	
	if ( $actual_width && $actual_height ) {
	  $scale_width = $actual_width / $width ;
	  $scale_height = $actual_height / $height ;
	  if ($scale_width > $scale_height) {
	    $attributes['width'] = $width;
	  } 
	  else {
	    $attributes['height'] = $height;
	  }
	}
	else {
	  // We don't know the size of the image, so just make it fill the space available.
	  // It will probably be stretched in one direction, making it look odd.
	  $attributes['width'] = $width;
	  $attributes['height'] = $height;	  
	}
  }

  if ($item['class']){
      $attributes['class'] = $item['class'];
  }
  else if ($item['provider']) {
      $attributes['class'] = $item['provider'];
  }
  $output = theme('image', $url, $title, $title, $attributes, false);
  
  if ($link) {
    $output = l($output, $link, array('html' => true));
  }
  return $output;
}

This works for me - please can you let me know if it's ok for you too.

The first patch is to theme_emimage_image in emimage.theme.inc. This version looks to see if emfield_PROVIDER_data had set values for the image's height & width, and if yes it scales the image to fit within the specified size, while preserving its aspect ratio. If they are not set, it behaves like the current beta1 version.

The second patch is to flickr.inc, so that it sets the height & width required above.

If you have an existing embedded flickr image, you'll need to edit & save it (no need to make any changes) before you see the effects of these patches.

Hi, moving this back to active, as the problem & patch I'm describing are different from that in #8. I'll try and explain it better.

I want to use Views to build a gallery of emfield images, and have it display as a grid of images, just like any other gallery you see on the web.

I set the dimensions of the thumbnail to be 150x150. See 150x150-org.jpg. That shows a grid, but all images are stretched to fit the 150x150 square shape, so they are distorted.

I read that setting one dimension to 0 preserves the aspect ratio, so I tried dimensions of 150x0. See 150x0-org.jpg. Now the images looks ok, but the gallery looks wrong. Portrait images always appear much larger than landscape images, not how a gallery usually looks.

So, the patch in #5 preserves the aspect ratio, AND fits the image within the specified dimensions. After installing the patch, and setting the dimensions to 150x150 we get 150x150-patch.jpg, which I think looks better.