Images: Resizing-Keeping ratios

[mysql_query]

Hello. I want to resize an image to something around 90 by 90. The problem is, if all images are resized to 90 by 90, they will look like crud. Therefore, I need a way to keep the ratios between lengths and heights. For example: 500 by 600 turns to 50 by 60. Can PHP do something like this? If not, than what can? Take a look a how deviantart.com resizes the pictures. They all look good. Is there a way?

Thanks.

[jpmoriarty]

<?
      if (@!$max_width)
        $max_width = 100;
      if (@!$max_height)
        $max_height = 700;

  $directory = "photos";
  $file = $directory."/".$file;

  $size = GetImageSize($file);
  $width = $size[0];
  $height = $size[1];

  $x_ratio = $max_width / $width;
  $y_ratio = $max_height / $height;

  if ( ($width <= $max_width) && ($height <= $max_height) ) {
    $tn_width = $width;
    $tn_height = $height;
  }
  else if (($x_ratio * $height) < $max_height) {
    $tn_height = ceil($x_ratio * $height);
    $tn_width = $max_width;
  }
  else {
    $tn_width = ceil($y_ratio * $width);
    $tn_height = $max_height;
  }

  $src = ImageCreateFromJpeg($file);
  $dst = ImageCreateTrueColor($tn_width,$tn_height);
  ImageCopyResized($dst, $src, 0, 0, 0, 0,
      $tn_width,$tn_height,$width,$height);
  header("Content-type: image/jpeg");
  ImageJpeg ($dst, '', 75);
  ImageDestroy($src);
  ImageDestroy($dst);

?>

[mysql_query]

Whoa...

Thanks John. Wasn't expecting a ready code. Thanks a lot.

Cheers!

[jpmoriarty]

must admit never really taken the time to go through it and work out what every step does, but you can quite easily spot (and it's not too difficult to see the theory behind) the ratio keeping features.

Hope it helps / helped

[mysql_query]

Hello. I'm having a bit of trouble with the above script. After I figured out how to install GD on my Windows test machine and got everything working, the output (ImageJpeg()) comes out with very wierd characters. I have checked that the system finds the file (if ($file) { echo "pic found";}), and I got that it does in fact find the picture. The picture is in a JPEG compression (when it was gif compression with .jpg extension, it was giving me countless errors). I don't know what's wrong, since these functions are foreign to me. I have looked them all up, but still can't find the problem. Please help. Here is a copy of the code (slightly changed):

ob_start();    

 if (@!$max_width)
        $max_width = 100;
      if (@!$max_height)
        $max_height = 700;

  $directory = "pics";
  $file = $directory."/apache.jpg";//my picture

  $size = GetImageSize($file);
  $width = $size[0];
  $height = $size[1];

  $x_ratio = $max_width / $width;
  $y_ratio = $max_height / $height;

  if ( ($width <= $max_width) && ($height <= $max_height) ) {
    $tn_width = $width;
    $tn_height = $height;
  }
  else if (($x_ratio * $height) < $max_height) {
    $tn_height = ceil($x_ratio * $height);
    $tn_width = $max_width;
  }
  else {
    $tn_width = ceil($y_ratio * $width);
    $tn_height = $max_height;
  }

  $src = ImageCreateFromJpeg($file);
  $dst = ImageCreateTrueColor($tn_width,$tn_height);
  ImageCopyResized($dst, $src, 0, 0, 0, 0,
      $tn_width,$tn_height,$width,$height);
  header("Content-type: image/jpeg");
  ImageJpeg ($dst, '', 75);//this seems to malfunction
  ImageDestroy($src);
  ImageDestroy($dst);
ob_end_flush();
?>

Thanks.

[mysql_query]

Please help...

Just keeping this topic from dying before i get an answer

Thanks.

[jpmoriarty]

this script generates a jpg image.

That might sound like an obvious statement, but think about it for a while. It generates the "stuff" that goes into a jpg file.

This means that if you took the output from this script, saved it as a file.jpg, and openend it in paint shop pro, it would be a jpg image.

Now, consider how images are put into HTML pages. Do you have to open an image in notepad and look at all the funny letters and characters, copy them and then paste them into HTML? No. You do not.

What you do is link to the jpg image using the <img> codes. And that's exactly what you do here.

Except you dont link to a jpg, you link to the php file which generates the jpg.

So all you need to do is have a line in your php code which is akin to:

echo "<img src=\"makeimage.php?max_width=50&max_height=50\">";

This is why I gave you the code with $file in it, and you should leave it like that. By changing the $file to apache.jpg you make it so that the file can create only one jpg - if that's the case, then you might as well just resize the image yourself and put it in there. the line should read:

echo "<img src=\"makeimage.php?max_width=50&max_height=50&file=apache.jpg\">";

and you should change that line back to $file. Also note that this was written when i used global variables. You really should change all those to $_GET[''] variables, but worry about that later if i were you.

Also, you cant have a gif and just give it a jpg extension and expect this file (or any image browser) to know what to do. They use completely different compression methods which are totally incompatible: it's like saying "my brother is fluent in french and german, so I gave him some spanish (on the front of which i'd written "this is french") and asked him to translate it into german, but he couldnt. Why not?" Also gif's arent supported by the gd due to licensing and copyright.

[mysql_query]

Ok, I got it...thanks a lot.

I didn't realize I had to call it like a regular image. I already knew about compressions (jpeg vs. gif, etc.). Thanks a lot John.

Cheers!