CODEWITHSUNDEEP
phpgd
Andrew G. Johnson
Andrew G. Johnson

Reputation: 26993

Having issues with GD thumbnail generator

I'm using PHP to generate thumbnails. The problem is that I have a set width and height the thumbnails need to be and often times the images are stretched.

What I'd like is the image to remain at the same proportions and just have black filler (or any color) either on the left & right for tall images or top & bottom for wide images.

Here is the code I'm currently using: (dumbed down a bit for readability)

$temp_image_file = imagecreatefromjpeg("http://www.example.com/image.jpg");

list($width,$height) = getimagesize("http://www.example.com/image.jpg");

$image_file = imagecreatetruecolor(166,103);

imagecopyresampled($image_file,$temp_image_file,0,0,0,0,166,103,$width,$height);
imagejpeg($image_file,"thumbnails/thumbnail.jpg",50);

imagedestroy($temp_image_file);
imagedestroy($image_file);

Upvotes: 0

Views: 1286

Answers (5)

CodeChap
CodeChap

Reputation: 4262

This rescales the image to the larger size of the width and height and then crops it to the correct size.

// Crete an image forced to width and height
    function createFixedImage($img, $id=0, $preFix=false, $mw='100', $mh='100', $quality=90){

        // Fix path
        $filename = '../'.$img;

        // Check for file
        if(file_exists($filename))
        {           
            // Set a maximum height and width
            $width = $mw;
            $height = $mh;

            // Get new dimensions
            list($width_orig, $height_orig) = getimagesize($filename);

            $ratio_orig = $width_orig/$height_orig;

            if ($width/$height < $ratio_orig) {
                   $width = $height*$ratio_orig;
            }else{
                   $height = $width/$ratio_orig;
                }

            // Resample
            $image_p = imagecreatetruecolor($mw, $mh);
            $image = imagecreatefromjpeg($filename);
            imagecopyresampled($image_p, $image, 0, 0, 0, 0, $width, $height, $width_orig, $height_orig);

            // Output
            imagejpeg($image_p, "../images/stories/catalog/{$preFix}{$id}.jpg", $quality);
        }
    }

Upvotes: 0

Alnitak
Alnitak

Reputation: 339786

Here's a function I wrote that takes a GD image object, max width, max height, and rescales within those parameters:

function resized($im, $mx, $my) {
  $x = $nx = imagesx($im);
  $y = $ny = imagesy($im);
  $ar = $x / $y;
  while ($nx > $mx || $ny > $my) {
    if ($nx > $mx) {
      $nx = $mx;
      $ny = $nx / $ar;
    }
    if ($ny > $my) {
      $ny = $my;
      $nx = $ny * $ar;
    }
  }
  if ($nx != $x) {
    $im2 = imagecreatetruecolor($nx, $ny);
    imagecopyresampled($im2, $im, 0, 0, 0, 0, $nx, $ny, $x, $y);
    return $im2;
  } else {
    return $im;
  }
}

If the resulting image doesn't need rescaling then it just returns the original image.

Upvotes: 1

Andrew G. Johnson
Andrew G. Johnson

Reputation: 26993

Okay got it working, here's what I ended up doing:

$filename = "http://www.example.com/image.jpg";

list($width,$height) = getimagesize($filename);

$width_ratio = 166 / $width;
if ($height * $width_ratio <= 103)
{
    $adjusted_width = 166;
    $adjusted_height = $height * $width_ratio;
}
else
{
    $height_ratio = 103 / $height;
    $adjusted_width = $width * $height_ratio;
    $adjusted_height = 103;
}

$image_p = imagecreatetruecolor(166,103);
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p,$image,ceil((166 - $adjusted_width) / 2),ceil((103 - $adjusted_height) / 2),0,0,ceil($adjusted_width),ceil($adjusted_height),$width,$height);

imagejpeg($image_p,"thumbnails/thumbnail.jpg",50);

Upvotes: 1

Kevin Tighe
Kevin Tighe

Reputation: 21161

You'll need to calculate the new width & height to keep the image proportionat. Check out example 2 on this page:

https://www.php.net/imagecopyresampled

Upvotes: 2

da5id
da5id

Reputation: 9136

Have a look at this upload class. It does what you want and a lot more besides.

Upvotes: 0

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