GD image batch processing from directory

Question

Really racking my brain, I've been looking into this for 2+ days.

Goal? Click/select a subdirectory with images; on Submit, a batch process will run using GD on the whole DIR chosen, creating thumbs in a /thumbs folder on the same server.

Status? I can do this for a single file at a time, need to do multiple files at once.

Here's my functioning one-off code:

$filename = "images/r13.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,"images/thumbs/r13.jpg",70);

As you can see, the script is targetting a single file, I would like to iterate through a directory instead of specifying a name.

(I will also look into imagemagick, but at the moment it is not an option.)

I'll keep going through SO etc, but any help would be tremendous.

Thanks.

score 4 · Accepted Answer · answered Nov 01 '12 at 17:03

you need to make a function from this code:

function processImage($filename){
    list($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($image_p,"images/thumbs/".basename($filename),70);
    imagedestroy($image_p);
}

Please note last two lines of this function: it writes thumb basing on passed fiulename and destroys resource, to free memory.

Now apply this to all files in directory:

foreach(glob('images/*.jpg') AS $filename){
    processImage($filename);
}

and basically that's it.

dev-null-dweller, that worked perfectly. Thank you (and R.S) for replying so fast. I am new to answering on SO - how do I mark this question as answered? — JWC_WDC, Nov 01 '12 at 17:15
on the left side of an answer there should be ✅, just click it and it will turn green — dev-null-dweller, Nov 01 '12 at 17:17
@dev-null-dweller I tried your solution and change some values to 150px square then when i run it, it works but when I checked the thumbnails, it has this black lines on top and bottom. the original sizes was larger than 150 which should be enough to crop the image to 150px. — anagnam, Jul 31 '13 at 06:15

GD image batch processing from directory

1 Answers1