Imagick Resize, Center, and Sparse Fill problems

Question

My end goal here is to resize the input image to 100px width, 125px height. Some of the input images are a different Aspect Ratio, so I wish for them to be in a 100x125 container with the background sparse filled from their edge color.

Ok, so this works for the basic resize:

$image = new Imagick($imgFile);
$image->resizeImage(100,0, Imagick::FILTER_LANCZOS, 1, false);
$image->writeImage("$Dir/$game.png");
header("Content-type: ".$image->getImageFormat());
echo $image;
$image->clear();
$image->destroy();

However I've been searching for hours, and I cannot find a simple "This is how you center an image in a canvas" bit for PHP's Imagick library. Everything is for the actual ImageMagick convert application, which is not really what I'm after. I've tried compositing the resized image into an empty newImage with the set width and height, but it just seems to overwrite the dimensions regardless of the composite type, setting the Gravity to center and then the extent to 100x125 has no effect ( It always sits at 0,0, and trying to set the y offset to ((125-imageheight)/2) resulted in an offset that was way more than it should have been )

Edit:

    $imageOutput = new Imagick();
    $image = new Imagick($imgFile);
    $image->resizeImage(100,0, Imagick::FILTER_LANCZOS, 1, false);
    $imageOutput->newImage(100, 125, new ImagickPixel('black'));
    $imageOutput->compositeImage($image, Imagick::COMPOSITE_ADD, 0, ((125 - $image->getImageHeight()))/2 );
    $imageOutput->setImageFormat('png');
    $imageOutput->writeImage("$Dir/$game.png");
    header("Content-type: ".$imageOutput->getImageFormat());
    echo $imageOutput;
    $image->clear();
    $image->destroy();

So I got my centering working, gravity apparently has no effect on actual images.

I have absolutely no idea where I would even begin to try and recreate a command line edge-in sparse fill in PHP with the library.

Answer 1

I ended up using a combination of Imagick and shell calls to convert itself, I'll eventually rewrite it to use entirely shell calls. I also changed my dimensions, here's the code:

    $imageOutput = new Imagick(); // This will hold the resized image
    $image = new Imagick($imgFile); // Open image file
    $image->resizeImage(120,0, Imagick::FILTER_LANCZOS, 1, false); // Resize it width-wise
    $imageOutput->newImage(120, 150, "none"); // Make the container with transparency
    $imageOutput->compositeImage($image, Imagick::COMPOSITE_ADD, 0, ((150 - $image->getImageHeight())/2) ); // Center the resized image inside of the container
    $imageOutput->setImageFormat('png'); // Set the format to maintain transparency
    $imageOutput->writeImage("$Dir/$game.temp.png"); // Write it to disk
    $image->clear(); //cleanup -v
    $image->destroy(); 
    $imageOutput->clear();
    $imageOutput->destroy();
    //Now the real fun
    $edge = shell_exec("convert $Dir/$game.temp.png -channel A -morphology EdgeIn Diamond $Dir/$game.temp.edge.png"); // Get the edges of the box, create an image from just that
    $shepards = shell_exec("convert $Dir/$game.temp.edge.png txt:- | sed '1d; / 0) /d; s/:.* /,/;'"); // get the pixel coordinates
    $final = shell_exec("convert $Dir/$game.temp.edge.png -alpha off -sparse-color shepards '$shepards' png:- | convert png:- $Dir/$game.temp.png -quality 90 -composite $Dir/$game.jpg"); // Sparse fill the entire container using the edge of the other image as shepards , then composite that on top of this new image
    unlink("$Dir/$game.temp.png"); // cleanup temp files
    unlink("$Dir/$game.temp.edge.png");
    set_header_and_serve("$Dir/$game.jpg"); // serve the newly created file