Crop image from center and output a square cropped image; written in PHP language.

autocrop_center_square.php

<?php
function cropAlign($image, $cropWidth, $cropHeight, $horizontalAlign = 'center', $verticalAlign = 'middle') {
    $width = imagesx($image);
    $height = imagesy($image);
    $horizontalAlignPixels = calculatePixelsForAlign($width, $cropWidth, $horizontalAlign);
    $verticalAlignPixels = calculatePixelsForAlign($height, $cropHeight, $verticalAlign);
    return imageCrop($image, [
        'x' => $horizontalAlignPixels[0],
        'y' => $verticalAlignPixels[0],
        'width' => $horizontalAlignPixels[1],
        'height' => $verticalAlignPixels[1]
    ]);
}

function calculatePixelsForAlign($imageSize, $cropSize, $align) {
    switch ($align) {
        case 'left':
        case 'top':
            return [0, min($cropSize, $imageSize)];
        case 'right':
        case 'bottom':
            return [max(0, $imageSize - $cropSize), min($cropSize, $imageSize)];
        case 'center':
        case 'middle':
            return [
                max(0, floor(($imageSize / 2) - ($cropSize / 2))),
                min($cropSize, $imageSize),
            ];
        default: return [0, $imageSize];
    }
}


// Put your image here
$fname = "a.jpg";

// Get dimensions of the coriginal image
$imgsz = getimagesize($fname);
$minsz = min($imgsz[0], $imgsz[1]);

// Determine image mime type
if(exif_imagetype($fname) != IMAGETYPE_JPEG){
	// For PNG
	$im = imagecreatefrompng($fname);
	$kal = cropAlign($im, $minsz, $minsz, 'center', 'middle');
	imagePng($kal, "cropped_" . $fname);
}else{
	// For JPEG
	$im = imagecreatefromjpeg($fname);
	$kal = cropAlign($im, $minsz, $minsz, 'center', 'middle');
	imageJpeg($kal, "cropped_" . $fname);
}

?>