PHP GD Resize

php-image-resize.php

/**
* @param $file Path to source file
* @param $dest Path to save the image
* @param $type Method of resizing ('resize', 'resizemin', 'resizecrop', 'crop')
* @param $size Dimensions, array of width and height or maxScale
* @param $output Type of file to save it as ('jpg', 'png', 'gif')
* @param $quality 0 < x < 100
*/
function image ($file, $dest, $type, $size, $output = NULL, $quality = NULL, &$error = '') {
	
	if (is_null($type)) $type = 'resize';
	if (is_null($size)) $size = 100;
	if (is_null($output)) $output = 'jpg';
	if (is_null($quality)) $quality = 75;
	
	// -- format variables
	$type = strtolower($type);
	$output = strtolower($output);
	if (is_array($size)) {
		$maxW = intval($size[0]);
		$maxH = intval($size[1]);
	} else {
		$maxScale = intval($size);
	}
	
	// -- check sizes
	if (isset($maxScale)) {
		if (!$maxScale) {
			$error = "Max scale must be set";
			return false;
		}
		$maxW = $maxH = $maxScale;
	} else {
		if (!$maxW || !$maxH) {
			$error = "Size width and height must be set";
			return false;
		}
		if ($type == 'resize') {
			$error = "Provide only one number for size";
			return false;
		}
	}
	
	// -- check output
	if ($output != 'jpg' && $output != 'png' && $output != 'gif') {
		$error = "Cannot output file as " . strtoupper($output);
		return false;
	}
	
	if (is_numeric($quality)) {
		$quality = intval($quality);
		if ($quality > 100 || $quality < 1) {
			$quality = 75;
		}
	} else {
		$quality = 75;
	}
	
	// -- get some information about the file
	$uploadSize = getimagesize($file);
	$uploadWidth  = $uploadSize[0];
	$uploadHeight = $uploadSize[1];
	$uploadType = $uploadSize[2];
	
	if ($uploadType != 1 && $uploadType != 2 && $uploadType != 3) {
		$error = "File type must be GIF, PNG, or JPG to resize";
		return false;
	}
	
	switch ($uploadType) {
		case 1: $srcImg = imagecreatefromgif($file); break;
		case 2: $srcImg = imagecreatefromjpeg($file); break;
		case 3: $srcImg = imagecreatefrompng($file); break;
		default: $error = "File type must be GIF, PNG, or JPG to resize"; return false;
	}
				
	switch ($type) {
	
		case 'resize':
			# Maintains the aspect ration of the image and makes sure that it fits
			# within the maxW and maxH (thus some side will be smaller)
			// -- determine new size
			if ($uploadWidth > $maxScale || $uploadHeight > $maxScale) {
				if ($uploadWidth > $uploadHeight) {
					$newX = $maxScale;
					$newY = ($uploadHeight*$newX)/$uploadWidth;
				} else if ($uploadWidth < $uploadHeight) {
					$newY = $maxScale;
					$newX = ($newY*$uploadWidth)/$uploadHeight;
				} else if ($uploadWidth == $uploadHeight) {
					$newX = $newY = $maxScale;
				}
			} else {
				$newX = $uploadWidth;
				$newY = $uploadHeight;
			}
			
			$dstImg = imagecreatetruecolor($newX, $newY);
			imagecopyresampled($dstImg, $srcImg, 0, 0, 0, 0, $newX, $newY, $uploadWidth, $uploadHeight);
			
			break;
			
		case 'resizemin':
			# Maintains aspect ratio but resizes the image so that once
			# one side meets its maxW or maxH condition, it stays at that size
			# (thus one side will be larger)
			#get ratios
			$ratioX = $maxW / $uploadWidth;
			$ratioY = $maxH / $uploadHeight;

			#figure out new dimensions
			if (($uploadWidth == $maxW) && ($uploadHeight == $maxH)) {
				$newX = $uploadWidth;
				$newY = $uploadHeight;
			} else if (($ratioX * $uploadHeight) > $maxH) {
				$newX = $maxW;
				$newY = ceil($ratioX * $uploadHeight);
			} else {
				$newX = ceil($ratioY * $uploadWidth);		
				$newY = $maxH;
			}

			$dstImg = imagecreatetruecolor($newX,$newY);
			imagecopyresampled($dstImg, $srcImg, 0, 0, 0, 0, $newX, $newY, $uploadWidth, $uploadHeight);
		
			break;
			
		case 'resizemax':
			# Maintains aspect ratio but resizes the image so that once
			# one side meets its maxW or maxH condition, it stays at that size
			# (thus one side will be small)
			#get ratios
			$ratioX = $maxW / $uploadWidth;
			$ratioY = $maxH / $uploadHeight;

			#figure out new dimensions
			if (($uploadWidth == $maxW) && ($uploadHeight == $maxH)) {
				$newX = $uploadWidth;
				$newY = $uploadHeight;
			} else if (($ratioX * $uploadHeight) < $maxH) {
				$newX = $maxW;
				$newY = ceil($ratioX * $uploadHeight);
			} else {
				$newX = ceil($ratioY * $uploadWidth);		
				$newY = $maxH;
			}

			$dstImg = imagecreatetruecolor($newX,$newY);
			imagecopyresampled($dstImg, $srcImg, 0, 0, 0, 0, $newX, $newY, $uploadWidth, $uploadHeight);
		
			break;
		
		case 'resizecrop':
			// -- resize to max, then crop to center
			$ratioX = $maxW / $uploadWidth;
			$ratioY = $maxH / $uploadHeight;

			if ($ratioX < $ratioY) { 
				$newX = round(($uploadWidth - ($maxW / $ratioY))/2);
				$newY = 0;
				$uploadWidth = round($maxW / $ratioY);
				$uploadHeight = $uploadHeight;
			} else { 
				$newX = 0;
				$newY = 0; //round(($uploadHeight - ($maxH / $ratioX))/2);
				$uploadWidth = $uploadWidth;
				$uploadHeight = round($maxH / $ratioX);
			}
			
			$dstImg = imagecreatetruecolor($maxW, $maxH);
			imagecopyresampled($dstImg, $srcImg, 0, 0, $newX, $newY, $maxW, $maxH, $uploadWidth, $uploadHeight);
			
			break;
		
		case 'crop':
			// -- a straight centered crop
			$startY = ($uploadHeight - $maxH)/2;
			$startX = ($uploadWidth - $maxW)/2;

			$dstImg = imageCreateTrueColor($maxW, $maxH);
			ImageCopyResampled($dstImg, $srcImg, 0, 0, $startX, $startY, $maxW, $maxH, $maxW, $maxH);
		
			break;
		
		default: $error = "Resize function \"$type\" does not exist"; return false;
	}	

	// -- try to write
	switch ($output) {
		case 'jpg':
			$write = imagejpeg($dstImg, $dest, $quality);
			break;
		case 'png':
			$write = imagepng($dstImg, $dest . ".png", $quality);
			break;
		case 'gif':
			$write = imagegif($dstImg, $dest . ".gif", $quality);
			break;
	}
	
	// -- clean up
	imagedestroy($dstImg);
	
	if ($write) {
		return true;
	} else {
		$error = "Could not write " . $file . " to " . $dest;
		return false;
	}
}